OMRON CQM1-PA203 PLC Power Supply Unit

Nome completo del prodotto: OMRON SYSMAC CQM1 Series PLC AC Unità di alimentazione

Stato: Interrotto (Marzo 2019). No genuine new stock available from manufacturer, and no official direct replacement model. Supplies on the market are mainly used dismantled units and refurbished parts.

Ospite compatibile: CQM1 / CQM1H series compact modular PLC. Montaggio su guida DIN, installed at the far left of the rack to supply power to processore and I/O modules.

1. Specifiche elettriche principali

Comparison with power supplies in the same series

CQM1-PA203: 5V@3.6A, low capacity, no 24V DC output

CQM1-PA206: 5V@6A, with 0.5A 24VDC auxiliary output

CQM1-PA216: Higher power AC power supply

CQM1-PD026: DC input power supply unit

2. Definizione del codice modello

CQM1: Codice della serie (SYSMAC CQM1 compact PLC)

PA: Power AC, AC input power supply unit

203: Specification revision code, denotes wide-range AC input with 5V 3.6A power rating

3. System Selection Guidelines
4. Total 5V current consumption of all modules (processore + I/O + special modules) must be ≤3.6A. Excessive load will cause frequent power dropout and power supply damage. Sum the 5V power consumption of each unit during selection.
5. Modules are powered via backplane bus. External 5V cannot feed the backplane. Power can only be supplied by this power unit.
6. No 24V sensor power terminals. Sensors on site require an independent external 24V power supply.
7. Risoluzione dei problemi (Key Points for Used Units)

The most common failure mode of CQM1-PA203 is aging and bulging of internal electrolytic capacitors, a typical defect for this legacy power supply.

Sintomi: POWER LED does not light up after power-on; LED flashes or restarts repeatedly seconds after energization; voltage drops under load while voltage is normal at no load, power fails once CPU is fitted.

Ispezione: Disconnect all CPU/I/O modules, power up independently and measure backplane 5V output. If 5V is normal at no load but voltage collapses under load, capacitor aging is highly likely.

Acceptance checklist for second-hand units: Inspect PCB for swollen capacitors, burn marks and terminal corrosion; perform full-load aging test.

5. Opzioni di sostituzione (System Retrofit)

No pin-compatible new unit from OEM. Two available solutions:

1. Refurbishment / Second-hand Replacement: Retain existing CQM1 platform. Purchase used CQM1-PA203, replace capacitors and run load test. Suitable for short-term equipment life extension.
2. Full Machine Upgrade: Migrate the entire PLC system to CJ2M series (CJ2M-CPU + CJ2M power supply). Program migration is required; racks and all modules need replacement. This is a project-level modification for long-term stable operation.
3. Scenari applicativi

Legacy machine tools, macchine per l'imballaggio, textile equipment and old production lines equipped with OMRON CQM1/CQM1H compact PLC.

CQM1 → CJ2M Full System Migration: Elenco dell'hardware & Program Migration Checklist

Reference OMRON official manual P087-E1-03 (CQM1(H) to CJ2M)

Premessa fondamentale: CQM1 rack, backplane and power supply (CQM1-PA203) must be discarded and cannot be reused. CJ2M adopts CJ series backplane-less snap-together module architecture.

1. Hardware Selection List (By Module Category)

1.1 Selezione della CPU (Match Original CQM1 Program Capacity & Punti di I/O)

Salvato: CJ1W-BAT01 battery (for D/HR memory retention); end plate CJ1W-TER01 (must be installed at the rightmost of rack, otherwise error occurs)

1.2 CJ Series Power Supply (Replaces CQM1-PA203)

CJ1W-PA202: CA 100-240 V, 5V 5A (più comunemente usato)

CJ1W-PA205R: Wide AC input, 5V 10A for high-power systems

Mounting sequence: Power supply → CPU → I/O / Special modules → End plate

1.3 I/O Module Replacement (CQM1 Modules Cannot Plug into CJ Rack)

Fast Wiring Option: CJ1W-AT4xx terminal adapter. Mount original CQM1 terminal block directly onto CJ1W I/O modules, no need to re-crimp field cables. Svantaggio: increased module depth; reserve space inside DIN cabinet.

1.4 Moduli speciali / Bus Module Replacement (Critical Pitfalls)

1. Analog modules (CQM1-MAD01/MAD02 etc.) → CJ1W-MAD42, CJ1W-DA041; Unit number needs re-dip switch setting, CIO channel addresses will change.
2. CQM1-B7A Remote I/O: B7A protocol not compatible with CJ2M. Master station and all remote slaves must be replaced with CompoNet (CJ1W-CRM21). All remote cables need rework; heavy workload.
3. Moduli di comunicazione: CQM1-SCB41 → CJ1W-SCU21-V1 serial module; DeviceNet CQM1-DRM21 → CJ1W-DRM21.

1.5 Cremagliera & DIN Rail Accessories

CJ series uses no backplane; modules snap together directly.

Massimo 10 units for single CPU rack; expansion racks use CJ1W-IC101 (CPU rack side) + CJ1W-II101 (expansion side). Fino a 3 rack di espansione.

1.6 Hardware Test Tool List

Programmatore CX (V9.5+ recommended), Cavo di programmazione USB (CJ2M with built-in USB port)

Multimetro, 24Alimentazione V, terminal jumpers, stampante per etichette

PC with backup of original program

2. Program Migration Checklist (CX-Programmer Migration Workflow)

Core note: CX-P can auto-convert most ladder logic, but address mapping, some instructions and flags may fail. Converted project cannot be downloaded directly for production.

