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RKI M2A Operator's Manual

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65-2643RK-05-04
M2A Transmitter
Operator's Manual
Part Number: 71-0387
Revision: 0
Released: 11/28/17
RKI Instruments, Inc.
www.rkiinstruments.com

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  • Page 1 65-2643RK-05-04 M2A Transmitter Operator’s Manual Part Number: 71-0387 Revision: 0 Released: 11/28/17 RKI Instruments, Inc. www.rkiinstruments.com...
  • Page 2 Frequency of calibration depends upon the type of use you have and the sensor types. Typical calibration frequencies for most applications are between 3 and 6 months, but can be required more often or less often based on your usage. 65-2643RK-05-04 M2A Transmitter Operator’s Manual...
  • Page 3 Product Warranty RKI Instruments, Inc. warrants gas alarm equipment sold by us to be free from defects in materials, workmanship, and performance for a period of one year from date of shipment from RKI Instruments, Inc. Any parts found defective within that period will be repaired or replaced, at our option, free of charge.

  • Page 4: Table Of Contents

    Viewing & Changing M2A Parameters ........
  • Page 5 Using the M2A in a 4-wire Modbus System ....... 41...

  • Page 6: Chapter 1: Introduction

    The M2A displays the current gas reading on an OLED display which is visible through the window in the cover (front face) and provides a 4 - 20 mA signal which indicates the target gas reading for use by a gas monitoring controller, recording device, or programmable controller.

  • Page 7: Specifications

    -20°C to 45°C Accuracy ± 0.5% O These are the RKI factory settings. You can change the alarm settings in Configuration Mode. See “Viewing & Changing M2A Parameters” on page 23. WARNING: When using the M2A, you must follow the instructions and warnings in this manual to assure proper and safe operation of the M2A and to minimize the risk of personal injury.

  • Page 8: Chapter 2: Description

    Chapter 2: Description Overview This chapter describes the components of the M2A transmitter. The transmitter is a 4 - 20 mA type detector head. It consists of the oxygen detector, calibration adapter/splash guard, terminal PCB, the M2A junction box, and the detector junction box. The two- junction-box configuration is intended for situations where the detector needs to be installed at an inaccessible location.
  • Page 9 The M2A’s cast aluminum junction box is dust and weather resistant. The junction box also protects the M2A and all connections made to it. Use the three 3/4 in. conduit hubs to mount the detector to the junction box (factory installed in the bottom hub) and connect wiring from an external device (left hub).
  • Page 10 (near the M2A junction box is optimal for ease of calibration). The calibration adapter/splash guard also protects the detector from splashing water or direct water spray.

  • Page 11: Internal Description

    This section describes the internal components of the M2A. The internal components of the M2A include the terminal PCB which provides for all the wiring connections to the M2A and the control PCB which displays the gas reading and has the control buttons.
  • Page 12 The power/signal terminal strip is a three position plug-in style terminal strip located at the top of the left terminal column. It is used to connect 24 VDC power to the M2A and to connect the 4 - 20 mA output signal to a device.
  • Page 13 A two pin header with a jumper installed is located along the left side of the terminal PCB. Leave this jumper installed unless directed to remove it for a Modbus installation. See “Chapter 8: RS-485 Modbus Output” on page 37 for a description of using the M2A in a Modbus system.
  • Page 14 The M2A includes five status LEDs that are located above the display (see Figure 5). • Fail LED The fail LED turns on when the M2A is experiencing a fail condition. A fail condition can be caused by a detector failure or low detector signal. •...

  • Page 15: Chapter 3: Installation & Startup

    • For the M2A junction box, select a site where the junction box is not likely to be bumped or disturbed. Make sure there is sufficient room to perform start-up, maintenance, and calibration procedures. The site should be easily accessible.
  • Page 16 Install 3/16 inch I.D. flexible polyurethane tubing to the fitting at the bottom of the calibration adapter/splash guard and route it to an accessible area that is close to the M2A junction box. See the “Parts List” on page 48 for available tubing. 65-2643RK-05-04 M2A Transmitter Operator’s Manual...

