OMRON CP1W-8ER Pure Output Expansion Module

CP1W: Expansion unit for CP1 series

8: 8 points

E: Expansion

R: Relay normally open (NO) output

Type: Pure output expansion module, no input points

Core Specifications

Number of output points: 8-point relay NO output

Rated current per channel: 2 A (resistive load)

Output voltage range: AC/DC 4.5～30 V (passive relay contact)

On/off delay: approx. 15 ms

Power consumption: 5 V DC 0.21 A; 24 V DC 0.13 A

Dimensions: W66 × H90 × D50 mm

Weight: approx. 250 g

Certifications: CE, UL, CSA

Lifecycle status: Active, not discontinued

Compatible CPU Units

CP1E / CP1H / CP1L (CP1 series PLC); also compatible with legacy CPM1A/CPM2A

Note: 20-point CP1E CPU does not support expansion. Only 30/40/60-point CPUs can connect CP1W expansion units.

Cross-model Comparison (for selection)

CP1W-8ER: 8-point relay output (passive, AC/DC universal)

CP1W-8ET: 8-point NPN transistor output (DC24V only)

CP1W-8ED: 8-point DC24V input module

CP1W-16ER: 16-point relay output

Wiring Guidelines

1. Two independent common terminals: COM0 (00~03), COM1 (04~07)
2. Relay is dry contact: connect AC L / DC+ to COM as required, then wire the load to the contact terminal
3. Do not drive high-power motors directly; add intermediate contactors
4. For inductive loads (solenoid valves, coils), install freewheeling diodes (DC) or RC snubbers (AC) to extend relay life.

Troubleshooting

No output action:

1) Check if the expansion cable is firmly plugged in and the CPU recognizes the expansion unit

2) Verify the I/O address assignment (expansion I/O follows the previous unit’s address sequentially)

3) Measure COM power supply and check for open circuits in the load loop

Permanent ON for one channel: relay contact welding; replace the point or the whole module

No output on all channels: expansion function disabled, too many expansion units, or damaged cable.

Replacement Options

1. Direct replacement: CP1W-8ER (preferred, no program modification needed)
2. Transistor alternative: CP1W-8ET (for high-frequency switching and DC loads; cannot handle AC)
3. Domestic alternative: CP1-bus compatible 8-point relay expansion module (verify bus protocol and address mapping)

Service Life of CP1W-8ER (Limited by relay contacts)

Official rated life per relay channel

1. Mechanical life (no-load operation): ≥20 million operations
2. Electrical life (2 A resistive load): ≥100,000 operations

Key point: Electrical life is the bottleneck, not the PCB. Inductive loads (solenoid valves, contactor coils) drastically shorten service life down to 20,000～50,000 cycles. Snubber circuits will improve this.

Time Estimation (for project evaluation)

1 operation per minute: 100,000 cycles ≈ 19 years

1 operation per 10 seconds: 100,000 cycles ≈ 2.8 years

1 operation per second: 100,000 cycles ≈ 27 hours

For equipment with continuous ON state and rare switching: contact wear is minimal. In clean, temperature-controlled cabinets, the PCB, cable and terminals can run stably for 8～15 years. Service life is halved in high-temperature, humid and dusty environments.

Two Types of Service Life

Contact life: limited by switching cycles; failure symptoms: contact welding or poor contact

Module body life: PCB, cable and drive circuit; aging depends on environmental conditions, no fixed cycle rating.

Life Extension Tips

1. Add freewheeling diodes (DC) or RC snubbers (AC) for inductive loads such as solenoid valves and contactors.
2. Keep load current below 1 A; avoid continuous full-load (2 A) operation.
3. For high-frequency switching (cycles within seconds), use CP1W-8ET transistor output instead of ER relay modules.
4. Regularly inspect expansion cables and terminals for oxidation and loose connections.

Full List of OMRON CP1W Expansion Units (CP1E / CP1H / CP1L Compatible)

Note: CP1W units are bus-connected expansion modules (daisy-chained with flat cable). CIF, ADB and DAB boards are CPU side option boards (not bus expansion units). 20-point CP1E cannot use expansion units; only 30/40/60-point CP1E, CP1H and CP1L-M support CP1W expansion.

1. Digital Input Only Units

2. Digital Output Only Units (CP1W-8ER listed here)

3. Mixed I/O Units (Input + Output integrated)

4. Analog I/O Units (Voltage / Current signal)

5. Temperature Input Units (Thermocouple / Pt RTD)

6. Accessories (Expansion Cable)

Supplementary: CPU Side Option Boards (NOT Bus Expansion Units)

These plug directly into the CPU side slot and cannot be daisy-chained on the I/O bus:

CP1W-CIF01: RS232C

CP1W-CIF11: Non-isolated RS422/485

CP1W-CIF12 / CIF12-V1: Opto-isolated RS422/485

CP1W-CIF41: Ethernet option board

CP1W-DAM01: LCD display panel

CP1W-ADB21 / DAB21V / MAB221: Small analog option boards

Quick Selection Guide

1. High-frequency switching, solenoid valves, servo pulse output → Choose ET / ET1 transistor models, do not use ER relay modules
2. AC220V loads with infrequent switching → Select ER relay models
3. Thermocouple temperature measurement: TS001; Pt RTD: TS002; multi-point temperature monitoring: TS004
4. Analog I/O: MAD42 (4-in 2-out) is preferred; new projects select high-resolution AD042 / DA042