Omron C1000H/C2000H PLC Practical Guide

Omron C1000H/C2000H PLC Practical Guide

Product positioning and core features

Omron C1000H and C2000H are rack mounted PLCs designed for large-scale control systems in the 1980s and 1990s, widely used in fields such as factory automation, process control, and infrastructure. The C1000H supports a maximum of 1024 I/O points (expandable to 2048 points when using remote I/O), while the C2000H is based on 2048 point I/O. The most unique feature of C2000H is the Duplex dual machine redundancy system, which allows two CPUs to be installed on the same rack, one as the active master and the other as a hot standby. When the main CPU fails, it automatically switches, greatly improving system availability.

This article is based on the installation guide manual for C1000H/C2000H. From an engineering perspective, it systematically explains hardware component identification, power selection and current budgeting, rack installation and expansion, I/O wiring specifications, Duplex system configuration, as well as daily maintenance and troubleshooting.

Detailed explanation of system components

2.1 Rack type and slot configuration

C1000H and C2000H adopt a modular rack structure, with different backboards used for different systems.

C1000H CPU rack: Provides multiple models including 3, 5, 6, 8, and 9 I/O slots. The rightmost slot is typically used for power units, while some of the rightmost slots on the backplane (depending on the model) are dedicated to link units (PC Link, Host Link, SYSMAC NET Link, etc.). Common backboards: 3G2A5-BC081 (8 I/O slots+3 link slots), C500-BC091 (9 I/O slots+6 link slots), etc.

C2000H Simplex (single CPU) system: The CPU rack only has 6 I/O slots (model 3G2C5-BC061), which is two fewer than C1000H, but can still connect up to 7 expansion I/O racks.

C2000H Duplex system: There are no I/O units installed on the CPU rack (3G2C5-BC001), but two CPU units and one Duplex unit are installed. All I/O units are installed on an additional I/O rack (3G2C5-BI082), which is connected to the CPU rack via two dedicated cables.

Expansion I/O Rack: Used for expanding I/O points, models include 3G2A5-BI081 (8 slots), 3G2A5-BI051 (5 slots), and the C2000H dedicated 3G2C5-BI083 (with online replacement function).

2.2 CPU Unit

The CPU models for C1000H and C2000H are C1000H-CPU01-EV1 and C2000H-CPU01-EV1, respectively. The CPU itself does not come with power and memory, and requires separate configuration of power and memory packs. The front panel of the CPU provides:

Peripheral connector: can be directly inserted into a programmer (such as 3G2A5-PRO13-E), can be installed directly without cables

Memory pack slot (right side)

Run/stop switch and status indicator light

2.3 Power Supply Unit

The power unit is installed on the far right side of the rack (or in a dedicated slot). The output capacity of different models varies greatly, and the current available for I/O units in different systems is also different. This is the most critical data in engineering selection.

Power supply model Input voltage 5V Output capacity Available I/O current (C1000H) Available I/O current (C2000H Simplex) 24V output

3G2A5-PS221-E AC 100-120/200-240V optional 7A 4A 3A 0.8A

3G2A5-PS223-E AC Same as 12A 9A 8A None

3G2A5-PS211-E 24V DC 7A 4A 3A None

C500-PS213-E 24V DC 9A 6A 5A None

The same model can have different I/O currents under different system architectures, as the Duplex system requires additional consumption of backplane bus current. For example, PS221-E can use 4A in C1000H, but only 3A in C2000H Simplex.

I/O rack power supply (for expansion racks or C2000H Duplex I/O racks):

3G2A5-PS222-E (AC): 7A output, 6.5A available, with 24V 0.8A output

3G2A5-PS212-E (24V DC): 7A output, 6.5A available, no 24V output

Important: When calculating the total 5V consumption of each rack, you cannot just look at the nominal output capacity of the power supply, you must use the "available I/O current" value. CPU, I/O control unit, I/O interface unit, etc. also consume current and need to be included together.

2.4 I/O Control Unit and I/O Interface Unit

I/O Control Unit (3G2A5-II101): Installed in the leftmost I/O slot of the CPU rack, used to connect to the expansion I/O rack. Even in the C2000H Duplex system, it is installed on the I/O rack instead of the CPU rack.

I/O interface unit (3G2A5-II002): One must be installed in the leftmost slot of each expansion I/O rack for communication with the previous level.

2.5 Duplex Unit (C2000H Duplex only)

The Duplex unit (model not separately provided in the manual, but as a system component) is installed between two CPUs and provides the following functions:

System switch: Set the system to DPL (dual machine) or SPL (single machine)

Active CPU selection switch: Select the right CPU or left CPU as the active CPU

CPU ON/OFF switch: Each CPU has an independent switch and must be placed in the ON position to operate in dual machine mode

Status indicator light: indicates active/standby status, errors, etc

When dual machines are working, the active CPU executes programs and controls I/O, while the standby CPU only executes programs but does not output. When a fatal error occurs in the active CPU, the standby CPU automatically takes over. The faulty CPU can be replaced without shutting down (provided that the system has correctly configured the I/O Remove Unit).