  • Page 17: Wiring The M2A Transmitter

    Wiring the M2A Transmitter WARNING: Always verify that the power to the M2A is off before you make wiring connections. Confirm that no power is being applied to the M2A. Remove the detector junction box’s cover from the junction box.
  • Page 18 CAUTION: If shielded cable is used, leave the cable shield’s drain wire disconnected and insulated at the detector junction box. You will connect the opposite end of the cable’s drain wire to the M2A junction box’s chassis (earth) ground. Cable...
  • Page 19 M2A is wired to a gas monitoring controller or just to power, whether any relays are used, and whether the Modbus output is used. If the M2A is being wired to a PLC or DCS device, see “Appendix B: PLC and NOTE: DCS Device Wiring”...

  • Page 20: Start Up

    If necessary, turn on the controller or other monitoring device that is connected to the M2A. The OLED display will indicate the firmware version when the M2A is first powered up and will then count down a one minute warm-up period before normal operation begins.
  • Page 21 To actuate a magnetic switch and perform the same operation as pressing a control switch button, touch the magnet in the end of the magnetic wand to the M2A’s glass cover directly over the magnetic switch you wish to actuate. Touching the glass and removing the wand is the same as pressing and releasing a button.
  • Page 22 Press and release the ENTER button. The M2A will perform a span operation and then the display will indicate ZERO w/Cal Gas?. Press and release the DOWN/NO button. The display will indicate Leaving CAL Mode and the M2A will return to normal operation.

  • Page 23: Chapter 4: Operation

    Continue holding the DOWN/NO button to keep the Information Screen on the display. The top line indicates the operating voltage that is connected to the M2A. The second line indicates the firmware that is running, version 5.0 in this example, and the M2A’s hardware version, version 2A in this example.

  • Page 24: 4 - 20 Ma Signal Output Operation

    Mode, the signal output will be fixed at 17.4 mA until the M2A returns to normal operation. • If the M2A’s input power decreases below 9.5 volts so that the M2A is in a low power alarm, the signal output is fixed below 2.4 mA until the low power alarm is cleared. •...
  • Page 25 • LowPower message and actual voltage of incoming DC power If the M2A is in both an alarm 1 and an alarm 2 condition, both alarm LEDs are on and the display alternates between the gas reading and the ALMS 1&2 message. NOTE: You can select normally energized (N.
  • Page 26 The gas reading alternates with the ALARM-2 message. • The alarm 2 relay energizes. If the M2A is in both an alarm 1 and alarm 2 condition, both the A1 and A2 NOTE: LEDs will be on, the gas reading will alternate with the ALMS 1&2 message, and both alarm relays will energize.
  • Page 27 Low Power Alarm Low Power Alarm Indications The M2A senses a low power condition when the DC power source is 9.5 volts or less. WARNING: While in a low power condition, the M2A is not an active gas monitor. When the M2A senses a low power condition, it alerts you as follows: •...

  • Page 28: Chapter 5: Configuration Mode

    If the currently displayed parameter is OK, press the ENTER button to proceed to the next parameter. Table 5 lists the M2A parameters you can set. Table 5 also lists the factory set value for each parameter. 65-2643RK-05-04 M2A Transmitter Operator’s Manual...
  • Page 29 15 minute increments from 15 - 60 minutes. A1 OffDy (alarm 1 off delay) The amount of time the M2A delays turning off the alarm 1 circuit once an (0 sec.) alarm 1 condition passes. This parameter appears only if the alarm 1 relay reset setting is set to SELF-RST.
  • Page 30 Go back to step 3 and continue. If you wish to save the adjustments made, press and release the UP/YES button. Config Saved is indicated on the display for a few seconds and the M2A returns to normal operation.

