Issue
- How are Modbus 64-bit registers calculated in the Modbus limitations on an RP-C?
- Can both RS485 ports be used for Modbus on an RP-C?
Product Line
EcoStruxure Building Operation
Environment
- SpaceLogic RP Controller series
- RP-C Modbus
Cause
- EBO version 2023 introduced 64-bit register support in RP controllers. EBO Webhelp states that an RP-C has a maximum limit of 250 Modbus registers. It is unclear if a 64-bit register is counted as four 16-bit registers or just one register on the Modbus maximum count.
- The RP-C controller has two RS-485 ports, and it is unclear if both ports can be utilized for Modbus simultaneously.
Resolution
- A 64-bit Modbus register is counted as one register in the Modbus maximum register count.
- The RP-C controller has two configurable RS-485 ports that can be used for:
- Sensor bus
- Room bus
- Modbus network
As per EBO webhelp, the controller can host two networks, but only one network of each network type.
