OMRON CPM1A Modules CPM1A-40CDR-A

Technical Dossier

Product Details And Specifications

OMRON CPM1A Series Technical Notes

The OMRON CPM1A series is a compact, fixed-I/O programmable logic controller platform deployed extensively across global heavy industry — including petrochemical plants, pharmaceutical manufacturing lines, water treatment facilities, and power generation auxiliaries. With a production lifecycle spanning from the mid-1990s through the 2000s, CPM1A units accumulated a massive installed base across Asia-Pacific, Europe, and the Americas. Their relay and transistor output variants remain embedded in legacy control architectures that are not scheduled for replacement, making long-term spare parts availability a critical operational concern for plant engineers and maintenance managers worldwide.

The Evolution of CPM1A Architecture

The CPM1A was introduced as a successor to OMRON's CPM1 platform, inheriting the same SYSMAC instruction set while expanding I/O density and peripheral connectivity. The core CPU integrates a built-in RS-232C port (on select models) and supports peripheral bus communication via the CPM1A's dedicated expansion I/O units. Clock speeds and memory capacities were fixed per model — the 10-point units offered 2,048 words of data memory, while the 40-point units extended this to support more complex ladder logic programs.

Architecturally, the CPM1A operates on a single-bus backplane-free design: expansion units connect directly to the CPU unit via a proprietary side-bus connector, eliminating the need for a rack. This design reduced panel footprint but imposed a hard limit of three expansion units per CPU. Communication options included the Host Link (SYSMAC WAY) protocol over RS-232C, enabling integration with OMRON's SCADA and HMI platforms of the era, including the NT-series operator terminals.

As the platform matured, OMRON introduced the CPM2A and subsequently the CP1E/CP1L/CP1H families as functional replacements. The CP1E series is the current recommended migration path for CPM1A applications, offering backward-compatible instruction sets and modern Ethernet/USB connectivity. However, direct hardware substitution is not possible without I/O rewiring and program conversion, meaning the CPM1A remains in active service at sites where migration costs are prohibitive.

CPM1A Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly sourced models within the OMRON CPM1A series, classified by I/O count and output type:

CPU Units — Relay Output

• CPM1A-10CDR-A: 10-pt CPU unit, 6 DC inputs, 4 relay outputs, 100–240 VAC power supply.
• CPM1A-20CDR-A: 20-pt CPU unit, 12 DC inputs, 8 relay outputs, 100–240 VAC power supply.
• CPM1A-30CDR-A: 30-pt CPU unit, 18 DC inputs, 12 relay outputs, 100–240 VAC power supply.
• CPM1A-40CDR-A: 40-pt CPU unit, 24 DC inputs, 16 relay outputs, 100–240 VAC power supply. Standard industrial workhorse for mid-complexity relay control.
• CPM1A-10CDR-D: 10-pt CPU unit, 6 DC inputs, 4 relay outputs, 24 VDC power supply.
• CPM1A-20CDR-D: 20-pt CPU unit, 12 DC inputs, 8 relay outputs, 24 VDC power supply.
• CPM1A-30CDR-D: 30-pt CPU unit, 18 DC inputs, 12 relay outputs, 24 VDC power supply.
• CPM1A-40CDR-D: 40-pt CPU unit, 24 DC inputs, 16 relay outputs, 24 VDC power supply.

CPU Units — Transistor Output (Sinking / NPN)

• CPM1A-10CDT-D: 10-pt CPU unit, 6 DC inputs, 4 transistor sinking outputs, 24 VDC supply.
• CPM1A-20CDT-D: 20-pt CPU unit, 12 DC inputs, 8 transistor sinking outputs, 24 VDC supply.
• CPM1A-30CDT-D: 30-pt CPU unit, 18 DC inputs, 12 transistor sinking outputs, 24 VDC supply.
• CPM1A-40CDT-D: 40-pt CPU unit, 24 DC inputs, 16 transistor sinking outputs, 24 VDC supply. Preferred for high-speed pulse output and servo positioning applications.

CPU Units — Transistor Output (Sourcing / PNP)

• CPM1A-10CDT1-D: 10-pt CPU unit, 6 DC inputs, 4 transistor sourcing outputs, 24 VDC supply.
• CPM1A-20CDT1-D: 20-pt CPU unit, 12 DC inputs, 8 transistor sourcing outputs, 24 VDC supply.
• CPM1A-40CDT1-D: 40-pt CPU unit, 24 DC inputs, 16 transistor sourcing outputs, 24 VDC supply.

Expansion I/O Units

• CPM1A-8ED: 8-pt expansion DI unit, 8 DC inputs, no outputs. Extends input capacity of any CPM1A CPU.
• CPM1A-8ER: 8-pt expansion DO unit, 8 relay outputs. Adds discrete relay output channels.
• CPM1A-8ET: 8-pt expansion DO unit, 8 transistor sinking outputs.
• CPM1A-20EDR: 20-pt expansion mixed I/O unit, 12 DC inputs, 8 relay outputs.
• CPM1A-20EDT: 20-pt expansion mixed I/O unit, 12 DC inputs, 8 transistor sinking outputs.

Analog I/O Units

• CPM1A-MAD01: Analog I/O unit, 2 analog inputs (0–10 V / 4–20 mA), 1 analog output. Enables closed-loop process control on CPM1A platforms.
• CPM1A-MAD11: Analog I/O unit, 2 analog inputs, 1 analog output with extended resolution. Used in temperature and pressure regulation loops.

Communication & Special Function Units

• CPM1A-CIF01: RS-232C adapter unit for peripheral port communication with host computers and HMI panels.
• CPM1A-CIF11: RS-422A/485 adapter unit for multi-drop network configurations up to 32 nodes.

Quality Control for the CPM1A Range

Each CPM1A unit processed by DriveKNMS undergoes a structured inspection and functional verification protocol before dispatch:

• Visual inspection: PCB examination for corrosion, capacitor bulge, relay contact wear, and connector pin integrity. The CPM1A's side-bus expansion connector is a known wear point and is inspected under magnification.
• Power-on test: Unit is powered at rated voltage (100–240 VAC or 24 VDC per model). RUN/ALARM LED status is verified. Abnormal current draw is flagged.
• I/O functional test: All discrete input channels are stimulated individually. All relay and transistor output channels are activated under resistive load and verified with a calibrated meter. Relay contact resistance is measured; contacts exceeding 100 mΩ are flagged for replacement.
• Communication port test: RS-232C peripheral port is tested using OMRON CX-Programmer or equivalent terminal software. Baud rate, parity, and data frame integrity are confirmed.
• Memory retention test: Internal capacitor-backed RAM is verified for data retention over a minimum 72-hour unpowered period. Units failing retention are reconditioned or rejected.
• Analog I/O calibration (for MAD-series units): Input and output channels are calibrated against a traceable reference standard. Linearity error must be within ±0.5% of full scale.