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Siemens RMB795B Basic Documentation

Central control unit for room controllers rxb/rxl and room thermostats rdg/rdf/rdu
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Synco
700
Central control unit RMB795B
For room controllers RXB/RXL and room thermostats RDG/RDF/RDU
Basic documentation
CE1P3122en
CE1P3122en
18.01.2012
18.01.2012
Infrastructure & Cities
Building Technologies
Building Technologies

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  • Page 1 Infrastructure & Cities Synco  Central control unit RMB795B For room controllers RXB/RXL and room thermostats RDG/RDF/RDU Basic documentation CE1P3122en CE1P3122en Building Technologies Building Technologies 18.01.2012 18.01.2012...
  • Page 2 Siemens Switzerland Ltd Sector Infrastructure & Cities Building Technologies Division Gubelstrasse 22 6301 Zug Schweiz Phone +41 41-724 24 24 © 2004-2012 Siemens Switzerland Ltd www.siemens.com/sbt Subject to change 2 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies...

  • Page 3: Table Of Contents

    Contents Overview ....................10 Central control unit RMB795B ..............10 Product range..................10 Synco™ 700 topology................12 Equipment combinations.................12 Product documentation ................13 Output .....................13 Important notes ..................14 Operation ....................16 Operation without operator unit...............16 Operation with operator unit..............17 2.2.1 Operator unit functions................17 2.2.2 Operating concept...................17 2.2.3...
  • Page 4 Release room unit QAX3x.x for time switch operating mode Economy .62 8.3.5 7-day time switch ..................63 8.3.6 Holidays/special days................64 8.3.7 Room operating mode outputs..............67 8.3.8 Functional check / wiring test ..............69 4 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Contents 18.01.2012...
  • Page 5 10.2 Fault priorities and acknowledgement ............90 10.3 Universal fault inputs................90 10.4 External fault button ................92 10.5 Fault relay ....................92 10.6 Functional check / wiring test..............94 Distribution zones.................95 5 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Contents 18.01.2012...
  • Page 6 Trend .....................121 15.1.1 Connections and application ..............121 15.1.2 Views.....................121 15.1.3 Trend function settings ................122 15.1.4 Troubleshooting..................123 15.2 Meters ....................123 15.2.1 Activate meters ..................124 15.2.2 Display format ..................124 6 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Contents 18.01.2012...
  • Page 7 Delete fault status messages..............132 17.3 Troubleshooting ..................133 Electrical connections................134 18.1 Connection rules ...................134 18.2 Connection terminals ................135 18.2.1 Central control unit RMB795B ..............135 18.2.2 Universal modules RMZ785..............135 18.2.3 Universal module RMZ787 ..............135 Appendix....................136 19.1 Abbreviations used ................136 19.2 Configuration diagram................136 19.2.1...
  • Page 8 8 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Contents 18.01.2012...
  • Page 9 9 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Overview 18.01.2012...

  • Page 10: Overview

    Overview Central control unit RMB795B What is the RMB795B The RMB795B is a central control and operator unit for room control in connection central control unit? with Synco RXB/RXL and with room thermostats RDG/RDF/RDU. It significantly extends the field of use of the Synco system.
  • Page 11 Operator units Operator unit, RMZ790 N3111 plug-in type Operator unit, RMZ791 N3112 detached Type of room unit QAW740 N1633 Operator unit 1 Service tool OCI700.1 N5655 11 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Overview 18.01.2012...

  • Page 12: Synco™ 700 Topology

    QAF81..., QAF64..., N1284, N1283, QFA81, QFM81, N1513, N1514, QFA1000, QFA1001, N1518, QFX21, QXA2000, N1541, N1542 QBM81... N1552 Volume flow G…B181.1E/3 N3544 controller VAV G…B181.1E/KN networked versions N3547 12 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Overview 18.01.2012...

  • Page 13: Product Documentation

    Environmental declaration (RMZ791) CE1E3110en04 Environmental declaration (RMZ792) CE1E3131en Output Overview Summary of the functions and features for the central control unit RMB795B: Outfit / functions RMB795B Canned applications Extension modules Extension with 2 universal modules RMZ787 each with 4 universal inputs and 4 relay outputs...

  • Page 14: Important Notes

    Only qualified staff trained by Siemens Building Technologies may preparte for use and commission Synco™ 700 products. Operation Synco™ 700 products may only be operated by staff instructed by Siemens Building Technologies or its delegates and who understand the potential risks. 14 / 144...
  • Page 15 For storage and transport, observe the limits from the relevant data sheets at all Storage and transport times. If in doubt, contact your supplier or Siemens Building Technologies. Maintenance Synco™ 700 products are maintenance-free and require only cleaning at regular intervals.

