Gill Instruments Ltd
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MaxiMet
Page 47
Issue 1
Doc. No. 1957-PS-000x
March 2015
6.6.
Configuring MaxiMet for MODBUS
MaxiMet Supported Modbus Specification
MODBUS
RTU or ASCII.
Baud Rate
9600 or 19200 Baud.
COMMS
RS232 point to point only, RS485 2 wire networkable.
Modbus Parameters ASCII or RTU.
Parameter
Modbus ASCII
Modbus RTU
Character
ASCII 0 to 9 and A to F (Hex)
Binary 0 to 255
Error Check
Longitudinal Redundancy Check
(LRC)
Cyclic Redundancy Check
(CRC)
Frame Start
Character ':' (3A Hex)
3.5 Characters Silence
Frame End
Characters CR/LF (0D/0A Hex)
3.5 Characters Silence
Gaps in
Message
1 Second
1.5 Times Character Length
Start Bit
1
1
Data Bits
7
8
Parity
Even/Odd
None
Even/Odd
None
Stop Bits
1
2
1
2
Requires:-
MaxiMet.
MetSet Software.
Connect a MaxiMet to a PC COM port (default communication is RS232).
Open Gill MetSet Software.
Click on Connect and Read to reach the Editing Pages as shown below.
Configuration
Click on the MODBUS Page
Mode:
Choose between RTU and ASCII, in this case RTU.
Address:
Choose a MaxiMet Address number between 1 to 247.
Data Bits:
Choose 7 for Modbus ASCII and 8 for Modbus RTU.
Stop Bits:
Choose 1 for Even/Odd Parity or 2 for No Parity (None).
Parity:
Choose Even/Odd or None.
Termination Char ASCII code:
Choose between 0-255.
Inter Char Timeout (ms):
Choose between 500ms to 10000ms.