9
Bus structure
9.1
Overview of the bus structure
The VariPro controller is equipped with RS-485 interfaces. The controller uses a
Modbus RTU protocol, and, in total, 125 controllers can be connected to one
branch.
Figure 2: Operating principle of the bus structure
1. Main control interface
2. Ethernet (TCP/IP network)
3. Gateway
4. Max 9 units
5. Modbus RTU (RS-485) Max 125
controllers
A
First floor
B
Ground floor
Note! Observe proper delays when communicating over Modbus. Use a polling
delay of at least 200 ms. If you observe bus errors, increase the delay until there are
no errors. Continuously rewrite (refresh) the desired control registers at least every
5 minutes.
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VariPro Room controller – Installation and Operation Manual