  • Page 16: Operation

    Operation Synco™ 700 devices may only be operated by staffs who has been instructed by Siemens Building Technologies or their delegates and whose attention has been drawn to potential risks. Operation without operator unit Operating elements Without the operator unit, the following operating elements on the central control...

  • Page 17: Operation With Operator Unit

    Brief description The operator unit is used to make all settings and readouts required for operating the RMB795B central control unit. All entries made on the operator unit are transmitted to the central control unit where they are handled and stored. The operator unit itself does not store any data.
  • Page 18 They can be replaced by the service engineer during commissioning by using project-related clear-text names. If, later, with the respective menu lines, the INFO button is pressed, the original default text will reappear. 18 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Operation 18.01.2012...

  • Page 19: Operating Levels

    2. Press the INFO button to change to the info level. 2.2.4 Access levels The RMB795B central control unit has 3 access levels. An access right is defined 3 access levels for each parameter (operating line). Level...
  • Page 20 The Access levels menu is displayed. 2. Select the required access level by turning the OK knob and confirm by pressing the knob. 3. Enter number 7 to access the password level. 20 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Operation 18.01.2012...

  • Page 21: Room Group Philosophy

    (e.g. radiators, chilled ceiling, fan coils, or VAV). The individual room controllers are assigned by entering the geographical zone address via the KNX bus of a room group of the RMB795B central control unit. Application example To explain the philosophy of the room group, we use the following example.
  • Page 22 • All other offices (room group 2). The fan coil units equipped with RXB room controllers were entered in the floor plan, and the addresses assigned accordingly: 22 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Room group philosophy 18.01.2012...
  • Page 23 • To each room group of the RMB795B control station. Here, all devices to be part of the same room group must have the same apartment number. On the RMB795B central control unit, only the room group, that is, the Settings on the control unit "Geographical zone (apartment)"...

  • Page 24: Implement Application Example

    2. Copy the device addresses for the bus members along with the basic settings for communication from the building floor plan. 3. Enter the geographical zone addresses as per the defined groups. 24 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Room group philosophy 18.01.2012...
  • Page 25 Upon commissioning, enter the settings for the same-name data points in the commissioning devices according to the created list. Other details For detailed descriptions of the choices and settings offered by the RMB795B central control unit, refer to the following chapters and sections of this document. 25 / 144 Siemens...

  • Page 26: Engineering And Commissioning Guidelines

    Based on the HVAC plant concept, the RXB/RXL room controllers and Synco room thermostats RDG/RDF/RDU must be assigned to room groups. Within these room groups, the RMB795B central control unit permits central control of time, calendar and special day programs, preselected setpoints, trend functions,...
  • Page 27 Planning 1: Steps required to implement the HVAC plant concept for the RMB795B central Implement HVAC plant control unit: concept step Procedure Notes Decide on the device types, their Number of RXB/RXL..., number and application RMB795B, QAW740, RMU7x, RDG/RDF/RDU, etc.
  • Page 28 • Setting a commissioning date on which the installation will be completed and all forms of energy (electricity, heat and refrigeration) will have to be available 28 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Engineering and commissioning guidelines...
  • Page 29 1. Set configuration and setting values according to the configuration diagram. 2. Make the wiring test. 3. Set the RMB795B communication data points according to the Synco Planning and Commissioning Protocol C3127. 4. Run search of device supervision 5.

  • Page 30: Commissioning

    Safety notes Preparation for use and commissioning of Synco™ 700 products must be undertaken by qualified staff trained by Siemens Building Technologies. • When the central control unit is in commissioning mode, control will remain off, that is, all outputs are set to a defined OFF state.

  • Page 31: Start Commissioning

    Main menu > Commissioning > Basic offered. configuration > Plant type Further procedure When commissioning the RMB795B central control unit for the first time, follow the Installation Instructions 74 319 0398 0 (G3140). They are enclosed with the RMB795B. 31 / 144...

  • Page 32: Start From The Main Menu

    • Assign the central control unit position to the connected extension modules 5.3.1 Select basic type "B" Selection deletes extra On the RMB795B central control unit, an empty "Basic configuration" is filed. If configuration selected, all configurations of the extra configuration will be deleted (for connections, refer to the configuration diagram).

  • Page 33: Assign Extension Modules

    5.3.2 Assign extension modules Selection The number of inputs and outputs of the RMB795B central control unit can be increased by attaching extension modules. Each central control unit RMB795B can be connected to these modules: Number Type Purpose RMZ785 Extension of inputs with 8 universal inputs.

  • Page 34: Create Free Configuration

    Create free configuration Application examples The central control unit RMB795B can be adapted to the needs of the plant with the help of configuration diagrams, see Sec. 19.2 Configuration diagram. Wiring test Functions A wiring test can be made after all peripheral devices are connected. We recommend testing after configuration and settings are complete.

