Installing GSD Files in CX-Profibus for CJ1W-PRM21 Master

Overview

Adding a third-party PROFIBUS-DP slave such as the Carlo Gavazzi WM14-96 power analyzer to an Omron CJ1M-CPU13 PLC requires a PROFIBUS master module (the CJ1W-PRM21), the CX-Profibus configuration utility, and the slave's vendor-supplied GSD file. Unlike Siemens STEP 7, where the GSD importer is exposed directly in the hardware catalog, the Omron toolchain splits configuration between CX-Profibus (network editor) and CX-Programmer (ladder / ST). This reference walks through the full procedure: importing the GSD, attaching the slave, mapping I/O to PLC memory areas, and confirming cyclic data exchange.

System Architecture

The reference configuration has the following topology. Each device has a unique PROFIBUS station address, and the WM14-96's GSD file supplies the supported baud rate, diagnostics, and module slot layout.

The CJ1W-PRM21 occupies a single slot on the CJ1 CPU rack (or an expansion rack within the same bus). It uses the standard CJ1 I/O backplane interface and appears to the CPU as a special I/O unit with allocation words in the CIO 1500+CIO 25*n region plus auxiliary words in CIO 1500+100 +CIO 25*n (where n is the unit number 0-15 set by the rotary switches on the module). For unit number 0, the default starting word is CIO 1500 with the auxiliary area starting at CIO 1600.

Prerequisites

1. Hardware
   • Omron CJ1M-CPU13 (or any CJ1M / CJ1G / CJ1H CPU that supports the PRM21).
   • Omron CJ1W-PRM21 PROFIBUS-DP Master Unit (related part CJ1W-PRT21 is the slave unit; datasheet format applies for documentation). Source the master and confirm the unit version (V1.0+ recommended for clean GSD import).
   • Carlo Gavazzi WM14-96 power analyzer with the manufacturer GSD file (file extension .GSD or .GSE plus .BIT bitmap).
   • PROFIBUS-DP cable (purple, type A, 120 Ω characteristic impedance) and two terminating resistors (one enabled at each physical end of the segment).
2. Software
   • CX-Programmer version 9.x (the version must be compatible with the CPU; the CJ1M-CPU13 is supported by CX-Programmer 5.0 and later).
   • CX-Profibus version 2.x or later (must match the CX-Programmer release; Omron ships a bundled CX-One suite that includes both). Download from the Omron Downloads Library with a valid license.
   • CX-Server runtime or a SYSMAC Gateway connection (USB / serial / Ethernet, depending on CPU) for online transfer.
3. Documentation
   • Carlo Gavazzi WM14-96 user manual (for module-slot definition and supported data formats).
   • Omron CJ1W-PRM21 PROFIBUS-DP Master Unit Operation Manual (Cat. No. W409-E1 or later revision).
   • CX-Profibus Operation Manual (Cat. No. W06E-EN-01 or current revision) for the installed version.

Understanding the GSD File

The GSD (General Station Description) is a vendor-supplied ASCII file that defines a PROFIBUS slave's identity and behavior. The CX-Profibus parser reads the following sections:

Place the GSD, any GSE (extension) and BIT (bitmap) files in a dedicated folder such as C:\PROFIBUS\GSD\WM14-96\ so CX-Profibus can re-read them if you ever rebuild the catalog. The WM14-96 ships its GSD as a single file; verify the file is not blocked by Windows (right-click → Properties → Unblock if it was downloaded from the vendor site).

Installing the GSD File in CX-Profibus

Unlike STEP 7, CX-Profibus does not auto-scan a system folder. The GSD is imported explicitly into the local device catalog.

1. Start CX-Profibus from CX-One or as a standalone application.
2. From the menu, open View → Device Catalogue. A tree view opens in the workspace with the default Omron master list and any previously imported GSDs.
3. Click the Install GSD Files button (or use the toolbar icon labeled Install GSD).
4. Browse to the folder containing the WM14-96 GSD file. Select the .GSD file and confirm.
5. CX-Profibus parses the file, checks the Ident_Number, and adds the WM14-96 to the catalog under the assigned vendor folder. A confirmation dialog lists the imported module names and the number of slots / modules exposed.
6. If the GSD references a bitmap (*.bmp or *.dib), place it in the same folder; the import wizard binds the image automatically.

