Part of the Omron CJ-Series PLCs series — see the full model table, lifecycle status and replacement parts.
Omron CJ1W-II101 — I/O Interface Unit, CJ Expansion Rack
SKU: CJ1W-II101USD 49.00
CJ-series I/O Interface Unit for expansion rack; pairs with CJ1W-IC101 via CS1W-CN@@3 cable
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Product Overview
The Omron CJ1W-II101 is the I/O Interface Unit that terminates the I/O expansion bus on each CJ-series expansion rack. manufactured by Omron Corporation. Hengyixin Automation stocks this controller in Xiamen and ships within 3-5 business days to most Asian, European, and North American ports.
One CJ1W-II101 is required per expansion rack — it mounts immediately to the right of the expansion rack's power supply unit and converts the daisy-chained CS1W-CN@@3 cable signal from the CPU rack's CJ1W-IC101 into the local expansion rack's I/O backplane bus. Without the II101 on the expansion rack, the rack's power supply will power up (the green PWR LED will be lit) but the CPU will not be able to see any of the I/O modules mounted on that rack.
Conversely, if you are keeping a CS1 CPU and want to add modern CJ1W I/O, you must use the CS1W-II101 (not the CJ1W-II101) on the expansion racks.
Key Features
- 5 VDC backplane current consumption 0.02 A
- Standard 31 mm wide CJ1W module form factor
- One CJ1W-II101 required per expansion rack
- Connects to CJ1W-IC101 or previous II101 via CS1W-CN@@3 cable
- SKU: CJ1W-II101
- Series: CJ-series I/O Control / Interface
Best-Fit Applications
- Migration of an existing CS1W expansion rack design to a CJ2M-CPU33 — replace the CS1W-II101 with CJ1W-II101
- Expansion rack 1 of a CJ2M-CPU33 system with CJ1W-ID211 inputs and CJ1W-OC211 outputs — II101 on the expansion rack side.
- Long-distance expansion up to 10 m between adjacent racks using CS1W-CN133 cables — for large-machine layouts where racks are physically separated
Buying Checklist
- Pick CS1W-CN713 for 0.7 m cable
- Pick CS1W-CN313 for 0.3 m cable
- Pick CS1W-CN133 for 10 m cable
Technical Specifications
| Model | CJ1W-II101 |
|---|---|
| Series | CJ-series I/O Control / Interface |
| Type | I/O Interface Unit for expansion rack |
| Mounting Position | Immediately to the right of the expansion rack PSU (mandatory) |
| Number per System | 1 per expansion rack (max 3 per CJ CPU) |
| Connected Unit | CJ1W-IC101 (rack 1) or previous CJ1W-II101 (racks 2 and 3) |
| Maximum Expansion Racks | 3 (CJ1M / CJ2M / CJ2H / NJ series); 2 (CJ1G-CPU42H/43H legacy) |
| Total Cable Length Limit | 12 m maximum across all racks |
| Connector Type | 40-pin high-density connector on front face |
| Current Consumption (5 V) | 0.02 A |
| Current Consumption (24 V) | 0 A (no 24 V consumption) |
| Operating Temperature | 0 to +55 °C |
| Storage Temperature | -20 to +75 °C |
| Certifications | UL (UC1), CSA (N), Lloyd's (L), CE |
Manufacturer documentation
Omron's own product page, where the manufacturer's current specification and lifecycle information are published. We are an independent distributor and cannot mirror those documents; the link goes to Omron's site.
FAQ for CJ1W-II101
Does every CJ expansion rack need a CJ1W-II101?
Yes — exactly one CJ1W-II101 is required per expansion rack. The II101 is the bus-termination module that converts the daisy-chained CS1W-CN@@3 cable signal from the CPU rack into the local I/O backplane bus.
Can I use a CS1W-II101 instead of a CJ1W-II101?
No — the CS1W-II101 and CJ1W-II101 are physically and electrically different. The CS1W-II101 has a different front-panel connector pinout and firmware revision than the CJ1W-II101. Plugging a CS1W-II101 into a CJ1 / CJ2 / NJ CPU system will not work (the CPU will not recognise it, or it may damage the bus). Plugging a CJ1W-II101 into a CS1 CPU system will also not work.
What's the maximum number of expansion racks per CJ CPU?
3 expansion racks maximum for the CJ1M, CJ2M, CJ2H, and NJ-series CPUs (with the NJ101 / NJ301 / NJ501 family). So you need 1, 2, or 3 CJ1W-II101 modules depending on how many expansion racks you use. The older CJ1G-CPU42H and CJ1G-CPU43H support only 2 expansion racks (so up to 2 II101 modules). The CS1G-CPU43H / CS1G-CPU42H / CS1G-CPU44H / CS1G-CPU45H also support 3 expansion racks (using CS1W-II101).
What happens if I mount something between the PSU and the II101?
The I/O expansion bus will not propagate, and the CPU will not see any I/O modules on that expansion rack. The CJ1W-II101 has the same strict mounting rule as the CJ1W-IC101: it MUST be the first module to the right of the expansion rack's power supply. If you have a CJ1W-ID211 input module or any other CJ1W module between the PSU and the II101, the bus signal will be blocked and the CPU will report an I/O verification error.
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