  • Page 35: Exit Commissioning

    The entire commissioning data set (configuration and all settings) can be saved to Purpose the central control unit RMB795B after commissioning. If, in operation, an unauthorized user makes important readjustments, the function can be used to retrieve the state the device had after commissioning.

  • Page 36: Exit Password Level

    View device information Purpose Important information about the RMB795B central control unit, the connected extension modules, the configuration and the communication settings can be viewed on the Device information menu. Main menu > Device information > Controller...
  • Page 37 "Basic configuration" menu, the old or a new standard application (i.e. basic type B) is loaded. A new configuration will be made based on basic type "B". 37 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Commissioning 18.01.2012...

  • Page 38: General Settings

    (standard time) to 03:00 (daylight saving time), and from 03:00 (daylight saving time) to 02:00 (standard time). If both dates are set to coincide, daylight saving/standard time changeover is inactive. 38 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies General settings 18.01.2012...

  • Page 39: Communication

    Clock time operation Depending on the master clock , different sources for the time of day can be used. This can be selected on the RMB795B central control unit. Time of day and date can be exchanged via bus. The following setting available for clock time operation: •...

  • Page 40: Troubleshooting

    (1 master, all others as slaves). 6.1.3 Troubleshooting In connection with the time of day and date, the RMB795B central control unit Possible cases generates a fault status message in the following cases: • If the clock on the bus is missing and the local clock is parameterized as the clock time slave, operation continues with the internal clock and fault status message "System time failure"...

  • Page 41: Select Temperature Unit

    Select temperature unit Setting values On the RMB795B, the unit of temperature can be switched between °C /K and °F. Main menu > Commissioning > Settings > ..or Main menu > Settings > Device > Operating line Range Factory setting...

  • Page 42: Editable Text

    No, Yes Note The texts for the operating lines "Device name", "File", and "Business card line 1...4" are not deleted when the menu texts are reset. 42 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies General settings 18.01.2012...

  • Page 43: Inputs

    • Universal 0000: Universal input without decimal place, resolution –999…+9999, increment 1. • Digital • Pulse The identifier can provide additional functionality; see Sec. 7.5.2 "Outside temperature at terminal". 43 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Inputs 18.01.2012...

  • Page 44: Cause

    N.X1… ---- A8 (2).X4 Only authorized staff may override inputs within a limited period of time! The fault message "Simulation inputs active" is sent during terminal simulation. 44 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Inputs 18.01.2012...

  • Page 45: Troubleshooting

    The analog inputs can be activated as described in Sec. 7.1.2 "Activate function". With the analog inputs, the following settings can be made: • Type • Measuring range • Measured value correction 45 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Inputs 18.01.2012...

  • Page 46: Measuring Range

    With passive temperature sensors, the measured value can be readjusted by –3,0 to +3,0 K to compensate for line resistance. This can be used to perform on site calibration with a reference measuring unit. 46 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Inputs 18.01.2012...

  • Page 47: Connection Examples For Sensors

    Setting Type Ni1000 2 passive LG-Ni1000 temperature sensors can be connected to the input. The 2 sensors LG-Ni 1000 RMB795B central control unit calculates the average temperature. They must be connected according to the following diagram: B... B... LG-Ni 1000 LG-Ni 1000 X...

  • Page 48: Troubleshooting

    Display with the measured value: • Open-circuit: ---- • Short-circuit = oooo Text Effect Fault status messages 101… [N.X1] sensor error, Non urgent message; must not be [RMZ787(2).X4] acknowledged. sensor error 48 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Inputs 18.01.2012...

  • Page 49: Multiple Use Of Sensors

    Main menu > Settings > Inputs > ...X... Operating line Range Factory setting Text for: Logic 0 Max. 20 characters. Text for: Logic 1 Max. 20 characters. 49 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Inputs 18.01.2012...

  • Page 50: Connection Example

    • Choose wiring such that "Fire alarm off"is also triggered if there is no signal (open-circuit) • Setting for normal position: Closed. 50 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Inputs 18.01.2012...

  • Page 51: Pulse

    Main menu > Commissioning > Settings > ..or Main menu > Settings > Inputs > ...X... Operating line Range Factory setting Type Mechanically or electronically Mechanically 7.4.2 Connection diagram X... Reed pulse source. 51 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Inputs 18.01.2012...

  • Page 52: Outside Temperature

    Ni1000, 2xNi1000, T1, Pt1000, DC Ni1000 0…10 V Value low Depending on selected type. Depending on type. Value high Depending on selected type. Depending on type. Correction − 3.0…+3.0 K 52 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Inputs 18.01.2012...

  • Page 53: Outside Temperature Via Bus

    If, at this point in time, a measured measured value value is available and then missing later, a fault status message will be delivered: "[...X...]: Sensor error". 53 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Inputs 18.01.2012...

