26
APPENDIX 2
Modbus Register Specification for 16 cCAN system
Function code 03 used througout to access these 16 bit unsigned registers
Baud rate 4800,9600,19200
No parity
1 stop bits
2 channel known as Duty and standby (RS485)
Register definition
Data
Units
0
watchdog counting
Integer
none
int 250 usec counter
4-20 chan
1 to 16
integer
Gas value * 10
as per 17 to 32
4-20 chan
17 to 32
gas 1-16 units
see gas number table
units
will have zero for unused
4-20 chan
33
low alarm bits
1-16 channel
1=alarm (bit 0 is chan 1 etc)
4-20 chan
34
high alarm bits
1-16 channel
1=alarm (bit 0 is chan 1 etc)
4-20 chan
35
overange alarm bits
1-16 channel
1=alarm (bit 0 is chan 1 etc)
4-20 chan
36
Sensor fail
1-16 channel
1=alarm (bit 0 is chan 1 etc)
Can Chan
40 to 104
integer
Gas value * 10
as per 105 to 168
Can Chan
105 to 168
gas 1-64 units
see gas number table
units will have zero for unused
Can Chan
169
low alarm bits
1-16 channel
1=alarm (bit 0 is chan 1 etc)
Can Chan
170
low alarm bits
17-32 channel
1=alarm (bit 0 is chan 17 etc)
Can Chan
171
low alarm bits
33-48 channel
1=alarm (bit 0 is chan 33 etc)
Can Chan
172
low alarm bits
49-64 channel
1=alarm (bit 0 is chan 49 etc)
Can Chan
173
high alarm bits
1-16 channel
1=alarm (bit 0 is chan 1 etc)
Can Chan
174
high alarm bits
17-32 channel
1=alarm (bit 0 is chan 17 etc)
Can Chan
175
high alarm bits
33-48 channel
1=alarm (bit 0 is chan 33 etc)
Can Chan
176
high alarm bits
49-64 channel
1=alarm (bit 0 is chan 49 etc)
Can Chan
177
over range alarm bits
1-16 channel
1=alarm (bit 0 is chan 1 etc)
Can Chan
178
over range alarm bits
17-32 channel
1=alarm (bit 0 is chan 17 etc)
Can Chan
179
over range alarm bits
33-48 channel
1=alarm (bit 0 is chan 33 etc)
Can Chan
180
over range alarm bits
49-64 channel
1=alarm (bit 0 is chan 49 etc)
Can Chan
181
Sensor fail/timeout
1-16 channel
1=alarm (bit 0 is chan 1 etc)
Can Chan
182
Sensor fail/timeout
17-32 channel
1=alarm (bit 0 is chan 17 etc)
Can Chan
183
Sensor fail/timeout
33-48 channel
1=alarm (bit 0 is chan 33 etc)
Can Chan
184
Sensor fail/timeout
49-64 channel
1=alarm (bit 0 is chan 49 etc)
Service Days
185
Service days remaining
Integer
Days
4-20 Chan
191
Inhibit
1-16
CAN Chan
192
Inhibit
1-16
CAN Chan
193
Inhibit
17-32
CAN Chan
194
Inhibit
33-48
CAN Chan
195
Inhibit
49-64
222
System status
bit 0 = global sensor fail
bit 1 = spare
bit 2 = system fault
bit 3 = battery power lost
bit 4 = main power lost
bit 5 =
bit 6 =
bit 7 =
bit 8 = modbus comms fail
bit 9 = l
bit 10 = CAN bus fail
bit 11 = spare
bit 12 = spare
bit 13 = spare
bit 14 = spare
bit 15 = spare
Can Addresses
1 to 64
Can Sensors
65 to 128
Reserved for more
129 to 200
Spare
201 to 209
Panels (default=201)
210 to 255
Spare
Additional Modbus Commands
(only available on modbus 1)
Byte 1
Byte 2
Byte 3
Byte 4
Byte 5
Byte 6
Byte 7
Byte 8
Decimal
ascii symbol
ascii
Adddress
Function
Code
direct/
addr/panel
Spare
CRC
CRC
Definition
201
6
*
1 to
0
D
xx
xx
disable addressable detector 1 to 64
201
6
*
1 to
0
E
xx
xx
enable addressable detector 1 to 64
201
6
:
1 to
0
d
xx
xx
disable direct 4-20mA detector 1 to 16
201
6
:
1 to
0
e
xx
xx
enable direct 4-20mA detector 1 to 16
201
6
*
1 to
0
I
xx
xx
inhibit addressable detector 1 to 64
201
6
*
1 to
0
N
xx
xx
NOT inhibit addressable detector 1 to 64
201
6
:
1 to
0
i
xx
xx
inhibit direct 4-20mA detector 1 to 16n
201
6
:
1 to
0
n
xx
xx
NOT inhibit direct 4-20mA detector 1 to 16
201
6
!
0
0
R
xx
xx
Reset Panel
201
6
!
0
0
A
xx
xx
Accept alarm (buzzer off)
201
6
repeat
repeat
0
repeat
xx
xx
Command accepted
201
2
0
crc
crc
Detector out of range
201
1
0
crc
crc
illegal command
Note: default address is 201 (C9 hex) This can be changed. Ascii uppercase is use to reference addressable detector commands.
Ascii lowercase is used for direct 4‐20mA detector commands. Asci ! is used for panel commands. Function code 6 is write single register
command and is used for all commands. CRC is 16bit cyclic redundancy check.
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