Power Considerations

PLC Power

All CLICK CPUs and I/O Modules require 24 VDC power to operate (PLC Power).  If you select the C0-00AC power supply (0.5A) or if you supply your own PLC Power, you should total up the PLC power required by the CPU and any modules you select (see column two of the chart) to verify that you will have enough 24 VDC to operate the PLC.

If you choose the C0-01AC power supply, you don't have to bother with power budgeting - it supplies enough current to power any CLICK CPU and any combination of up to 8 I/O modules (the maximum allowed).

Field Power

All inputs and outputs on a CLICK PLC are optically isolated from the internal power and signals in the PLC to help prevent noise issues. Some CLICK output types require a small amount of Field Power to power the opto-couplers on the outputs. For maximum noise immunity, it is recommended that this power be supplied from the same source as is used to power the field devices. The amount of field power required by the PLC is shown in the third column of the chart. You will need to size the Field Power supply so that it is large enough to power all the field devices AND the current shown here.

Important note: Do not use the same DC power supply for both PLC Power and Field Power, as this will bypass the optical isolation in the PLC, and can allow electrical noise to reach the CPU. The ensuing problems (and possible damage) can be very difficult and time consuming to diagnose.

Power Budgeting Example:

Simply add up the current required for the CPU module, the two option modules, and the C-more Micro, and compare that to the power available from the CLICK Power supply.

In this example, the PLC requires 330mA of 24VDC power. The C0-01AC Power Supply can supply 1300mA, so the PLC Power budget is sufficient.

A separate field power supply is highly recommended and must supply enough current to power ALL the filed devices PLUS 160mA to power the opto-couplers in the PLC (field side).