Omron C200HS LK201-V1 Host Link: Proface HMI Integration Guide

1. System Overview and Component Identification

The integration described in this reference combines four field assets on a single Omron Host Link segment:

• Omron C200HS CPU — the controller that owns all DM and CIO memory.
• Omron C200HS-LK201-V1 — a rack-mounted Host Link module providing one RS-232C channel toward the HMI and one toward the PC.
• Proface touch screen — the operator interface, configured with a "System Area" of DM100.
• Barcode scanner — ASCII string source that must reach both the PLC and the PC.

The C200HS does not execute Protocol Macro (PMCR) instructions; that capability was added on the CJ1/CS1 platforms. Any serial string handling on this generation must either be offloaded to an intelligent module (such as the C200H-ASC02 ASCII/BASIC module) or be passed through the HMI's pass-through function if the HMI supports it.

2. LK201-V1 Front-Panel DIP Switch Configuration

The LK201-V1 module has two rotary switches (SW1, SW2) on the front panel for the Host Link unit number and two banks (SW3, SW4) that select baud rate and command level. Field-confirmed values for a Proface touch screen at 9600 baud are listed below.

SW3 decode (Host Link standard, valid for C200HS-LK201-V1):

SW4 select bits for Host Link frame format:

3. Host Link Communication Parameters

Omron Host Link (C-mode) is a polled master/slave ASCII protocol running at RS-232C levels. For the C200HS-LK201-V1 the recommended baseline is:

A typical Host Link read of DM0100 is sent as the following 17-byte ASCII frame:

@00RD01000001*

Where:

• @ — start of text
• 00 — unit number (matches SW1/SW2)
• RD — read DM area command
• 0100 — starting word (DM100)
• 0001 — number of words
• * — terminator identifier
• \r (0x0D) — carriage return

For the C200HS, the address encoding is 4-digit BCD for DM, IR/CIO, HR, AR, LR, and T/C flag areas. The FCS (frame check sequence) byte is computed as the two's complement of the lower 8 bits of the sum of every ASCII byte from @ through the byte just before *.

4. Proface System Area and DM Register Mapping

The Proface "System Area" is a reserved DM block that the HMI writes automatically to indicate screen number, control status, error codes, and the current values of any numerical display or input field bound to a DM address. Configuring the System Area to DM100 allocates a contiguous block starting at DM100.

Writes to DM100 and the surrounding block are expected behavior; the HMI is updating them on every screen change and on every numerical input. The PLC ladder should treat DM100–DM109 (or however many words the System Area spans) as HMI-owned and never overwrite them from a MOV or arithmetic instruction.

5. Why DM100, DM260, DM6000–DM6030 Are Changing

Three independent writes explain the field observations:

1. DM100 — Proface System Area base. The HMI is writing screen number and status here every cycle. This is normal.
2. DM260 — Falls inside an expanded user-data portion of the System Area (offset 160 from DM100) or is being used as a numeric display/entry part's address inside the GP-Pro project. Confirm the System Area size in the GP-Pro screen setup; default can be 10, 20, or 30 words. A value showing up at DM260 implies the System Area was expanded or a control was bound to a specific DM address within it.
3. DM6000–DM6030 — C200HS Error History storage area. Per the C200HS Operation Manual (W130-E1-□, page 55), this range records non-fatal error log entries when error history is enabled in PLC Setup. Any recorded communication error, syntax error, or expansion rack fault will be timestamped and written here. Values appearing here are the PLC's own log of the very Host Link error the HMI may also be showing.

6. C200HS-LK201-V1 Host Link Frame: Quick Diagnostic

Use a passive RS-232C tap (Y-cable or breakout) to monitor the LK201-V1 port with a laptop running a terminal at 9600-7-E-2. Expected traffic after a Proface screen change:

PC -> LK201 : @00RD00100001F7*<CR>
LK201 -> PC : @00RD001000014000010000F6*<CR>

Common error returns that will populate DM6000:

7. Barcode Scanner Integration Options

On a C200HS, three viable paths exist for getting ASCII barcode data into the controller:

7.1 Proface Pass-Through (preferred, no extra hardware)

Many Proface GP-series panels expose a "Bar Code" or "Pass-Through" part that writes the scanner's serial string into a consecutive DM block. The PLC then sees the scan data in ladder-usable ASCII words. The Proface serial port (RS-232C) is configured for the scanner, the LK201-V1 port is independent. Verify in the GP-Pro project whether the target firmware supports this — older GP units do not.

7.2 C200H-ASC02 ASCII/BASIC Module

The C200H-ASC02 is a special I/O module that runs a BASIC program to parse incoming ASCII strings and write them into allocated DM words. It occupies one slot in the C200HS rack, requires its own RS-232C port configuration, and a BASIC program written with the ASC02 Support Software. The C200HS ladder reads the result words with normal MOV(021) instructions.

7.3 Direct PC Routing (no PLC involvement)

If the objective is strictly "barcode → PC," connect the scanner to the Proface and use the Proface's Pass-Through feature, or connect the scanner directly to the PC's COM port. The PLC is bypassed entirely. This is the simplest path when the PC is the only required data sink.

