Monroe Electronics Electrostatic Fieldmeter - Static Monitor - model 177A - Manual (Page 48)

47
APPENDIX IV
Communication with ME 177A using MODBUS Protocol
Read Channel LEDs or Relays (read coil)
Write Channel LEDs or Relays (write coil)
Read Channel display (read register)
Write Channel display (write register)
Read Channel LEDs or Relays (read-coil):
From Master (PC software or PLC):
Unit# Command CoilAdrH CoilAdrL lenHigh lenLow crcH
crcL
1-255 0x01 0 0-24 0 1
The request consisted of the unit# and the command code 01 followed by a 2 byte starting address,
specifying the variable to be read.
Length high must be 0, length low is 1.
CoilAdrH is 0
CoilAdrL is as follows:
0 Channel 1 Alarm (red) LED
1 Channel 2 Alarm (red) LED
2 Channel 3 Alarm (red) LED
3 Channel 4 Alarm (red) LED
4 Channel 1 Warning (Amber) LED
5 Channel 2 Warning (Amber) LED
6 Channel 3 Warning (Amber) LED
7 Channel 4 Warning (Amber) LED
8 Channel 1 OK (Green) LED
9 Channel 2 OK (Green) LED
10 Channel 3 OK (Green) LED
11 Channel 4 OK (Green) LED
12 Channel 1 Alarm Relay
13 Channel 2 Alarm Relay
14 Channel 3 Alarm Relay
15 Channel 4 Alarm Relay
16 Channel 1 Warning Relay
17 Channel 2 Warning Relay
18 Channel 3 Warning Relay
19 Channel 4 Warning Relay
20 Channel 1 OK Relay
21 Channel 2 OK Relay
22 Channel 3 OK Relay
23 Channel 4 OK Relay
24 System Alarm Relay