  • Page 31: Chapter 6: Gas Type Mode

    Chapter 6: Gas Type Mode Overview This chapter describes how to use Gas Type Mode to select the M2A’s gas type. The gas type determines the target gas and detection range. CAUTION: The target gas is factory set and does not normally need to be changed. The standard setting for the 65-2643RK-05-04 is oxygen.
  • Page 32 Gas Type Updated, the display will indicate the target gas and the detection range for a few seconds, and then the M2A will enter Configuration Mode automatically so that the parameter settings in Configuration Mode can be verified or changed.
  • Page 33 11. See “Calibration” on page 33 for calibration instructions. NOTE: When calibrating an M2A after changing the gas type, the M2A will not ask if you want to calibrate, or whether you want to perform a fresh air adjustment zero adjustment. Since a complete calibration is required, the calibration sequence will proceed without asking if you want to perform certain operations.

  • Page 34: Chapter 7: Maintenance

    Response Time” on page 32. Verify that the display reading is within ± 20% of the gas concentration. NOTE: If the reading is not within ± 20% of the gas concentration, calibrate the M2A as described in “Calibration” on page 33.

  • Page 35: Troubleshooting

    11. Store the components of the calibration kit in a safe place. Quarterly Calibrate the M2A as described in “Calibration” on page 33. See “Calibration Frequency” on page 32 for a discussion of calibration frequency guidelines. Troubleshooting The troubleshooting guide describes symptoms, probable causes, and recommended action for problems you may encounter with the M2A.
  • Page 36 Condition Symptom(s) Probable Causes Recommended Action Flickering The display reading • The M2A is 1. Verify that the M2A wiring is experiencing false properly shielded. See “Wiring Display flickers often. readings due to RFI the M2A Transmitter” on page 12.

  • Page 37: Calibration Frequency

    3 months may be necessary. Determining Response Time Since the detector junction box is installed remotely from the M2A, the response time of the detector will depend on the length of flexible tubing that is attached to the calibration adapter/splash guard.

  • Page 38: Calibration

    M2A. When zero air is applied to the M2A during a fresh air adjustment, the M2A will freeze the display reading at the highest response and the M2A will continue to display this reading and retain it in its memory until the fresh air adjustment procedure is completed.
  • Page 39 OXYGEN CAL Mode for a few seconds before showing FreshAir Adjust?. If you want to exit Calibration Mode, press and release the DOWN/NO button. The M2A will indicate Leaving CAL Mode and the M2A will return to normal operation.

  • Page 40: Replacing Components Of The Oxygen Detector

    12% oxygen, set the zero reading to match the cylinder’s oxygen concentration. The M2A will perform a zero operation. The display will indicate ZERO Gas PASS for a few seconds, then indicate ZERO Gas SAVED before indicating Leaving CAL Mode for a few seconds.
  • Page 41 Screw the calibration adapter/splash guard onto the new detector housing cap. Reinstall the detector junction box cover. 10. Turn on or plug in power to the M2A. CAUTION: Allow the replacement detector to warm up for 5 minutes before you continue with the next step.

  • Page 42: Chapter 8: Rs-485 Modbus Output

    Common Ground Jumper The M2A includes a 2-pin ground header (see Figure 4 on page 7) that is used when the M2A is used in a Modbus system. Every M2A is supplied with a ground jumper (a jumper block) installed onto this header. If the M2A isn’t wired into a Modbus system or if it is...
  • Page 43 Figure 11, the ground jumper should be installed. If the M2A is wired in a Modbus system as shown in Figure 10, the ground jumper should be removed. Recommended Modbus Wiring The recommended Modbus wiring for the M2A is illustrated in Figure 10 below. In this configuration, 5 wires are used for wiring the M2A into a Modbus system.
  • Page 44 Adding an M2A to an Existing M2 Modbus Installation with Alternate Wiring An M2A can be wired into an existing M2 Modbus system. The shape of the terminal PCB will be different but the wiring connections are identical and the ground jumper on the M2A must still remain installed.
  • Page 45 When the M2A is installed in a Modbus system, this jumper must be installed in an M2A that is at the end of a Modbus line. Any M2A in a Modbus system that is not at the end of a line must have the termination jumper removed (see Figure 12 &...