  • Page 54: Texts

    Urgent message; must be acknowledged. temperature sensor Outside temperature If the RMB795B central control unit expects an outside temperature from the bus via bus available? and that outside temperature is not communicated, the following fault status message will be delivered: "Outside temp sensor error".
  • Page 55 Max. 20 characters. RMZ787(1).X4 RMZ787(1).X4 Max. 20 characters. RMZ787(2).X1 RMZ787(2).X1 Max. 20 characters. RMZ787(2).X2 RMZ787(2).X2 Max. 20 characters. RMZ787(2).X3 RMZ787(2).X3 Max. 20 characters. RMZ787(2).X4 RMZ787(2).X4 Max. 20 characters. 55 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Inputs 18.01.2012...

  • Page 56: Function Block: "Room Group

    The most important features and functions of the room group are the following: characteristics • On an RMB795B central control unit, up to 10 individual room groups can be activated or configured • One room group consists of 1 up to (theoretically) 63 rooms •...

  • Page 57: Activate Function Block

    Relay Relay ACS operator station If, in addition to the RMB795B central control unit, an ACS operator station is installed, following applies: and RMB795B central • The operating modes and setpoints of each room controller of a room group can...

  • Page 58: Room Operating Modes Per Room Group

    • Room operating mode selector (preselection under the Room operating mode menu) or Room operating mode via QAW740. • Special day. • Holidays. • Time switch. 58 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Function block: "Room group" 18.01.2012...

  • Page 59: Room Mode Selection Via Digital Inputs

    This function enables the user to make external interventions in the running program (e.g. via switches) without having to make manipulations on the RMB795B central control unit itself. In order to activate this function, you have to configure the appropriate digital inputs.
  • Page 60 This operating mode is active until the signal at the control input is no longer present. Only then does the normal 7-day program resume operation. 60 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Function block: "Room group"...
  • Page 61 It is also possible to configure separate control inputs for holidays and special days. For detailed information, refer to Sec. 8.3.6 "Holidays / special days". Errors in operation The RMB795B central control unit cannot monitor digital signals. 61 / 144 Siemens...

  • Page 62: Room Operating Mode Selection Using Room Unit Qaw740

    Recommendation The potential-free contacts for the digital inputs should be open when in the normal position, enabling the RMB795B central control unit to operate in automatic mode in the event of an open-circuit. 8.3.3 Room operating mode selection using room unit...

  • Page 63: 7-Day Time Switch

    For each "Time switch zone (Apartm)", only one time switch master may be set. If several devices are parameterized as masters, a fault status message occurs. 63 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Function block: "Room group"...

  • Page 64: Holidays/Special Days

    As default, the holiday / special day program of room group 1 is defined as the master, and all other holiday / special day programs as slaves. This means that the settings apply to the entire RMB795B central control unit. If independent holiday / special day programs are required, appropriate...
  • Page 65 7-day program, refer to Sec. 8.3.5 "7-day time switch" under "Setting values"). When the RMB795B central control unit (master) is connected to other devices on the bus (slaves) via communication, a specific 24-hour program (as a special day) can be entered for each of these slaves.
  • Page 66 Holiday input The digital input enables the plant to be constantly switched to "Holiday" mode without necessitating interventions on the central control unit RMB795B. If a permanent signal is applied to the configured input, the plant changes to "Holiday" mode. This operating mode is maintained as long as the signal is present.

  • Page 67: Room Operating Mode Outputs

    If several devices are set as masters, a fault status message occurs. The device, that receives two holiday/special day signals, sends the message. If the RMB795B central control unit expects a holidays/special day signal from the bus and it is not communicated, the following fault status message is sent: "Hol/spec day program failure".
  • Page 68 Synco™200 controller. As the Synco™ 200 controllers do not know operating mode Precomfort, the central control unit RMB795B switches the Synco™ 200 controllers directly to Comfort in the event of Precomfort. This setting can be changed to suit individual needs.

  • Page 69: Functional Check / Wiring Test

    … Comfort cooling setpoint Economy heating setpoint … 19 °C Precomfort heating setpoint comfort heating setpoint Economy heating –50.0 °C... Precomfort 15 °C setpoint heating setpoint 69 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Function block: "Room group" 18.01.2012...

  • Page 70: Application Example, Setpoint Priority, Setpoint Master

    The absolute setpoints can be overwritten locally on the mode room controller during Comfort operating mode. The RMB795B is the setpoint master for all other room operating modes. The absolute setpoints set locally on the room controller are always overwritten again.

  • Page 71: Summer/Winter Compensation

    − 10 °C start − 50.0...+50.0 K Winter compensation delta Troubleshooting If there is no outside temperature sensor signal, the controller does not adjust the setpoint. 71 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Function block: "Room group" 18.01.2012...

