OMRON CPM1A Modules

Technical Dossier

Product Details And Specifications

OMRON CPM1A Series: Comprehensive Module Range and Technical Overview

The OMRON CPM1A series is a compact, fixed-I/O programmable logic controller platform deployed across global heavy industry sectors including petrochemical processing, refinery automation, water treatment, and discrete manufacturing. Introduced as a successor to the CPM1 line, the CPM1A established itself as a cost-effective yet reliable control node in distributed machine-level automation architectures. Its installed base spans facilities in Asia-Pacific, the Middle East, and Europe, where long equipment lifecycles make continued access to spare modules a critical operational requirement.

The CPM1A operates on OMRON's proprietary SYSMAC instruction set and communicates via RS-232C and peripheral ports, supporting host link (SYSMAC WAY) and NT Link protocols. CPU units support ladder diagram programming through CX-Programmer software. The series is fully compatible with OMRON's C-series expansion I/O architecture, allowing modular expansion up to 100 I/O points depending on the CPU variant.

The Evolution of CPM1A Architecture

The CPM1A was introduced in the mid-1990s as a compact successor to the CPM1, incorporating onboard analog capability options and expanded memory. It belongs to OMRON's C-series PLC family, which also includes the CPM2A, CPM2C, CQM1, and CJ1M lines. The CPM1A CPU units range from 10 to 40 I/O points in the base unit, with relay and transistor output variants to suit different load types.

As automation architectures evolved toward open-network fieldbus systems (DeviceNet, EtherNet/IP), the CPM1A's RS-232C-centric communication model became a compatibility constraint in modern integration projects. OMRON officially positioned the CJ2M and CP1E series as functional replacements. However, the CPM1A remains in active service in legacy installations where full system replacement is not economically viable. Compatibility with existing ladder programs and I/O wiring layouts makes module-level replacement the preferred maintenance strategy for these sites.

CPM1A Full Catalog & Functionalities (SKU List)

CPU Units (Relay Output)

• CPM1A-10CDR-A: 10-point CPU, 6 DC inputs, 4 relay outputs, AC power supply.
• CPM1A-20CDR-A: 20-point CPU, 12 DC inputs, 8 relay outputs, AC power supply.
• CPM1A-20CDR-A-V1: 20-point CPU, revised V1 hardware, 12 DC inputs, 8 relay outputs, AC power, enhanced noise immunity.
• CPM1A-30CDR-A: 30-point CPU, 18 DC inputs, 12 relay outputs, AC power supply.
• CPM1A-40CDR-A: 40-point CPU, 24 DC inputs, 16 relay outputs, AC power supply.

CPU Units (Transistor Output — NPN Sinking)

• CPM1A-10CDT-D: 10-point CPU, 6 DC inputs, 4 NPN transistor outputs, DC power supply.
• CPM1A-20CDT-D: 20-point CPU, 12 DC inputs, 8 NPN transistor outputs, DC power supply.
• CPM1A-30CDT-D: 30-point CPU, 18 DC inputs, 12 NPN transistor outputs, DC power supply.
• CPM1A-40CDT-D: 40-point CPU, 24 DC inputs, 16 NPN transistor outputs, DC power supply.

CPU Units (Transistor Output — PNP Sourcing)

• CPM1A-20CDT1-D: 20-point CPU, 12 DC inputs, 8 PNP transistor outputs, DC power supply.
• CPM1A-30CDT1-D: 30-point CPU, 18 DC inputs, 12 PNP transistor outputs, DC power supply.
• CPM1A-40CDT1-D: 40-point CPU, 24 DC inputs, 16 PNP transistor outputs, DC power supply.

Expansion I/O Units

• CPM1A-8ED: 8-point expansion digital input unit, 24 VDC.
• CPM1A-8ER: 8-point expansion relay output unit.
• CPM1A-8ET: 8-point expansion NPN transistor output unit.
• CPM1A-20EDR: 20-point expansion I/O unit, 12 inputs / 8 relay outputs.

Analog I/O Expansion Units

• CPM1A-MAD01: 2 analog inputs (0–10 V / 4–20 mA), 1 analog output, 12-bit resolution.
• CPM1A-MAD11: 2 analog inputs, 1 analog output, high-resolution variant.

Communication & Specialty Units

• CPM1A-CIF01: RS-232C adapter for host link / NT Link communication.
• CPM1A-CIF11: RS-422A/485 adapter for multi-drop host link networks.

Sourcing Hard-to-Find & Obsolete CPM1A Parts

The CPM1A series has reached end-of-production status with OMRON. Standard distribution channels no longer carry new stock for the majority of CPU and expansion units. For facilities operating CPM1A-based control systems, the practical options are: (1) sourcing tested surplus units from specialist distributors, (2) refurbished exchange programs, or (3) full migration to a supported platform such as the OMRON CP1E or CJ2M.

DriveKNMS maintains a dedicated inventory of CPM1A modules sourced from decommissioned equipment, factory overstock, and controlled surplus channels. All units are catalogued by hardware revision (e.g., V1 suffix on CPM1A-20CDR-A-V1 denotes a revised PCB with improved EMC performance). Customers requiring long-term maintenance contracts for CPM1A-equipped machinery can contact DriveKNMS for lifecycle extension support agreements, including multi-year supply commitments and cross-reference mapping to compatible replacement platforms.

Quality Control for the CPM1A Range

CPM1A modules undergo a structured inspection and functional test protocol prior to dispatch. Each CPU unit is powered and loaded with a diagnostic ladder program to verify: input response time, output switching integrity (relay contact resistance for CDR variants; transistor saturation voltage for CDT variants), memory read/write cycles, and peripheral port communication handshake. Expansion I/O units are tested in conjunction with a reference CPU to confirm backplane connector integrity and I/O mapping accuracy.

Relay output units (CDR variants) receive additional contact wear assessment. Units with relay contact resistance exceeding 100 mΩ are rejected. Analog expansion units (MAD01, MAD11) are calibrated against a traceable reference signal source to verify linearity and offset within published OMRON specifications. All tested units are issued a DriveKNMS inspection record with test date, technician ID, and pass/fail criteria documentation.

© 2026 DriveKNMS. All trademarks belong to their respective owners. Specifications are for reference only and subject to change without notice. Verify all parameters against official documentation before installation.