PM 1000288 000 00
Device handbook SIRAX BT5100
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10. Dimensional drawings
11. Interface Defi nition Modbus RTU
SIRAX BT5100 supports Modbus RTU protocol (RS485).
The permissible address range for the BT5100 is between 1 and 247. Broadcast Mode (address 0) is not allowed.
The maximum latency time of an BT5100 is 200ms i.e. this is the amount of time that can pass before the fi rst response character is output.
After sending any query through software (of the Master), it must allow 200ms of time to elapse before assuming that the BT5100 is not going to
respond. If slave does not respond within 200 ms, Master can ignore the previous query and can issue fresh query to the slave.
43,5mm
106,5mm
65,5mm
11.1 Modbus functions
Following code functions are provide:
Function code
Function
Address
03
Read holding registers
40001 to 40040
04
Read input registers
30001 to 30002
16
Presets multiple registers
40001 to 40040
Example of read out measurement
Query:
Device address
Function code
Start address
Nr. of register
CRC
0x01
0x04
0x0000
0x0002
0x71CB
Response:
Device address
Function code
Nr. of databytes
Databytes 0 … 3
CRC
0x01
0x04
0x04
0x4861D2F0
0xE11E