✅ Phase 1: Pre-migration Preparation (Before Shutdown)

1. Upload complete CQM1 program, I/O comments, initial values of D/HR memory and PLC system settings online; keep two separate backups.
2. Record original system information:

Slot position of each module, unit number (DIP switch settings of special modules)

CIO channel assignment (ingresso, produzione, channels allocated to special modules)

Parametri di comunicazione: seriale / DeviceNet baud rate, station number

Interrupt program, high-speed counter, pulse output parameters

Current values of D, risorse umane, AR, TIM/CNT in original PLC

3. List special instructions, PID, high-speed counter and interrupt instructions used in original program.
4. Export I/O address table and create old-to-new address comparison sheet (most critical document).

✅ Phase 2: CX-P Model Conversion Procedure

1. Open CQM1 project in CX-P → PLC → Change Model, select corresponding CJ2M CPU model.
2. Software auto-converts instructions; check conversion errors and warnings in output window.
3. Chiave: Memory Map Correction (CQM1 vs CJ2M Memory Differences)

CQM1: Fixed CIO allocation; CJ2M: Basic I/O units auto assigned CIO 0000~0159CH; Special I/O units: 2000~2959CH, 10CH per unit; CPU bus units 1500~1899CH, 25CH per unit. Allocation rules differ.

Manually reassign CIO to match original CQM1 channel mapping, otherwise all I/O will be misaligned.

AR area (auxiliary relay) address definitions differ. AR flags are a frequent source of faults.

4. Item-by-item instruction verification (failed conversion or behaviour-changed instructions)

Operation operands of some BCD/BIN conversion instructions are changed;

Interrupt instructions: Legacy CQM1 interrupt instructions must be rewritten in CJ2M using MSKS / MSKR / CLI / EI / DI;

PID instruction parameter structure differs;

Carry and zero flags (P_Flag) behave differently after execution of certain instructions, causing hidden logic faults without compile errors.

5. Data memory migration:

After model conversion, D and HR values are not inherited automatically. Manually copy initial values between CQM1 memory window and CJ2M memory window. Verify preset values of TIM/CNT.

6. PLC System Settings:

Cycle time, interrupt response, serial parameters, battery detection, power-up mode;

CJ2M system setting pages are completely different from CQM1; old settings cannot be reused.

✅ Phase 3: Compilazione, Simulation & Offline Debugging

1. Full compilation, clear all Errors; Evaluate all Warnings one by one, do not ignore.
2. Offline simulation: Force I/O status to test logic branches, timer, counters and alarm logic.
3. Verificare: Old/new I/O address table, special module channels, communication addresses.
4. Document update: Update program comments, electrical drawings and I/O table.

✅ Phase 4: Hardware Power-up & Online Debugging (Step-by-Step Safe Procedure)

1. Power off and assemble full CJ2M hardware. Verify module order, DIP switch settings and end plate installation.
2. No-load power-up (disconnect field actuator outputs):

Check power supply and CPU RUN LED; confirm no I/O or unit errors;

Download program + PLC settings + D area initial values;

Force input points and check CIO input status; force outputs and measure terminals.

3. Power on with sensors: Verify all DI input signals.
4. Single-point test of DO outputs without load.
5. Single-point test of special modules: analogico, high-speed counter, uscita ad impulsi.
6. Prova di comunicazione: porta seriale, bus and HMI/host computer communication.
7. Full machine no-load sequence test, monitor scan cycle time.

⚠️ CJ2M executes instructions faster, scan cycle is shorter, which may trigger timing-dependent issues on original CQM1 logic (per esempio. latch and delay logic). Timing validation is required; add software delay if necessary.

✅ Phase 5: Load Trial Run & Acceptance

1. Loaded jogging and single-cycle operation;
2. Continuous trial run, monitor alarms, memory and CPU error logs;
3. Back up final CJ2M program and memory image; update equipment files;
4. Prepare rollback plan (retain original CQM1 system as emergency backup).
5. Migration Risk Checklist (Critical Pitfalls)
6. ❗ Different CIO allocation mechanism: I/O address misalignment even if compilation passes, leading to unintended machine movement.
7. ❗ Behaviour difference of flags (P_On, P_Off, P_CY, P_EQ), hidden logic bugs hard to detect via simulation.
8. ❗ CQM1-B7A remote I/O cannot be reused; è necessaria la sostituzione completa.
9. ❗ Shorter scan cycle introduces timing issues; many legacy logics rely on slower scan speed of old PLC.
10. ❗ Memory loss on battery replacement for CJ2M: D area data will be lost when replacing battery with power off. Complete data backup is mandatory.
11. ❗ Space interference with CJ1W-AT4xx adapter; CPU USB port may be blocked. Verify cabinet depth in advance.
12. Deliverable List After Migration Completion
13. Full CJ2M CX-P project (with comments and I/O table)
14. Old-to-new I/O address comparison sheet
15. D/HR memory initial value backup file
16. Updated hardware wiring diagram with CJ module terminals
17. Module DIP switch table and communication parameter document
18. Test log and trial run report
19. Troubleshooting manual
20. Comparison of Optional Simplified Solutions

Opzione A (Full migration to CJ2M): Long-term stable solution. Costo più elevato, longer downtime and heavy program modification.

Opzione B (Only repair CQM1-PA203 power supply, keep original PLC system): Low cost for rapid life extension. However CPU and other modules remain aged, only suitable for short-term transition.