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Part of the Omron CJ-Series PLCs series — see the full model table, lifecycle status and replacement parts.

Omron CJ1W-PRM21 — front face of the CJ1W-PRM21 module on a wooden surface showing the green PRM21 LED indicator at top / black RUN ERC PRM COMM ERH BST BF LED array / UNIT No. 0-9 / A-F rotary selector / D-Sub 9-pin PROFIBUS BUS connector on the lower housing with the BUS label to its right

Omron CJ1W-PRM21 — CJ PROFIBUS DP Master Unit

SKU: CJ1W-PRM21

USD 486.00

CJ-series PROFIBUS-DP master unit with DP-V1 support, CX-PROFIBUS configurator, baud rates to 12 Mbit/s, up to 125 slaves. 0.40 A at 5 VDC.

1-Year Warranty Full manufacturer warranty
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Product Overview

The Omron CJ1W-PRM21 is the CJ-series PROFIBUS-DP master unit. It is 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.

Max 7,168 words of I/O across the network 244 bytes in / 244 bytes out per PROFIBUS slave 400 mA at 5 VDC from CJ backplane, 31 x 90 x 65 mm slim body at 100 g Max 7,168 words of I/O across the network

Compatible controllers and sibling SKUs are listed in the related products row below.

Key Features

  • 400 mA at 5 VDC from CJ backplane, 31 x 90 x 65 mm slim body at 100 g
  • Max 7,168 words of I/O across the network
  • PROFIBUS-DP master class 1 with DP-V1 acyclic data types supported
  • 244 bytes in / 244 bytes out per PROFIBUS slave
  • SKU: CJ1W-PRM21
  • Series: CJ-series CPU-bus Special I/O / high-function unit
  • I/O: 7 I/O

Best-Fit Applications

  • Replacing an older CS1W-PRM21 on a CS-series rack with the slim CJ1W-PRM21 on a CJ-series rack
  • DP-V1 acyclic parameter read / write for VFD commissioning and diagnostics
  • Reading / writing third-party PROFIBUS-DP slaves (VFDs, valves, weigh scales, encoder blocks) via GSD file import

Buying Checklist

  • Pick the CJ1W-DRM21 for a DeviceNet master when PROFIBUS-DP is not in scope
  • Pick the CS1W-PRM21 instead for a CS-series CPU bus unit (same functionality, CS1 / CS1D rack)
  • Pick the CJ1W-ETN21 / CJ1W-EIP21 for Ethernet / EtherNet/IP upstream networks (the PRM21 covers the PROFIBUS-DP side only)

Technical Specifications

Series CJ-series CPU-bus Special I/O / high-function unit
Model CJ1W-PRM21
Function PROFIBUS-DP master class 1 + DP-V1 acyclic data types
Bus Connector 1 x D-Sub 9-pin PROFIBUS-DP connector on front face (BUS)
Baud Rates 9.6 k / 19.2 k / 45.45 k / 93.75 k / 187.5 k / 500 k / 1.5 M / 3 M / 6 M / 12 Mbit/s per EN50170 Vol. 2 / IEC 61158
PROFIBUS Address 0-125 per master / slave, set via CX-PROFIBUS
Slaves per Bus Up to 125 PROFIBUS slaves
I/O Capacity 7,168 words total / 244 bytes in + 244 bytes out per slave
Control / Status Area 25 words in the CJ CPU memory area
Current Draw 0.40 A at 5 VDC from CJ backplane
Per-rack Limit Up to 16 PRM21 units per CJ PLC (depends on CPU type)
Dimensions / Weight / Origin 31 x 90 x 65 mm slim body, 100 g, MADE IN THE NETHERLANDS by Omron Manufacturing B.V.; 0 to +50 °C operating

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-PRM21

Is the CJ1W-PRM21 a protocol macro module?
No. The PRM21 is a PROFIBUS-DP master unit. The protocol macro feature lives on the CJ1W-SCU21-V1 / SCU31-V1 (and the SCU@2 high-speed SCU22 / SCU32 / SCU42) serial communication units. The PRM21 is a dedicated PROFIBUS-DP master class 1 with DP-V1 acyclic data types -- the actual nameplate on the unit reads 'PROFIBUS DP-V1 Master Unit'.
How many PROFIBUS slaves can the CJ1W-PRM21 handle?
Up to 125 PROFIBUS-DP slaves per bus at 244 bytes in + 244 bytes out per slave, for 7,168 words of total I/O across the network. Up to 16 PRM21 units can sit on one CJ PLC (final count depends on the CJ CPU type), so multi-master PROFIBUS-DP sub-networks from a single CJ rack are supported.
What software configures the CJ1W-PRM21?
CX-PROFIBUS, an FTD/DTM-based configurator under CX-One. The master is set up in CX-PROFIBUS and any third-party slave is imported via its GSD file and configured through the Generic DTM. CX-Programmer alone is not enough for the PROFIBUS-DP master and slave configuration.
Does the CJ1W-PRM21 support DP-V1 acyclic services?
Yes. The PRM21 lists 'Basic PROFIBUS-DP master Class 1 functions plus DP-V1 data types support' on the Omron specification page, so acyclic parameter read / write and alarm handling are supported.

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