  • Page 72: Relate Setpoint Adjustment Using Room Unit Qaw740

    Operating principle The setpoint readjustment via the QAW740 room unit acts on the relevant setpoint readjustments of the RMB room group. From the RMB795B central control unit, the setpoint readjustment is then passed on to the RXB/RXL room controllers of the room group.

  • Page 73: Temperatures "Reference Rooms

    Notes Passing on the setpoints from the RMB795B central control unit to the RXB/RXL room controllers takes place only if, during room group configuration, "Setpoint priority" has been set to "Yes". Additional setpoint readjustments can be made on the RXB/RXL room controller by means of the QAX room unit or the OCI700.1 service tool.

  • Page 74: Optimum Start Control For Individual Room Controllers

    The time switch can thus be set to actual room occupancy. The actual operating period for the plant is significantly reduced resulting in considerable energy savings. 74 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Function block: "Room group" 18.01.2012...

  • Page 75: Activate Function

    Main menu > Settings > Room group 1..10> Optimum start control > Operating line Area Factory setting Boiler setpoint setback 1…600 min/K 30 min/K Room temperature rise 1…600 min/K 30 min/K 75 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Function block: "Room group" 18.01.2012...

  • Page 76: Troubleshooting

    The control function remains active until you manually reset it to "Auto" on the RMB795B. Setting values Main menu > Room group 1…10 > Room operating mode >...
  • Page 77  Cooling must be selected if the control function specification calls for changing over from one control function (e. g. heating) to another control function (e. g. cooling). This does not apply to RDG/RDF/RDU. 77 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Function block: "Room group" 18.01.2012...

  • Page 78: Priorities

    When individual room controllers are used on applications that support the "Night Use and release cooling" function, the room controllers can be released via the RMB795B central control unit. For detailed information about RXB/RXL room controllers that support the "Night cooling"...

  • Page 79: Troubleshooting

    Function In case of emergency, a room group can be switched off via a digital input at an input Xx of the RMB795B central control unit. The signal can be delivered by an external fire alarm system, for example. 79 / 144...

  • Page 80: Activate Function

    Bus telegram to the When individual room controllers are used on applications that support the individual room "Emergency override" function, the RMB795B central control unit can transmit to controllers them via bus the signal for fire alarm off received via the digital input.

  • Page 81: Smoke Extraction

    8.11.2 Operating principle Bus telegram to the When individual room controllers are used on applications that support the "Emergency override" function, the RMB795B central control unit can transmit to individual room controllers them via bus the smoke extraction signal for supply air, extract air or supply air / extract air operation.

  • Page 82: Troubleshooting

    Xx is no longer present, the room group(s) will resume normal automatic operation according to the time program. Fault status messages Text Effect 3880- Smoke extraction Urgent message; must be acknowledged. 3889 82 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Function block: "Room group" 18.01.2012...

  • Page 83: Logic

    • The results from logics A and B act on logic C. • Logic functions AND, NAND, OR, NOR , EXOR or EXNOR can be selected in logic C. Logic Logic Logic 83 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Logic 18.01.2012...

  • Page 84: Activate The Logic

    ---, X1, X2, ... [Logic A] input 3 ---, X1, X2, ... [Logic B] input 1 ---, X1, X2, ... [Logic B] input 2 ---, X1, X2, ... 84 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Logic 18.01.2012...

  • Page 85: Assign Texts

    Depending on type. [Logic B switching value 2] on Depending on selected type Depending on type. [Logic B switching value 2] off Depending on selected type Depending on type. 85 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Logic 18.01.2012...

  • Page 86: Switch-On Delay / Switch-Off Delay

    Display values Main menu > Operation selector 1...10 > Operating line Comments Preselection Auto, Off, On. State Display of the current state: Off, On. 86 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Logic 18.01.2012...

  • Page 87: Wiring Test

    • If outputs are looped back, e.g. from the output of logic block 7 to the input of logic block 2, the result at logic block 2 will only become available with the next handling cycle. 87 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Logic 18.01.2012...

  • Page 88: Application Examples

    [Logic A switching value 1] on 35 °C [Logic A switching value 1] off 65 °C [Logic B switching value 1] on 60 °C [Logic B switching value 1] off 88 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Logic 18.01.2012...

  • Page 89: Application Example Rs Flip-Flop

    Operating line Comments Logic 1 > [Logic A] function Logic 2 > [Logic A] function Truth table for the RS flip-flop: Setting Reset State Save Reset Setting Undetermined 89 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Logic 18.01.2012...