Creating the Project and Attaching the WM14-96

1. In CX-Profibus select File → New Project, name it, and choose the CPU family CJ Series with the corresponding master type. The CJ1W-PRM21 is already in the default catalog, so it can be dropped onto the PROFIBUS line directly.
2. Double-click the master icon to set the PROFIBUS address (default is 1) and baud rate. The CJ1W-PRM21 supports all standard PROFIBUS baud rates from 9.6 kbps to 12 Mbps. For the WM14-96 with a 96 x 96 mm panel-mount analyzer, 1.5 Mbps is the typical industrial choice with a 100 m segment.
3. Open the Device Catalogue again, navigate to the imported Carlo Gavazzi folder, and drag the WM14-96 entry onto the bus line. Assign station address 2 (this must match the address set in the WM14-96's front-panel menu under Communication → Profibus → Address).
4. Right-click the WM14-96 station and open Slave Properties. Verify:

Save the project. The compiled configuration is the binary file CX-Profibus downloads to the CJ1W-PRM21's flash memory via CX-Server (or the SYSMAC gateway).

Mapping PROFIBUS I/O to CJ1 Memory

The CJ1W-PRM21 exchanges cyclic data with the CPU through a fixed I/O area. The number of words depends on the master's configuration and the slaves' I/O footprint. For the WM14-96 with a 16-input / 16-output module, the PRM21 reserves 16 input words and 16 output words of process data. By default these are mapped into the CIO area allocated to the unit number set by the front-panel rotary switches.

From CX-Profibus, open Project → Master Settings → CPU I/O Allocation to read the exact word ranges the master expects to use; copy these values into a symbol table in CX-Programmer. The WM14-96 measurement block typically appears as 16 contiguous input words starting at the first allocated input word; consult the GSD's module list to confirm byte ordering (PROFIBUS is big-endian for word values).

Ladder Integration in CX-Programmer

Once the master configuration is downloaded, switch to CX-Programmer and write ladder to consume the measurements. The following snippet reads apparent power (kVA) from the WM14-96 as a signed 32-bit value at input word offset 4 (example mapping - verify against the actual GSD module definition):

LD     P_On
MOV(021) &0      D100    ; clear D100/D101 accumulator on first scan

; --- Apparent power reading (kVA, S7 format float, 4 bytes) ---
LD     P_On
MOVR(560) CIO1504 D200  ; copy 32-bit real from CIO 1504 to D200

For word-level integers (e.g., voltage L-N in tenths of a volt), use direct CIO addressing:

LD     P_On
MOV(021) CIO1500 D50   ; V L1-N raw value
MOV(021) CIO1501 D51   ; V L2-N raw value
MOV(021) CIO1502 D52   ; V L3-N raw value

Add scaling math if the GSD specifies a multiplier. For example, with a stated resolution of 0.1 V the engineering value is D50 * 0.1. The FLT(452) and MLS(491) instructions convert and scale without consuming a real-math option board.

Downloading the Configuration

1. In CX-Profibus choose Online → Download to Master. Select the SYSMAC Gateway connection (USB / Ethernet / serial) to the CJ1M-CPU13 rack. The PRM21 must be in Stop state for download; the wizard prompts for confirmation.
2. Wait for the Download complete message. The PRM21 reboots with the new configuration (takes approximately 5-8 seconds).
3. Place the master back in Operate from the same dialog or by cycling the rack power if the wizard requires it.
4. Transfer the CX-Programmer project to the CPU. The PROFIBUS configuration and the ladder project are downloaded independently - the master only uses the PROFIBUS binary, the CPU only uses the ladder. Both must be present for cyclic exchange.

Verification and Commissioning Checks

Run these checks in order. A green LED status at every step is required before moving to the next.

Troubleshooting Matrix

Field-Proven Caveats

• Address the WM14-96 before wiring power. The address is stored in non-volatile memory on Carlo Gavazzi analyzers, but writing it requires entering the password (default 1000) on the front panel. A wrong address that does not match the CX-Profibus configuration will cause a permanent Param Fault on the master.
• Reserve one termination resistor at each physical end. On a single-slave bus, both terminators are on the PRM21 and the WM14-96. Some Carlo Gavazzi units ship with the internal terminator enabled - check the WM14-96 manual, position TER switch, before adding an external resistor.
• DM capacity on the CJ1M-CPU13. The CPU has 32 Kwords of DM. If you plan to log 50+ power-quality values, scale to engineering units immediately in the first scan and move historical buffers to an HMI or SCADA archive - DM will fill quickly.
• PRM21 firmware version. The GSD import routine is sensitive to the PRM21 firmware version. If the catalog refuses to accept a recent WM14-96 GSD, update the PRM21 firmware via the CX-Profibus downloader (the tool includes a firmware update option). Omron publishes the latest revisions on the Omron Downloads Library.
• PROFIBUS-DP vs. PROFIBUS-PA. The WM14-96 family is PROFIBUS-DP; do not attempt to connect a PA device to the same segment. The CJ1W-PRM21 is a DP master only.