Configuring VIPA Profibus Remote I/O on Omron CJ1G

Project Constraints and Lead-Time Decision

When an Omron CJ1G-CPU45H application requires approximately 25 remote I/O slaves and the preferred DRT2-series DeviceNet units carry a 10-week lead time, the engineering decision collapses to a small set of constraints: available fieldbus master module, software toolchain, third-party slave availability, and Profibus DP vs. DeviceNet commissioning skill on the team. The CJ1G platform supports both protocols, but each path requires different hardware and configuration software.

The two fieldbus options on the CJ1G family for non-EtherNet/IP remote I/O are:

• DeviceNet via CJ1W-DRM21 master + DRT2 slaves or third-party EDS-based slaves (Phoenix Contact, Weidmüller, Beckhoff).
• Profibus-DP via CJ1W-PRM21 master + GSD-based slaves (VIPA, Phoenix Contact, Weidmüller, Siemens ET200).

For a 4-week machine build window, the deciding factor is the slave-delivery date, not the protocol complexity. Once a slave vendor is locked in (VIPA Profibus slaves are used in the worked example below), the configuration path is identical to native Omron slaves: import the device description, assign I/O, and map to CPU CIO words.

System Architecture Overview

The reference architecture is a single CJ1G-CPU45H rack with a CJ1W-PRM21 Profibus master mounted in the CPU rack. The DP master talks to a Profibus-DP segment terminated with 9.6 kbit/s to 12 Mbit/s auto-baud. VIPA SLIO-series or 050-series Profibus-DP slaves (third-party equivalents: Phoenix Contact Inline, Weidmüller u-remote, Beckhoff BK series) connect via Siemens-style Sub-D 9-pin PROFIBUS connectors with integrated termination switch.

CJ1G-CPU45H and the CJ1W-PRM21 Master Module

The CJ1G-CPU45H is a CJ-series high-performance CPU with the following relevant characteristics for Profibus integration:

• Program capacity: 60K steps
• I/O bits: 9,216 (CIO 0000-CIO 0511 plus expansion)
• Up to 3 expansion racks (total 40 I/O units including CPU)
• CPU Bus Units: up to 16 CJ1W- Bus Units per CPU (Profibus master consumes one slot)

The CJ1W-PRM21 Profibus-DP master (V1 class-1 master) occupies a single CPU Bus Unit slot and is mapped to a fixed CIO block. The module:

Set the rotary Unit No. switch on the front of the PRM21 to a free number (commonly 0) before mounting. The unit number determines the starting CIO address for the master module's status and control words.

Third-Party Profibus Slave Selection

With Omron DRT2 (DeviceNet) and SRT2 (CompoBus/S) slaves unavailable within the 4-week window, three Profibus-DP slave vendors are commonly evaluated for CJ1G projects:

For a Profibus-DP segment with 25 stations, VIPA and Phoenix Contact Inline blocks offer the best balance of price and module density. All three accept Siemens-compatible 9-pin Sub-D PROFIBUS connectors with onboard termination switch.

Profibus-DP Physical Layer Wiring

Profibus-DP cable must meet the EN 50170 cable specification (Siemens purple cable, 6XS1830-0AH10 or equivalent). Key requirements:

• Cable type: Profibus DP cable, 150 Ω nominal impedance, shielded twisted pair, purple sheath
• Connector: Sub-D 9-pin, Siemens 6ES7972-0BA12-0XA0 or compatible (with built-in termination resistor and switch)
• Topology: linear bus (daisy chain via the Sub-D connector through-ports); no stars, no stubs longer than 0.3 m at 12 Mbit/s
• Termination: 220 Ω resistor + 390 Ω pull-up/pull-down on both ends, enabled via the connector's slide switch
• Maximum segment length: 1,200 m at 9.6 kbit/s; 100 m at 12 Mbit/s

Pinout for the Sub-D 9 connector (per IEC 61158 / EN 50170):

CX-Profibus Configuration Tool

CX-Profibus is a CX-One add-on (license-managed through CX-One installer) used to build the DP master configuration. It is the only supported method for the CJ1W-PRM21 — there is no direct GSD-file text editor that the PLC will accept. CX-Profibus generates a .prm configuration that the PRM21 downloads on CPU RUN or via the dedicated PRM21 configuration transfer sequence.