  • Page 46: Using The M2A In A 4-Wire Modbus System

    Using the M2A in a 4-wire Modbus System Although the M2A is a 2-wire Modbus RTU device, it can be used with a 4-wire Modbus controller if the system wiring is modified as follows: • Connect the controller’s TxD0 and RxD0 wires together and use this connection as the 2-wire Modbus D0 signal.
  • Page 47 Go back to step 3 and continue. If you want to save the adjustments made, press and release the UP/YES button. Modbus Saved is indicated on the display for a few seconds and the M2A returns to normal operation.

  • Page 48: Supported Modbus Functions

    Supported Modbus Functions The M2A supports Function Code 03: Read Holding Registers and Function Code 16: Write Registers. Function Code 03: Read Holding Registers There are a total of 40 registers available to be read via this Function Code. Registers 1 - 2 The format (bit &...
  • Page 49 Register 3 is the supply voltage (0.1 volt per count). Registers 4 - 11 The 16 bytes in these registers contain the same ASCII text information that is displayed on the M2A’s OLED display (not NULL Terminated). Register 12 Register 12 is the range (full scale readout).
  • Page 50 Register 30 is the alarm 2 relay reset. 0=Latching 1=Self-Resetting Register 31 Register 31 is the alarm 2 ON delay. Integer values are in seconds. Register 32 Register 32 is the alarm 2 OFF delay. Integer values are in seconds. 65-2643RK-05-04 M2A Transmitter Operator’s Manual...
  • Page 51 12=LEL Sensor Offset Is Too High 13=LEL Null Operation Failed 14=Operation Not Performed Register 39 Register 39 is the auto-zero disable. 0=AutoZero Enabled 1=AutoZero Disabled Register 40 Register 40 is the remote configuration register access level 0=None 1=Alarm Reset 65-2643RK-05-04 M2A Transmitter Operator’s Manual...
  • Page 52 Function Code 16: Write Registers There are 21 registers in Function Code 16 that can be used to write to the M2A. This manual only describes Register 16 because it can be used to reset an alarm condition. For a complete description of Function Code 16, request Appendix C from RKI Instruments, Inc.

  • Page 53: Parts List

    Parts List Table 13 lists replacement parts and accessories for the M2A Transmitter. Table 13: Parts List Part Number Description 06-1248RK Calibration kit sample tubing (3/16 in. x 5/16 in.; specify length when ordering) 07-0033RK Detector housing cap gasket 18-0400RK-01...

  • Page 54: Appendix A: Control Button Quick Reference Guide

    Appendix A: Control Button Quick Reference Guide The M2A’s control buttons allow access to operational modes, resetting of alarms, and display of the Information Screen. Table 14 shows which button combinations perform these functions and which parameters are available for adjustment while in the operational modes.

  • Page 55: Appendix B: Plc And Dcs Device Wiring

    If the PWR/SIG terminal strip connections and one or more relays are used, route the connections to the M2A in conduit. Use shielded cable in the conduit for the PWR/SIG connections and unshielded cable or individual wires for the relay connections.
  • Page 56 See Figure 14 below for field wiring connections to the M2A. 24 VDC Power Supply 24 VDC + Alarm Device Power 24 VDC - Fail Alarm Device 4 - 20 mA In (S) (24 VDC) - Alarm 1 Alarm Device...

  • Page 57: Appendix C: Function Code 16 Registers

    Appendix C: Function Code 16 Registers The M2A supports Function Code 16 that allows writing to the M2A. There are 21 registers in this Function Code. Register 1 Register 1 is the alarm 1 set point. Value must be an integer. Any decimals are omitted.
  • Page 58 Register 18 is the calibration year. Register 19 Register 19 is for clearing change flags. When parameters are changed at the M2A, a flag is raised at the controller. This register can be used to clear those flags. Table 16: Register 19, Clear Change Flags Bit(s) Value &...
  • Page 59 Register 20 Register 20 is the AutoZero Disable. 0=AutoZero Enabled 1=AutoZero Disabled Register 21 Register 21 is the Remote Configuration Register. 0=No Remote Configuration 1=Reset Alarm 65-2643RK-05-04 M2A Transmitter Operator’s Manual...

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