PLC (Programmable Logic Controllers) may now be enabled to run irrigation using 2wire decoders. This is useful where the PLC is already doing control, like waste-water or pumping, but irrigation or water spreading is also needed. With Irrigation added, it can then be incorporated into SCADA.
Currently, to control irrigation, multi-wire outputs (usually relay) need to be added to the PLC, with a pair of wires to each 24VAC solenoid in the valve. This is an expensive option. Now a single pair of wires with a ‘decoder’ connected to each solenoid will do the same thing. A serial output (RS232) or a Modbus RTU port (RS485) from the PLC is all that is needed to connect to the TWL BT2. This then acts as a gateway to the decoders. Up to 127 decoders may co-exist on the same 2wire path.
No protective grounding is needed along the 2wire path, just one next to the BT2. TWL’s decoders are warranted for 5 years including damage from lightning.
For more information, please contact Tony Ware: +44 7595 894484 or tony@twl-irrigation.com