The trial version of CX-One (CX-One-Trial) does not include a fully functional CX-Profibus module. The full CX-One license is required for production configuration. As a fallback, a Profibus configuration generated on a third-party master tool (e.g. Siemens STEP 7 HW Config) can be exported to a generic GSD/DPV1 text description, but the CJ1W-PRM21 still needs CX-Profibus to load it into the module's flash.

Reference: Omron Remote I/O product category for the broader CJ1/CJ2 remote I/O ecosystem.

Step-by-Step: Configure 25 VIPA Profibus Slaves on a CJ1G

1. Install CX-One and confirm CX-Profibus license. Launch CX-Profibus from the CX-One program group. The license must be activated; the trial version disables slave configuration.
2. Create a new project. Select File > New, choose CJ1W-PRM21 as the master, and assign a project name. CX-Profibus writes the master parameters to the project file.
3. Import the VIPA GSD file. Obtain the GSD file (e.g. VIPA_053-1DP01.gsd) from the VIPA product page. In CX-Profibus, select Tools > Install GSD File, point to the file, and confirm. The slave appears in the device catalog under the VIPA folder.
4. Add slaves to the segment. Drag the VIPA slave from the catalog to the DP master line. Repeat 25 times, assigning a unique Profibus station address (3 through 27 — addresses 0, 1, 2 are reserved; the master typically occupies 2 if no separate Class-2 tool is used, so starting at 3 is conventional).
5. Configure slot mapping. For each slave, double-click and select the I/O modules in the slots (digital input modules, digital output modules). The total I/O words per slave must match the physical module population. CX-Profibus reports module count and word count.
6. Set slave addresses on the hardware. Set the rotary address switch on each VIPA slave to the address assigned in step 4 (range 3-27). The address is read by the master during startup parameterization.
7. Save the project and export the master configuration. File > Save, then File > Export > CJ1W-PRM21 binary. This produces a configuration file the PRM21 stores in its non-volatile memory.
8. Transfer to the PRM21. With the CX-Profibus connected to the PLC via USB or Ethernet, select Online > Transfer Configuration to PRM21. The PRM21 writes the configuration to its flash and reboots in approximately 5 seconds.
9. Cycle power on the CPU. Power OFF then ON the CJ1G-CPU45H. The PRM21 starts up, performs slave parameterization, and enters cyclic data exchange (Data_Exchange state).
10. Verify in CX-Profibus diagnostics. Open the online view; all 25 slaves should show Data Exchange status. A slave that fails to parameterize will show Diagnostic or Not Connected.

CIO Address Allocation and PLC Programming

For a CJ1W-PRM21 set to Unit No. 0, the default I/O area is CIO 1500 through CIO 1524 (25 words). The exact starting CIO word follows the rule:

CIO start = 1500 + (Unit No. × 25)

Within this 25-word block, the first word is the master status/control area, and the remaining 24 words contain the consolidated I/O of all slaves in the order they were added in CX-Profibus. The total network must fit within 25 words. If 25 slaves × 2 words per slave = 50 words are required, the segment is too large for a single PRM21; either split the segment or add a second PRM21 with Unit No. 1 (CIO 1525-1549).

A ladder snippet for reading the first VIPA slave's inputs (assume slave 3, slot 0 = 8 DI, mapped to CIO 1501):

// --- Profibus PRM21 Unit No.0, Slave 3 inputs ---
// Bit 0.00 = CIO 1501.00, first input of slave 3
LD   P_On
AND  CIO 1501.00   // first DI from VIPA slave 3
OUT  W0.00         // map to work bit

For 16 PID loops at 10-15 ms update (a benchmark noted in field reports), the PRM21 segment can scan a 25-slave configuration in well under one Profibus cycle (typically 5-10 ms at 1.5 Mbit/s), so the bottleneck is the PLC scan, not the bus.