  • Page 90: Function Block: "Faults

    These are fault messages that represent no direct risk to plant operation (e.g. "Outside temp sensor error"). Fault acknowledgement The RMB795B central control unit differentiates between 3 types of fault acknowledgement: None/acknowledge/acknowledge and reset. For details, see Sec. 17.2.2 "Alarm acknowledgement".
  • Page 91 9001 According to the settings (refer to "Setting [Fault inp 1] fault values") 9002 Ditto [Fault inp 2] fault 9003 Ditto [Fault inp 3] fault 91 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Function block: "faults" 18.01.2012...

  • Page 92: External Fault Button

    The fault block allows for connecting an external fault button. The external fault button has the same function as fault button " " on the RMB795B. Both can be operated in parallel. The current alarm state can be externally indicated via the fault relay.
  • Page 93 Under menu item Outputs, the state of the 2 fault relays can be read off: Main menu > Faults > Operating line Current state Fault relay 1 Off, On. Fault relay 2 Off, On. 93 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Function block: "faults" 18.01.2012...

  • Page 94: Functional Check / Wiring Test

    During the time the wiring test is made, the 2 fault relays can be activated directly: Main menu > Commissioning > Wiring test > Outputs Operating line Comments Fault relay 1 Off, On. Fault relay 2 Off, On. 94 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Function block: "faults" 18.01.2012...

  • Page 95: Distribution Zones

    RMH760 in the above illustration). (1) and (2) stand for the distribution zone numbers. Notes This type of application can analogously be applied to refrigeration distribution zones. 95 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Distribution zones 18.01.2012...

  • Page 96: Indirect Application

    Illustration notes With this type of application, the individual RXB/RXL room controllers signal their heat demand indirectly to the heat source via the RMB795B central control unit. This type of application is used for 2 reasons: a) From the RMB central control unit, the heat demand signal is passed on to an...

  • Page 97: Explanation Example 2-Pipe System

    From these signals, a resulting preselected setpoint is determined (temperature request signal, heating flow setpoint, which is passed on to other devices via the “Heat demand" function block. 97 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Distribution zones 18.01.2012...

  • Page 98: Operating Principle

    Heat distribution zone ----, 1…31 11.2.2 Operating principle Request signals The RMB795B central control unit receives the following types of request signals via bus: • Heat demand in %, e.g. from a room control system "RXB/RXL with heating coil" • Valve position in %, e.g.

  • Page 99: Function Block "Heat Demand

    The 3 variants are described below. 11.3.2 Heat demand relay The heat demand relay must be configured to a relay output N.Qx of the RMB795B Purpose and function central control unit. Release for an external refrigeration source, for example, can be connected to this output.

  • Page 100: Heat Demand Modulating

    Setpoint in °C at DC 0 V. here 0 °C (factory setting) Setpoint in °C at DC 10 V. here 120 °C Limit value for heat demand here 10 °C (factory setting) 100 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Distribution zones 18.01.2012...

  • Page 101: Communication

    ----, 1…31 distribution zone 11.4.2 Operating principle Request signals The RMB795B central control unit receives the following types of request signals via bus: • Refrigeration demand in %, e.g. from a room control system "RXB/RXL with cooling coil or chilled ceiling"...
  • Page 102 This setting does not ensure that the refrigeration demand of all consumers can be satisfied. However, in ensures that an individual consumer cannot force the flow temperature to a low level (e.g. because a window is open). 102 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Distribution zones 18.01.2012...

  • Page 103: Refrigeration Demand" Function Block

    Purpose and function The refrigeration demand relay must be configured to a relay output N.Qx of the RMB795B central control unit. Release for an external refrigeration source, e.g., can be connected to this output. The refrigeration demand relay responds as soon as the bus requests refrigeration.

  • Page 104: Communication

    11.5.5 Functional check / wiring test Purpose For making a functional check during the wiring test, the outputs of the "Refrigeration demand" function block can be switched directly. 104 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Distribution zones 18.01.2012...

  • Page 105: Function Block "H/C Changeover

    When the function block has been activated and a "H/C changeover input" has been defined, the RMB795B central control unit can pass on via bus the external changeover signal received via a digital input Xx to the RXB/RXL room controllers.

  • Page 106: Activate Function

    H/C changeover input ---, N.X1, N.X2, ... / If an analog input signal is used to generate the changeover signal, two limit values must be selected for changeover. 106 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Distribution zones 18.01.2012...

  • Page 107: Operating Principle

    Example of plant The plant diagram below shows a "2-pipe heating/cooling system" with heat and refrigeration generation. The diverting valve is switched over with a manual switch: 107 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Distribution zones 18.01.2012...

  • Page 108: Lock Time

    11.6.6 Display current state The current state is displayed in menu "Heating/cooling changeover": Main menu > H/C changeover Operating line Comments 2-pipe heating /cooling Heating / cooling system 108 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Distribution zones 18.01.2012...

