Configuring Vijeo Citect v6.1 to Omron CJ1M via Serial Host Link

1. Overview

This reference documents the field-proven procedure for establishing reliable serial communication between Vijeo Citect v6.1 (Schneider Electric's SCADA/HMI runtime, originally Citect) and an Omron CJ1M-CPU11 programmable controller using the Host Link (Sysmac Way) protocol. The CJ1M does not appear by name in the legacy Citect driver catalogue, but its communication subsystem is fully compatible with the CJ1/CS1 family and exposes the same Host Link command set used by the older C-series, so the OMRON C200H driver configured for Sysmac Way is the correct selection.

Three configuration elements must converge before I/O is exchanged:

1. The PC serial port must be wired to the CJ1M RS-232C port using a semi-universal crossover cable (or a manufacturer-approved equivalent such as the Omron XW2Z family for peripheral-port installations).
2. The PLC must be placed in Host Link mode (not Toolbus, not NT Link) at a baud rate that matches the Citect port configuration.
3. The Citect project must reference the C200H driver with matching serial parameters, unit number, and protocol framing.

2. Prerequisites

3. CJ1M-CPU11 Communication Hardware

The CJ1M-CPU11 ships with two physical communication interfaces, and selecting the correct one is critical because Citect must terminate its serial session on the same port that is configured for Host Link inside the PLC.

For a direct Citect-to-PLC serial cable, terminate on the built-in RS-232C DB9 port. Verify the port location against the CJ1M CPU11 Datasheet (Cat. No. R142-E1) before wiring, because the CJ1M-CPU12/CPU13/CPU22/CPU23 variants relocate or duplicate these connectors.

4. Driver Selection: C200H (Sysmac Way) Protocol

The Citect driver chooser presents several Omron entries; the correct mapping is governed by the wire protocol, not the marketing product family.

The CJ1M and CS1 share the same Host Link command interpreter, so any reference to "CS1" in Citect documentation applies equally to CJ1. However, when the wire is RS-232C and the goal is point-to-point SCADA polling without FINS routing, the C200H driver is the most direct and least failure-prone path.

5. Host Link Protocol Frame Format

Sysmac Way uses an ASCII frame bounded by @ on the host-to-PLC side and response frames starting with @ followed by a two-character node number, command code, status/header, and FCS checksum terminated by *CR. Citect handles the frame formatting internally once the driver and parameters are set, but understanding the frame helps when interpreting raw traffic on a serial line analyzer.

Host → PLC:  @  0  0  RR  00  00  00  01  FCS  *  CR
PLC → Host:  @  0  0  RR  00  FCS  *  CR      (normal completion)
PLC → Host:  @  0  0  RR  xx  FCS  *  CR      (xx = non-zero error code)

Common Host Link error codes returned by the CJ1M:

6. Cable Wiring: Semi-Universal RS-232C

The CJ1M-CPU11 RS-232C port is wired as a DTE (Data Terminal Equipment) with a DB9 male connector on the front face. A standard PC COM port (DB9 male) is also DTE, so a one-to-one straight cable will not work: at minimum, TX and RX must be crossed. A semi-universal cable additionally loops back the hardware handshaking lines so the PC believes the device is ready (DSR high, CTS high) and asserts DTR/RTS that the PLC sees as valid.

The following SVG illustrates the same wiring for quick reference at the panel:

Maximum recommended cable length for RS-232C at 9600 bps is 15 m (50 ft). If the panel layout forces a longer run, drop to an RS-422 option board (CP1W-CIF11) and the Citect OMROM C200H-RS422 driver entry, or move the Citect server closer to the panel.

7. PLC Setup: Enabling Host Link on CJ1M

Use CX-Programmer to confirm the built-in RS-232C port is set to Host Link. The CJ1M stores these parameters in PLC Setup → Host Link Port (peripheral settings are a separate menu). The key fields are:

1. In CX-Programmer, go online and open PLC → Edit → PLC Setup → Host Link Port.
2. Confirm Word 144 = 00 (Host Link). If it shows 01 (Toolbus) or 02 (NT Link 1:N), Citect will silently time out.
3. Set Word 145 to the desired baud rate. Leave at 9600 (Word 145 = 00) for first commissioning.
4. Set Word 146 to 00 for the standard 7-E-2 frame.
5. Set Word 147 to 00 for the default unit number, unless multiple Host Link devices share the line.
6. Transfer the setup to the PLC and cycle power.

8. Citect v6.1 Project Configuration

Configure the Express Communication Wizard or manually edit the INCLUDE files. Manual configuration is more transparent for troubleshooting.

1. Open the Citect Project Editor and select Communications → Boards. Create or edit the PC board:

   Board Name     = BOARD1
   Board Type     = COM (serial)
   Port           = COM1
   I/O Device     = 0
   Special Opts   = (none)

2. Open Communications → Ports and create a matching port:

   Port Name      = PORT1
   Board Name     = BOARD1
   Number         = 0  (zero-based index of COM1)

3. Open Communications → I/O Devices and create the PLC:

   I/O Device Name  = PLC1
   Number           = 0
   Address          = 0              (Host Link unit number)
   Protocol         = SysmacWay      (the Citect protocol string for C200H)
   Port Name        = PORT1
   Baud Rate        = 9600
   Data Bits        = 7
   Parity           = E (Even)
   Stop Bits        = 2
   Special Opts     = (blank)

4. Open Communications → Clusters:

   Cluster Name  = CLUSTER1
   I/O Device    = PLC1
   Enable        = Yes

5. Compile and run the Citect project. The driver DLL OMRH.DLL loads under [SYSTEM]"Citect Drivers".

If you prefer the Express wizard, the equivalent selections are: Vendor = OMRON, Driver = C200H (Sysmac Way), Port = COM1, Baud = 9600, Parity = Even, Data = 7, Stop = 2.

9. Citect Tag Address Mapping for CJ1M

The C200H Sysmac Way driver uses Omron-style area tags. Map Citect variable tags to PLC memory areas with the prefix syntax shown:

For bit-level tags, append a dot and bit number (0–15) to the word address, e.g. DM00100.05 for bit 5 of D100. The driver performs the word read/write and extracts the bit.

10. Verification and Diagnostics

After the project compiles and runs, perform these verification steps in order:

1. Hardware verification — observe the CJ1M RS-232C port LED. On the CPU11, the LED labeled RD should flicker when the Citect server polls. Steady dark = cable or baud mismatch.
2. Citect Kernel log — open Citect32.exe with kernel logging enabled (Kernel = 1 in Citect.ini). Look for lines containing the I/O device name:

   [I/O Devices]
   PLC1: Port opened: COM1 (9600,7,E,2)
   PLC1: Unit 0: Connected
   PLC1: RR 00 00 00 01 → OK

   A "FCS error" or "timeout" line indicates framing problems.
3. Tag test — open the Citect Cicode debugger or a watch window, force a known value into W000100, and confirm the corresponding bit toggles in CX-Programmer's watch window online.
4. Bidirectional test — write a value from CX-Programmer to DM00200 and read it from Citect as DM00200. A mismatch points at the tag address, not the wire.
5. Stress test — leave the system polling for 30 minutes. Host Link frames lost at 9600 bps typically surface as FCS errors under EMI from VFDs or welding inverters. If errors rise above 0.1%, add shielded cable, ferrite beads, or move to 19,200 bps with shorter cable.

11. Troubleshooting Matrix

12. Frequently Asked Questions