8. PC Serial Connection Wiring (LK201-V1 25-pin ↔ PC 9-pin)

The LK201-V1 presents a DB-25 male RS-232C port. The PC standard COM port is DB-9 male. A null-modem (crossover) cable is required because both are DTE.

Recommended null-modem wiring for Host Link use (only TD, RD, SG, plus looped handshakes):

DB-25 (LK201)        DB-9 (PC)
   2  TD  -----------  3  RD
   3  RD  -----------  2  TD
   4  RTS  --+-------  8  CTS
   5  CTS  --+--loop--  7  RTS
   6  DSR  -----+-----  4  DTR
  20  DTR  -----+-----  6  DSR
   7  SG  -----------  5  SG
   1  FG  -----------  Shell

9. CX-Programmer Address Encoding (CIO vs DM)

When the user asked "how do I write a program to use the Host Link address?" the answer is that the address numbers 3809 to 3855 must be interpreted in the correct memory area. C200HS has two parallel numbering schemes:

Registers 3809–3855 do not correspond to any standard C200HS area. They are most likely Proface-internal offsets into the System Area, or a misread of the GP-Pro address printout (GP-Pro often shows addresses without the leading area letter). Confirm in the Proface project what data type (binary bit, BCD word, ASCII string) each address carries, then map it to the corresponding CX-Programmer address type:

• For a Proface word write that needs to control a C200HS output: import the value with MOV(021) from DM into CIO, then OUT to the physical output.
• For a bit display: use TST(350) or LD/AND with the corresponding CIO bit.

Example ladder snippet that reads the System Area's first user word (DM103) and turns on CIO 100.00 if the value is greater than 100:

|    LD     P_On              Always-on contact (differential)
|    MOV(021)  DM103  DM200  Copy HMI word to a work area
|    CMP(020)  DM200  #0100  Compare to 100
|    AND       25505          Greater-than flag from CMP
|    OUT       100.00         Drive output

10. PLC Setup Parameters for Host Link

The C200HS PLC Setup (DM 6600–DM 6644) holds the port configuration that the CPU applies to its built-in RS-232C port and the LK201-V1's port. Relevant words for a Proface installation:

For the LK201-V1 in an expansion rack, similar setup is allocated in the words corresponding to the slot's installed module. Refer to the C200HS Operation Manual for the exact mapping; on a 3-slot expansion the LK201-V1 typically uses DM 6700–DM 6704 for its port parameters.

11. Proface GP-Pro Project Configuration

1. Open the GP-Pro EX (or older GP-PRO/PBIII) project.
2. Select System Settings → I/O Driver → Omron SYSMAC CS/CJ/CP (or "Omron Host Link C-Mode" for older units).
3. Set the host address to 00 (must match SW1=0, SW2=0).
4. Set communication to 9600, Even, 7, 2.
5. Open System Area Settings, enable the System Area, and set the starting word to DM100. Set the area size to the smallest value that covers all HMI-owned words (10 is a safe minimum).
6. Bind numeric input/display parts to DM103+ for any data the PLC must read or write.
7. For barcode pass-through, add a "Bar Code" part in the screen and bind it to a DM block large enough to hold the longest expected scan (e.g., 20 words for a 40-character ASCII string).
8. Transfer the project to the panel over USB or serial and cycle power on the LK201-V1 and the panel together.

12. Verification Procedure

1. Power the C200HS rack and confirm the RUN LED is solid green.
2. Watch the LK201-V1 RD/TD LEDs during Proface polling. Each Host Link read should produce a brief RD flash followed immediately by a TD response.
3. From the Proface, navigate to a screen that displays a numeric part bound to DM103. Force DM103 from CX-Programmer (online → Monitor → set value 1234) and confirm the Proface display updates within one scan cycle.
4. Trigger a screen change on the Proface and confirm DM100 changes to the new screen number (CX-Programmer online monitor).
5. Read DM6000 from CX-Programmer and verify that no new error codes have been appended since the last clean test.
6. Run a Host Link "Test" from the Proface diagnostic menu — it should report "Communication OK" with the unit number 00.
7. Test barcode pass-through by scanning a known string and confirming it appears in the bound DM block.

13. Troubleshooting Matrix

14. Field Commissioning Notes

• Always verify the LK201-V1 unit number (00–31) is unique on the segment. Two modules set to 00 will collide on every poll.
• The C200HS does not support PMCR(260) instructions. Do not attempt to write a Protocol Macro sequence on this platform.
• When the Proface System Area is set to DM100, never use DM100–DM100+(N−1) inside the ladder for anything other than reading HMI status. Overlay will cause the HMI to overwrite ladder writes within one cycle.
• If the C200HS is communicating with the Proface on the LK201-V1 port, the built-in RS-232C port of the CPU remains free for CX-Programmer and remains at 9600-7-E-2 by default. Do not change it to Toolbus (CX-Programmer default is "Toolbus" — switch to "Host Link" in the driver setup before connecting).
• DM6000+ error log retention is across power cycles. Clear it after every major fix to keep the log meaningful.
• For barcode pass-through on legacy GP-377, GP-477, and GP-577 series panels, consult the GP-Pro part library — not all barcode parts support serial pass-through to a Host Link-bound DM area.