  • Page 109: Heating/Cooling Ch'over Relay

    Text Effect Fault status message 5802 >1 Heating/cooling Non-urgent message; must be acknowledged changeover signal 109 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Distribution zones 18.01.2012...

  • Page 110: Volume Flow Balancing Vav

    Failure to comply with these items may result in damage to the aggregates and plant parts! All volume flow controllers assigned to room groups 1-10 are controlled if RMB795B triggers the function. Forced control Main menu > Air flow balancing >...
  • Page 111 A fault message "Smoke extraction" or "Fire" can be triggered on other decentralized air handling units (e. g. RMU7x0 GT-A) during simulation if the time switch program is received by the RMB. T’swi Slave (Apart.) corresponds to a room group zone for the RMB795B. 111 / 144 Siemens...

  • Page 112: Communication

    See data sheet N3127 (KNX bus) or basic documentation CE1P33127en (KNX communication) for more information. If there is no bus supply, fault message "No bus power supply" appears. 112 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Communication 18.01.2012...

  • Page 113: Room Group 1

    QAW zone (Apart.) 1...126 ---- "Holidays / special Only 1 QAW740 room unit per room group can be defined. For details, see Sec. 8.3.6 "Holidays/special days". days" menu item 113 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Communication 18.01.2012...

  • Page 114: Distribution Zones" Menu Item

    • The setting "Master" means that the central control unit RMB795B sends, at the beginning of the switching period, and then cyclically at 15-minute intervals, the holidays/special days operating data via the KNX bus.
  • Page 115 • Universal inputs, digital and analog outputs of the RMB795B can be used as Function principle send objects (to the send zones). • Universal inputs of the RMB795B can be used as receiving objects (in the receiving zones). • The data is exchanged as if the device terminals were hardwired.
  • Page 116 (Section 7.1.4). Example 1 The air quality value for an air quality sensor is available on one RMB795B (device 1). This value is sent as a transmission object via an analog input and processed by an RMB795B (device 2).
  • Page 117 Example 2 A RMB795B logic output wants a second device to be made available as release command. A release command generated in device 1 is sent as transmission object via a digital output. Device 2 uses this command to start the rooftop fan.
  • Page 118 "[...X...] sensor error" is sent after a period expires (ca. 30 minutes). Text Effect Fault status messages 5902 >1 identical LTE zone Non urgent message; must not be acknowledged. 118 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Communication 18.01.2012...

  • Page 119: Rxb/Rxl Operation

    Actual value room temp Actual value room temp Present setpoint Economy cooling setpoint Precomfort cooling setpoint Comfort cooling setpoint Comfort heating setpoint Precomfort heating setpoint Economy heating setpoint 119 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies RXB/RXL operation 18.01.2012...

  • Page 120: Special Features Of Setpoint Readjustment

    R = read, W = write 14.2 Special features of setpoint readjustment In the case of RMB795B As can be seen from the "Display values" table, the setpoints for Economy, setpoint priority Precomfort and Comfort can also be directly overwritten.

  • Page 121: Data Acquisition

    Two trend channels can be displayed per Trend view: Primary channel plus extra channel as a reference. It is possible to record signals from local inputs of the central control unit RMB795B as well as room temperatures and outside temperature via bus.

  • Page 122: Trend Function Settings

    The trend channels are displayed with their assigned text. If a trend channel is selected, the display immediately switches to the 24-hour view. The press-and-turn button allows you to navigate between the different views. 122 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Data acquisition 18.01.2012...

  • Page 123: Troubleshooting

    Power failure or restart After a power failure or when leaving the "Extra configuration" menu (fresh start of the central control unit RMB795B), the values of the 8-hour and 8-minute view will be deleted. However, the values of the 24-hour view and those of the last 6 days are retained.

  • Page 124: Activate Meters

    15.2.4 Overflow value The overflow value ensures that the reading on the display of the connected meter is the same as that on the RMB795B. The value at which the meter’s display returns to 0 can be set. 124 / 144...

  • Page 125: Setting And Resetting Meter Readings

    Factory setting Meter 1…4 Max. 20 characters. Meter 1…4 Refer to section 6.5.4 for an overview of all editable texts and on how to reset them. 125 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Data acquisition 18.01.2012...

  • Page 126: Troubleshooting

    Restart occurs after exiting the "Extra configuration" menu or after power failure. Pulses received between the last storage operation and the restart are not counted. 126 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Data acquisition 18.01.2012...

  • Page 127: Device Supervision

    • Detecting the failure of 1 or several room controllers The individual room controllers are queried on a regular basis as per the generated device list. If the RMB795B central control unit does not receive a reply, it will generate a fault status message.

