How to wire the control inputs on a 3 phase application:

The Power-io DC control inputs can be wired in series or parallel. PLC installations are usually 24 VDC outputs. Wiring the Power-io units in series, keeps the milliamp requirements low. This will minimize the stress on the PLC.

Many stand-alone temperature controllers have an 18 VDC logic output @ 15-25mA. The Power-io units can be wired in series or parallel in these applications.

Some low-priced temperature controllers, or micro controllers, such as an Arduino, only have a 5 VDC output. The Power-io should be wired in parallel, and the controller needs to confirm that they can provide about 24mA.