Omron C200HG Programming: Cable Selection and Serial Port Setup

C200HG PLC Family and Communication Architecture

The Omron C200HG belongs to the C200HX/C200HG/C200HE "alpha" generation of SYSMAC PLCs, a modular rack-based platform that superseded the original C200H. Despite its age, a large installed base still runs in process and discrete manufacturing, and engineers frequently encounter these controllers during fault-finding work without complete documentation on site. Communication with the controller is the first hurdle: unlike modern NX/NJ or CP-series controllers that expose USB and EtherNet/IP, the C200HG family relies on serial protocols routed through a physical port that varies by CPU model number.

Three physical attachment points exist across the alpha family:

• A 9-pin D-sub RS-232C port for Host Link (C-mode) communication on certain CPU modules.
• A peripheral port (Omron-proprietary mini-DIN style connector) used for programming devices and selected HMIs.
• An option slot that accepts a C200HW-COM-series communication board for RS-232C, RS-422, or RS-485 expansion.

CX-Programmer (and its predecessor SysWin) is the programming environment, and it expects the CPU to be in Host Link protocol when communicating through either the RS-232 port or the peripheral port. The protocol is set either in PLC Setup area DM parameters or by the CPU's onboard DIP switch bank. Reference documentation for the alpha family is consolidated in operation manual W303 (C200HX/C200HG/C200HE Operation Manual) and the ASCII Unit manual W306 (C200H-ASC11/21/31). Engineers upgrading legacy systems should also review the C200HX/HG/HE to CS1 Replacement Guide for pinout and register-mapping continuity.

CPU Model Identification and Onboard Port Availability

The CPU's full part number dictates the on-board communication resources. Field engineers should always read the model label on the front of the CPU module before assuming which cabling approach is valid, because the C200HG range shipped with three different port configurations in the same form factor.

RS232 Host Link Port on C200HG-CPU43

The C200HG-CPU43 integrates a Host Link RS-232C port directly on the CPU. The connector is a male 9-pin D-sub with the standard Omron Host Link pinout:

This port is intended for Host Link (C-mode) communication to a PC running CX-Programmer or SysWin, and may also be used for a Host Link HMI if the on-board port is free. Because the CPU43 has only one RS-232 port, if a panel or HMI is already wired to it you must either use the peripheral port for programming or fit a C200HW-COM board to free the on-board RS-232. Default parameters after a fresh install or after DIP switch 5 is toggled ON are listed in the DIP switch section below.

Peripheral Port Connection on C200HG-CPU33 and C200HG-CPU53

The peripheral port is an Omron-proprietary connector (often a 4-pin mini-DIN arrangement specific to SYSMAC alpha CPUs) used for programming devices such as the C200H-PR027 Programming Console and the CQM1-CIF02 / CPM1-CIF01 PC cables. The peripheral port defaults to Host Link protocol at a fixed baud rate, but the exact default depends on the CPU variant and the state of the DIP switch bank.

Two practical considerations on the CPU33 and CPU53:

1. There is no D-sub on the faceplate, so a direct PC serial cable cannot be plugged in. A converter or "smart" cable is mandatory.
2. Some installations reserve the peripheral port for a small text-display HMI. In that case, either disconnect the HMI for the duration of the fault-finding visit or use the C200HW-COM option slot for programming.

Cable Option 1: CQM1-CIF02 Smart Cable

The CQM1-CIF02 is the simpler of the two viable PC connections. It is a fully integrated "smart" cable:

• Host end: DB9 female, plugs into the PC's COM port.
• PLC end: Omron peripheral-port connector, plugs directly into the CPU33 / CPU43 / CPU53 peripheral port.
• Middle: a small inline black box containing the RS-232 level converter and Host Link protocol handler.

No additional cables are required. The CIF02 enumerates as a transparent Host Link bridge, so CX-Programmer sees a standard C-mode connection. The CIF02 works with the entire C200H alpha family (CPU33, CPU43, CPU53) and is also widely used on CQM1 and CP1E controllers. Approximate list price on the European industrial supply market is around £200. The part is sometimes also supplied under the equivalent designation used by Omron-Europe for newer shipments, but the original Omron catalog number remains CQM1-CIF02.

Cable Option 2: CPM1-CIF01 Converter

The CPM1-CIF01 is a two-piece solution consisting of a short adapter plus a separate serial cable:

• Adapter: DB9 female on the front face; approximately 150 mm pigtail terminating in an Omron peripheral-port connector on the rear.
• Separate cable: a straight-through DB9 male-to-female serial extension (commonly the same cable shipped with CVM1 CPUs), wired 1-to-1, 2-to-2, 3-to-3, 4-to-4, 5-to-5, 6-to-6, 7-to-7, 8-to-8, 9-to-9 with shield on the shell.

