How Do You Retrofit a Washer Using a CLICK PLC Controller?

The CLICK PLC and C-more Micro Touch washer project reached mostly successful testing, but the machine had not yet been fully tested or installed. The main design risk was wiring around an assumed 120 VAC control circuit before identifying the machine’s actual electrical and mechanical control paths.

Stop guessing at voltage and output compatibility

Do not choose PLC outputs from the expectation that the washer has a conventional 120 VAC control circuit. The project notes describe a possible 24 VDC solenoid system, a transformer marked 26.6 V/550 mA, and motor and master relays with coils marked 21 VDC. Those observations need to be verified in the machine; they are not enough to establish the voltage at every load or prove that a PLC output can drive a coil.

• Do not wire for 120 VAC by assumption. A legacy-style control circuit may not match this machine’s apparent DC controls. Identify each circuit before connecting the PLC.
• Do not select the C0-00AR-D or another output solely because it seems suitable for the expected voltage. Check the actual output type and ratings against each load, including coil voltage and inductive-load requirements.
• Do not use a PLC output as the motor power switch. The project anticipated a heavier relay for the motor. Size the switching device for the motor circuit from the motor nameplate and device ratings; do not infer those ratings from a relay-coil marking.
• Do not build every cycle before proving one. Start with a single basic cycle, then add cycle selection after the machine’s actions and transitions work reliably.

These shortcuts fail because neither PLC output labels nor relay coil labels describe the whole circuit. A coil marking identifies its coil rating, not the load capacity of its contacts or the voltage and current requirements of other components.

Account for the washer’s mechanically coupled pump action

The machine’s agitate cam bar also reverses pump action. While the motor runs in agitation, the pump recirculates wash water through a filter. While the motor runs without agitation, flow reverses: the washer drains with help from a check valve, and the filter is backwashed. For this mechanism, agitation and draining are mutually exclusive states—not two independent outputs that can be switched on together or both disabled while the motor runs.

Represent that relationship explicitly in the control sequence. Define the operating states from the actual machine mechanism, then confirm which electrical device or linkage selects the state. Do not assume that the PLC can independently select agitation and draining just because the HMI can display separate labels. The project account describes a mechanical coupling, so a software design that requests both actions at once would conflict with the machine’s operation.

Map the electrical circuits before connecting the PLC

Obtain the machine schematic if possible. If it is unavailable, trace and document the circuits before changing wiring. Isolate power and use a qualified technician for measurements or work on hazardous voltages. Do not treat the transformer rating or coil markings as a complete schematic.

1. Record the washer’s model and the markings on the motor, transformer, relays, solenoids, switches, and connectors. Photograph wire locations before disconnecting anything.
2. With power isolated, trace each control device to its source, return, and controlled load. Identify motor switching separately from relay-coil control.
3. Determine the actual voltage and polarity at each control circuit using suitable test equipment and a safe test procedure. Confirm whether a circuit is AC or DC rather than inferring it from the component’s appearance.
4. Compare each load’s voltage, current, and type with the PLC output specifications and any proposed interface relay. Check contact ratings for the actual motor or coil load, including inductive switching requirements.
5. Document the existing interlocks and the function of each switch before bypassing, replacing, or changing it. Preserve safety and overflow-protection functions in the retrofit.

The reported transformer marking is 26.6 V/550 mA, and the motor and master relay coils were marked 21 VDC. Those values do not establish that the transformer supplies every coil, that its output is regulated, or that it can supply added PLC or HMI loads. Read the device datasheets and measure the relevant circuits; do not connect a 21 VDC coil to a source based only on a 26.6 V transformer label.

Build and test one basic cycle first

Keep the first PLC program narrow: implement one basic cycle and validate every state against the washer’s actual operation. The project began with this incremental approach, with additional cycles intended to follow after the initial program was refined. A touchscreen recipe or cycle button selects a program; it does not itself prove that the underlying sequence, timing, or outputs are correct.

1. List each cycle step, the condition that advances it, the outputs it commands, and the expected machine response. Use observed machine behavior rather than assumed cam-timer behavior.
2. Define mutually exclusive agitation and drain states for the motor-running portion of the sequence. Include a safe stopped or fault response based on the identified machine circuitry.
3. Implement and bench-test the logic without energizing washer loads. Check transitions, retained states, and what the program does after a stop or power interruption.
4. Test outputs and connected loads in controlled stages, first where possible with loads disconnected or safely isolated, then with the machine supervised through the basic cycle.
5. Only after the basic cycle passes should you add the other cycle selections and shared temperature selection.

The project report says testing was “mostly successful” and that one relatively minor problem remained; it does not describe the problem or confirm completed in-machine commissioning. Treat that as a reminder to record test failures and retest after corrections, not as evidence that a particular fault has a known fix.

Organize CLICK and C-more functions so changes stay manageable

As the program grew, the project assigned C numbers in blocks by function to make the logic easier to manage. Apply the same discipline: reserve documented ranges for cycle selection, state logic, outputs, and shared selections, and keep a current cross-reference between PLC devices and HMI objects. The specific addresses and block sizes must come from the actual program; none are specified here.

The reported HMI layout used function keys for Normal Wash, Delicate, Permanent Press, Rinse Only, and Pre Wash/Soak. Screen 6 handled temperature selection and was common to each function. The programmer also used a dynamic text object. These are interface choices, not proof of the corresponding PLC sequence. Make sure each displayed cycle label matches the selected program, and verify that shared temperature selection reaches every applicable cycle as intended.

Review copied rungs carefully. The project noted that rung comments needed substantial editing after cut-and-paste. Correct comments and labels to match the final logic; misleading documentation makes later troubleshooting and cycle edits slower and riskier.

Compare symptoms with the next diagnostic check

Verify the installed cycle before returning the washer to service

Do not treat a good-looking ladder program or successful HMI navigation as a completed machine test. Confirm electrical compatibility, safe switching, and the physical sequence under supervision. Verify that the machine fills, agitates/recirculates, drains/backwashes, and stops as intended for the programmed cycle; validate temperature selection and each added cycle separately.

• Check that PLC outputs and interface devices remain within their ratings during operation.
• Confirm the agitation and drain states cannot be commanded concurrently by the program.
• Test stop behavior and any identified interlocks without defeating protective functions.
• Record remaining faults, corrective changes, and retest results. Do not return the washer to normal use while a control action or protective function remains unverified.

FAQ: Retrofit a washer with a CLICK PLC

Stop if circuit voltage, motor switching, or protective interlock function remains uncertain; contact the washer manufacturer’s authorized service channel or a qualified appliance/electrical technician before energizing the retrofit. For questions about CLICK PLC or C-more configuration, use AutomationDirect’s official support channel.