STATUS SCIENTIFIC CONTROLS
Installation, Commissioning & Routine Gas Testing
FGD10A-M Gas Detector
TD18/032
Issue:
10
Change Note:
1869
Page 65
Typical Network operating parameters
Slave response timeout
2000 (ms)
Turnaround delay
2000 (ms)
Message to message delay
10 (ms)
Number of retries
2
10.2. Modbus Register list.
Note:
16 bit hexadecimal notation is represented by: 0x000A =10 decimal
R/W = READ/WRITE access
MSB/LSB: most/least significant byte
INT16 = signed 16 bit integer
uINT16 = unsigned 16 bit integer
MSFP16 = Most sig. 16 bits of IEEE574 32 bit floating point number
LSFP16 = Least sig. 16 bits of IEEE574 32 bit floating point number
RTC= Real Time Clock
Modbus register notation:
The memory ma
p used is the “read holding register” map (command 0x03H)
Starting from logical address 40001. This corresponds to physical address
0x0000
More detailed examples are given below.
Some registers e.g. gas reading are read only. Other registers have full
read/write access.
Zero and span are achieved by writing any value to the appropriate register.
Note: zero and span are not allowed via a broadcast message.
LOGICAL
ADDRESS
(R/W)
DATA
TYPE
DESCRIPTION
40001
R
INT16
GAS READINGx10
e.g. 0x01F4=500= 50%LEL
40002
R
uINT16
FAULT STATUS
FGD10A fault code Returns the bitwise
OR of any of the following fault
conditions:
0x0000 normal operation
ERROR_CSUM = 1,
ERROR_SENSOR_NEG_DRIFT = 2,
ERROR_SENSOR_ZERO = 4,
ERROR_SENSOR_SPAN = 8,
ERROR_SENSOR_NO_COMMS = 16
