Modbus Communication - Honeywell 800 Series Manual

Loading Factory Defaults
Fig. 19 shows the flowchart for restoring default values.
Pressing and holding the LOAD FACTORY DEFAULTS
button will result in the values shown in Table 3 being
loaded and stored in EEPROM. During the automatic
setup sequence, if the AUTO SET LED is on when the
LOAD FACTORY DEFAULTS key is pressed, "CF" will be
displayed. Press the LOAD FACTORY DEFAULTS key again
to confirm the change, or press RESET to abort the
change. If the factory defaults are loaded, the AUTO SET
LED will be turned off.
Table 3. S70X/S80X Default Settings
Relay on setpoint
Ratio (%) relay off/relay on
FFRT (Flame Fail Response Time)
0-20mA/4-20mA OPTION
UV/IR Gain
Communication address
Panel Lock
A pattern of key presses will result in the panel being
locked so as to block any changes to the values stored in
the signal processor. With the panel locked, values may be
examined, but the signal processor will not respond to the
STORE key.
The panel should be locked after the setpoints are set.
Contact the factory to obtain the procedure to lock or
unlock the panel.

MODBUS COMMUNICATION

The 700ACSP and 700DCSP signal processors are
capable of communication with Flametools software
®
running on a Microsoft
screen or other device that supports Modbus RTU
protocol. Both Flametools and the S7999D include
graphic user interfaces. Other devices will require the user
to generate an interface. The data transmitted to and from
the 700ACSP/700DCSP is over two twisted pairs that are
differentially driven and received according to the RS-422
standard. Honeywell offers a RS485/422 to USB converter
to use in conjunction with the 700ACSP/700DCSP signal
processors. The Honeywell part number is COMMOD.
Refer to Fig. 8 and Fig. 9 for a typical communication
wiring and addressing scheme as well as the required
wiring of the COMMOD communication converter.
The 700ACSP and 700DCSP signal processors have two
modular phone jacks for RS-422 communications. The
jacks are wired in parallel so that point-to-point cables
can be jumped from unit to unit to interconnect multiple
HONEYWELL MODEL 700/800 SIGNAL PROCESSOR AND VIEWING HEAD
16
50%
1 sec
4-20mA
5
0
®
Windows PC, S7999D touch
Model 700 signal processors. The RS-422 interface IC is a
MAX489. The ICs can drive up to quantity 32, Model 700
signal processors on the same bus.
For communication with external controls or computers,
refer to Table 4 for the Modbus registers map.
Communication Setting
700ACSP and 700DCSP can only communicate via
Modbus RTU protocol, with the following configuration:
• 9600 baud
• 8 data bits
• no parity
• 1 stop bit
NOTE: Default protocol must be changed in order to use
Modbus communication. It may be set for Mod-
bus by using key sequence below at the front
panel of the 700 as follows:
1. Press and hold BNR-OFF SEQ START/END
button for 2 seconds.
2. Press up arrow to change setting from P0 to
P1.
3. Press STORE.
The factory default Modbus address of the 700ACSP and
700DCSP is 0 and must be changed to a number between
1 and 32 to establish communication between the signal
processor and the host control. When more than one
signal processor is in the network, ensure that each signal
processor has a unique Modbus address within the range
of 1 to 32.
Modbus RTU Function Supported
Four Modbus functions are supported:
• 01 Output coil read
• 03 Holding register read
• 06 Preset single holding register
• 16 Preset multiple holding register
NOTES:
— Before Model 700 signal processors are con-
nected to the RS-422 bus, their individual
Modbus addresses must be set to differing val-
ues between 1 and 32.
— The RESET button on front of the 700ACSP or
700DCSP signal processors is used to set the
Modbus address.
— Press and hold the RESET button for two sec-
onds and the current address will appear. It
may be changed with the up or down arrow
keys.
— Pressing the STORE button will store the new
address.
17 66-2069EP—08