Issue
Clarifying the differences between Crompton and Modbus protocols when configuring IC Modbus networks, especially when integrating slave devices.
Product Line
Satchwell BAS & SigmaEnvironment
- Sigma IC3-Modbus
- Sigma IC-Modbus
Cause
Confusion arises when attempting to add Modbus slave devices to a network where IC Modbus is configured for Crompton. The two protocols handle data registers differently, which can lead to incompatibility.
Resolution
The key differences between Crompton and Modbus protocols lie in how they handle data registers:
-
Modbus Mode:
- Reads 16-bit registers individually.
- Can combine two consecutive 16-bit registers to form a 32-bit word.
- Suitable for standard Modbus slave devices.
-
Crompton Mode:
- Reads a single 32-bit register directly.
- Crompton devices inherently use 32-bit registers.
Because of these differences:
- Modbus and Crompton slave devices cannot be mixed on the same IC Modbus network.
- Ensure the IC Modbus configuration matches the register format of the connected devices.
Best Practices
- Always verify the register format of slave devices before configuring the IC Modbus.
- Use separate networks or gateways if both Crompton and Modbus devices are required in the same system.
