Modbus Communication - Honeywell 700 User Manual

HONEYWELL MODEL 700/800 SIGNAL PROCESSOR AND VIEWING HEAD

MODBUS COMMUNICATION

The 700ACSP and 700DCSP signal processors are capable
of communication with Flametools software running on a
Microsoft ® Windows ® PC, S7999D touch 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 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
Register Name
40001 FLAMECOUNT
40002 PROCSTATUS
40003 FLAMEON
40007 OUTPUTGAIN
40010 IRGAIN
40012 UVTGAIN
40017 TYPE
40021 TIMEDELAY
40022 FFRT
40023 VERSION
40024 MODEL
66-2069EP—04
Table 4. MODBUS registers map.
Description
Flame count of active viewing head (read only)
Processor status bitmask (read only)
bit 1: flame on relay status (1=relay energized, 0=off)
bit 2: Processor Lockout status (0 =lockout, 1=not lockout)
bit 3: Panel access disabled (1=disabled, 0=enabled)
bit 4: 4 - 20 ma output (0=0 to 20, 1=4 to 20)
Flame On setpoint (read/write)
Gain of the 0/4-20mA output (read/write)
IR sensor gain setting (read/write)
UV tube gain setting (read/write)
Viewing head type bitmask (read only)
bit 0: UV viewing head
bit 1: IR viewing head
Time Delay (read only)
=1 for 700XXSP
Flame failure response time setting in seconds (read/write)
Firmware version (read only)
Model number (read only)
NOTE: Default protocol must be changed in order to use
Modbus communication. It may be set for Modbus 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
connected to the RS-422 bus, their individual
Modbus addresses must be set to differing values
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
seconds 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.
16
Minimum Maximum
0 3425
0 255
3 (S70X) 29
20 80
1 9
1 9
- -
1 2
1 3
- -
- -