  • Page 128: Read Device List

    The "Create" command is used to generate a complete device list. For that, a search is made on the KNX bus aimed at finding individual room controllers that have the same "Geographical zone (apartment) When the RMB795B central control unit receives a reply from an individual room controller, it is entered on the device list.

  • Page 129: Fault Status Messages

    Main menu > Settings > Room group 1...10 > Device supervision> Operating line Range Factory setting Device supervision 20 characters Device supervision room grp X R’g. X 129 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Device supervision 18.01.2012...

  • Page 130: Help In Case Of Faults

    4593 Device supervision room grp 10 Ditto 4920 RXB/RXL room temperature frost Triggered by a RXB/RXL room controller. No impact on central control unit RMB795B. It only displays the fault. 4930 RXB/RXL room temperature Ditto condensation 4940 RXB/RXL outside air frost...

  • Page 131: Troubleshooting

    [Fault inp 1] fault 17.2 Troubleshooting 17.2.1 Fault indication Fault status messages delivered to the RMB795B central control unit are indicated Significance of fault status messages by the LED in the fault button. This button can be used to acknowledge fault status messages.

  • Page 132: Alarm Acknowledgement

    The fault status message shall be reset only after the fire alarm has disappeared. Note Fault status messages of other devices cannot be acknowledged on the RMB795B central control unit. 17.2.3 Delete fault status messages Function The operator unit allows for deleting the fault history list at the service level via operating line "Delete faults":...

  • Page 133: Troubleshooting

    The geographical address (apartment) of the relevant room group must be the same for the RMB795B central control unit and individual room controllers. In addition, the time switch zone slave (room) must be set to 1 (fixed), and all settings of the subzones must be set to 1 (fixed).

  • Page 134: Electrical Connections

    Electrical connections 18.1 Connection rules Terminal connection The following illustration shows the terminal base of the RMB795B central control concept unit including the connections: • Extra low-voltage side at the top • Mains voltage side at the bottom Passive sensor /...

  • Page 135: Connection Terminals

    18.2 Connection terminals 18.2.1 Central control unit RMB795B RMB795B X2 M G1 X3 M X4 M G1 X5 M X6 M G1 G0 G1 Y1 G0 G1 Y2 G0 G, G0 AC 24 V rated voltage AC 24 V power supply for active sensors, signal sources or limiters...

  • Page 136: Appendix

    19.2 Configuration diagram 19.2.1 Explanation of configuration principle Configuration diagram, The RMB795B central control unit has a large number of preconfigured function contents blocks integrated. The available configuration options are shown in the configuration diagrams; they include: • Input identifiers (inputs, input functions).

  • Page 137: Overview Of Function Blocks

    • Each output terminal can be used only once (e.g. N.Q1 for the fault relay) 19.2.2 Overview of function blocks The following pages provide an overview of the function blocks for the RMB795B Introduction central control unit, including a brief description. For the number of function blocks and the assignment of inputs and outputs, refer to the configuration diagram of the RMB795B.
  • Page 138 Calendar functions • Holiday and special day input: Digital input for holidays (settable room operating mode) or special day (special day program of time switch). 138 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Appendix 18.01.2012...
  • Page 139 • Refrigeration demand relay for passing on the refrigeration demand. (relay Q) • Refrig demand modulating • Refrigeration demand modulating for passing on the heat demand by means of analog DC 0…10 V signal. 139 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Appendix 18.01.2012...

  • Page 140: Configuration Diagram Rmb795B

    19.2.3 Configuration diagram RMB795B Empty configuration diagram of basic type “B”: 140 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Appendix 18.01.2012...

  • Page 141: C3127_Planning And Commissioning Protocol

    C3127_Planning and commissioning protocol Purpose To ensure successful planning of KNX communication between the RMB795B central control unit and the RXB/RXL room controllers or RDG/RDF/RDU room thermostats, a Planning and Commissioning Report has been made available. It is used to straightforwardly list and document all settings required for communication.
  • Page 142 Function............129 Digital inputs (Xx) ..........50 Display contrast ............ 42 Texts..............55 Display meter readings ........127 Universal inputs (Xx)......... 44 Distribution zones, applications ......97 142 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Index 18.01.2012...
  • Page 143 Planning and commissioning protocol ..24, 143 Product documentation......... 13 Product range ............10 Pulse..............52 Universal inputs Pulse valency............126 Cause..............45 Reference rooms ..........74 Wiring test .............34 143 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies Index 18.01.2012...
  • Page 144 Siemens Switzerland Ltd Sector Infrastructure & Cities Building Technologies Division Gubelstrasse 22 6301 Zug Switzerland Tel. +41 41-724 24 24 © 2012 Siemens Switzerland Ltd www.siemens.com/sbt Subject to change 144 / 144 Siemens Central control unit RMB795B CE1P3122en Building Technologies...

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