Proportion-Air is pleased to introduce electro-pneumatic pressure control and flow control valves equipped with the Modbus Serial bus. The serial communications capability is now available on the popular QBT, QPV, and QB3 series of pressure control valves which operate as Modbus slaves. The Proportion-Air valves have the following advantages.

•  The control valves come from the factory with both the RS232 and RS485 electrical interfaces which are selectable with a DIP switch.

• The Modbus protocol is not a proprietary protocol but an industrial serial standard. (modbus-dia.org)   

• When compared with analog devices, a Modbus network reduces the amount of cabling and eliminates analog input output cards. For example, both the command and monitor signals are transmitted through the same two wires.

• The Proportion-Air Serial devices have a choice of four baud rates which are selectable with DIP switches.