DeviceNet Alternative: EDS Workflow with CX-Integrator

If third-party DeviceNet slaves are the only available option (Phoenix Contact, Weidmüller, Beckhoff), the configuration path differs from Profibus in two respects:

1. The device description file is EDS (Electronic Data Sheet), not GSD.
2. The configuration tool is CX-Integrator (included in CX-One), not CX-Profibus.

Workflow for DeviceNet on CJ1G with CJ1W-DRM21:

1. Set the CJ1W-DRM21 rotary unit number (0 default). Default CIO range: 1500 + (Unit No. × 50) words.
2. Launch CX-Integrator, right-click the PLC > Start > Edit.
3. Import the EDS file of the chosen vendor (Phoenix Contact, Weidmüller, or Beckhoff).
4. Add the slave from the device tree to the DeviceNet network.
5. Assign the DeviceNet MAC ID (0-63, default 63 for new nodes) and the expected connections (Poll, Bit-Strobe, COS, or Cyclic).
6. Download to the DRM21 and cycle power on the CPU.

EDS-based configuration is conceptually similar to GSD: one text file per device, imported into a vendor-neutral tool, mapped to CPU I/O. Engineers familiar with Profibus will not find DeviceNet commissioning significantly harder or easier — the device-description format is the only meaningful learning curve.

Comparison: Profibus-DP vs. DeviceNet for CJ1G with 25 Slaves

Profibus-DP Slave Brand Selection Matrix

For a 25-station Profibus-DP build under time pressure, VIPA offers the shortest combined GSD-integration + delivery time. Phoenix Contact Inline is the second-best choice if VIPA is unavailable.

Commissioning Procedure and Verification

1. Pre-power check: Verify PROFIBUS termination is ON at the first and last node only, all Sub-D connectors are screwed down, and shield is continuous through each connector's shield clamp.
2. Power up the segment. Apply 24 VDC to each slave in any order. Each slave's bus-status LED should be ON (green); slaves with no bus activity flash red.
3. Connect the PRM21 configuration. With CX-Profibus online, click Live List. All 25 slaves should appear with their assigned station addresses (3 through 27).
4. Check Data_Exchange state. In the diagnostics window, confirm every slave is in Data_Exchange state, not Parameterization or Diagnostic. A slave stuck in Parameterization means a GSD/parameter mismatch.
5. Force a digital input. On the field side, short one input of slave 3 and confirm bit CIO 1501.xx toggles in CX-Programmer's watch window.
6. Force a digital output. Set bit CIO 1510.xx in CX-Programmer and confirm the corresponding output LED on the VIPA slave lights.
7. Monitor the bus scan time. CX-Profibus diagnostics reports the cycle time; a healthy 25-slave segment at 1.5 Mbit/s should run at 5-10 ms cycle time.

Troubleshooting Matrix

Field-Engineer Notes

• Always run the Live List in CX-Profibus before assuming a wiring fault. If all 25 slaves appear in the live list, the physical layer is healthy; if not, fix the cable before touching the configuration.
• Save the .prm configuration file in the project archive. PRM21 configuration is stored in module flash, but a fresh download takes less than 30 seconds and avoids a phone call to the OEM.
• If only CX-One Trial is available, a temporary workaround is to configure the slaves on a borrowed CX-Profibus license, export the binary, and use that binary to flash the PRM21 through a USB-to-serial cable and the CX-Profibus transfer utility. Trial software cannot legally be used to commission a production machine; purchase the license.
• For PID-intensive applications, the PRM21 supports up to 244 bytes input / 244 bytes output per slave and can sustain 10-15 ms update of 16 PID controllers with a properly sized network.