This combination is functionally equivalent to a CIF02 for the C200H alpha family. It is attractive when an engineer already owns the CVM1 lead, because the only additional item required is the CIF01 adapter body itself.

C200HW-COM Communication Boards

If both the on-board RS-232 and the peripheral port are already occupied by an HMI, fitting a C200HW-COM-series communication board into the CPU's option slot is the cleanest solution. Common variants include:

The COM02 is the most cost-effective way to add a Host Link RS-232 port to a CPU33 or CPU53, typically available for around £60 from industrial distributors. For more detail on option-board installation, including DIP switch settings for the COM port itself, refer to the W303 operation manual.

DIP Switch Configuration and Host Link Protocol Parameters

The CPU faceplate carries a small 6-position DIP switch bank (SW1 to SW6) located behind a removable cover. The switch state is read only at power-up, so any change requires a power cycle to take effect. The most communication-relevant switch is SW5:

When SW5 is set to ON and the CPU is power-cycled, the on-board RS-232 port is forced to the Host Link default parameter set, overriding whatever has been written into the PLC Setup area (DM). This is the recommended first action when arriving on site to fault-find: turn SW5 ON, cycle power, and try connecting. Once communication is established, SW5 can be returned to OFF and the PLC Setup reviewed for the actual in-service configuration.

Host Link defaults applied by SW5 = ON are:

CX-Programmer Connection Procedure

Once the cable type and DIP switch state are settled, the PC-side configuration in CX-Programmer is straightforward:

1. Launch CX-Programmer. From the PLC menu, choose Change Model and select C200HG (CPU type auto-detects when online).
2. Open PLC > Auto Online. The dialog box will display detected COM ports. Choose the COM port the cable is connected to (typically COM1 on legacy laptops; use a USB-to-serial adapter verified to deliver 5 V levels on pins 4 and 7 if no native port exists).
3. Set driver type to SYSMAC WAY (Host Link C-mode).
4. Confirm the serial parameters: 9600, 7, E, 2, unit number 00.
5. Click Connect. CX-Programmer will issue a Host Link status read and display the CPU model, operating mode, and project memory size.
6. If communication fails, verify the unit number first. A non-zero unit number is a common field issue when a C200HW-COM board has been added with a different rotary switch setting.

For a permanent C200HW-COM02 connection, the COM02 board itself has its own rotary switch for the Host Link unit number, and its own DIP switch to select RS-232 vs RS-422/485. These are documented in section 6 of the W303 manual.

SWP Project File Recovery and Conversion

Customers occasionally hand over a project as a .SWP file, the native format of the now-obsolete SysWin programming software. CX-Programmer's File > Open function will attempt to import a SWP file directly, and the bundled File Conversion Utility (accessible from the Windows Start menu under the Omron folder) can perform a batch conversion of legacy project files.

Symptoms of a corrupted SWP file include:

• CX-Programmer aborts the import with a generic file-format error.
• The File Conversion Utility hangs partway through conversion (typically at the symbol table section).
• SysWin refuses to open the file and reports the header as invalid.

Empirical recovery technique when the header is the only damaged section: open the .SWP file in a plain-text editor such as Notepad, perform a no-op File > Save (or save-as to a new name), and close. The text-mode re-write normalizes line-ending characters and re-emits a valid header. CX-Programmer and SysWin can then load the file, although program-body password protection (if present) will still block source viewing without the original password.

If the project was created on a CVM1 (as in the typical CVM1 to C200HG migration path), the program structure is largely compatible. Differences are limited to certain advanced instructions and the SFC syntax. The replacement guide referenced earlier lists every instruction that requires manual conversion.

Verification and Field Commissioning Checklist

Before declaring the connection healthy, run through the following checks in order:

1. Visually confirm the CPU model number against the port table above.
2. Confirm the DIP switch cover is in place and SW5 has been cycled through OFF → ON → OFF to re-read the PLC Setup.
3. Power-cycle the CPU and observe the front-panel indicators: PWR (green) on, RUN (green) or ERR (red) according to the program state.
4. Connect with CX-Programmer and read the CPU model. A correct echo confirms the unit number, baud rate, and protocol all match.
5. Force a single bit (e.g., CIO 100.00) ON from the software and confirm the corresponding output module LED illuminates.
6. Disconnect, return SW5 to OFF (unless the customer prefers the default behaviour), and reseal the DIP cover.

Frequently Asked Questions