AutomationDirect Click PLC (C0 series)
Register map(s) for this device, each at the trust rung it earned. Addresses are 0-based
as on the wire. Word order and scaling are confirmed at the hardware-verified rung and at no rung below it.
interop-verified
Read + decoded cleanly over a real network vs an independent third-party Modbus test server (transport and framing; reads are remapped into the server's register window, so the map's own addresses are NOT exercised). Does NOT prove word order/scaling against the actual device.
| point | address (0-based) | type | scale | unit |
|---|
| ds1 | 0 | I16 | 1 | |
| ds2 | 1 | I16 | 1 | |
| ds3 | 2 | I16 | 1 | |
| ds4 | 3 | I16 | 1 | |
| ds5 | 4 | I16 | 1 | |
| ds6 | 5 | I16 | 1 | |
| ds7 | 6 | I16 | 1 | |
| ds8 | 7 | I16 | 1 | |
| ds9 | 8 | I16 | 1 | |
| ds10 | 9 | I16 | 1 | |
| ds11 | 10 | I16 | 1 | |
| ds12 | 11 | I16 | 1 | |
| ds13 | 12 | I16 | 1 | |
| ds14 | 13 | I16 | 1 | |
| ds15 | 14 | I16 | 1 | |
| ds16 | 15 | I16 | 1 | |
| ds17 | 16 | I16 | 1 | |
| ds18 | 17 | I16 | 1 | |
| ds19 | 18 | I16 | 1 | |
| ds20 | 19 | I16 | 1 | |
link settings as documented (unverified): RTU/ASCII/TCP; default 38400 8O1; unit ID 1; FC 01,03,05,06,16; Port 1 (RS-232) has fixed settings (38400 bps, Odd parity, 1 stop bit, Address 1, Modbus RTU slave only). Port 2 (RS-232) and Port 3 (RS-485) have configurable settings with default baud 38400, default parity Odd, default stop bit 1, default address 1. Port 1 (Ethernet) supports Modbus TCP.
bench facts as documented (unverified)
| terminals | Port 3: 3-pin terminal block (+, -, LG). Port 1 & 2: 6-pin RJ12. Port 1 (Ethernet): 8-pin RJ45. |
| A/B polarity | Port 3 RS-485: Pin 1 is + (Plus) Signal A, Pin 2 is - (Minus) Signal B. |
| termination | Add a termination resistor between the + and - terminals on Port 3 and on the last device. Resistance needs to match the impedance of the communication cable. |
| connector | 6-pin RJ12, 3-pin Terminal Block, 8-pin RJ45 |
| isolation | Non-isolated (Port 1 RS-232C, Port 2 RS-232C, Port 3 RS-485) |
| shield/ground | Port 3 Pin 3: LG Logic Ground (0 V) |
| wiring notes | RS-232 ports can provide 5VDC to power one monochrome Micro-Graphic panel. |
| broadcast | supported |
| protocol notes | Ethernet Port 1 can communicate with up to 4 servers (slaves) and up to 3 clients (masters) simultaneously. Use a repeater if connecting more than 32 slaves to Port 3. |
| identification notes | Modbus addresses can be verified using the Address Picker in the CLICK programming software. |
| power | RS-232 ports can provide 5VDC power for one monochrome C-more Micro-Graphic panel. |
| doc revision | 6th Edition, Rev. Q – C0-USER-M |
field reports — community-sourced, unverified (checked 2026-06-11)
- The built-in RS-232 serial ports (Port 1 and Port 2) operate in half-duplex mode only, meaning they cannot simultaneously transmit and receive data. This hardware limitation can cause incoming ASCII data (e.g., from scales or barcode readers) to be missed or corrupted if the target device responds immediately without a delay. [source]
- Modbus addressing offset confusion: Koyo Click data register numbering starts at DS1 (not DS0), which maps to Modbus 0-based offset 0 (or 1-based 400001). Some third-party software packages or dataloggers that do not support 6-digit Modbus addressing or have a 32767 address limit fail to read registers like DS11 (Modbus address 10) when users mistakenly try to address them as 400011. [source]
- confirmed: Port 1 (RS-232) has fixed settings (38400 bps, Odd parity, 1 stop bit, Address 1, Modbus RTU slave only) — confirmed by AutomationDirect CLICK Serial Setup guide and C0-USER-M manual
- confirmed: Port 3 RS-485: Pin 1 is + (Plus) Signal A, Pin 2 is - (Minus) Signal B, Pin 3 is LG Logic Ground (0 V) — confirmed by CLICK PLC Hardware User Manual (C0-USER-M) and wiring diagrams
- confirmed: Ethernet Port 1 can communicate with up to 4 servers (slaves) and up to 3 clients (masters) simultaneously — confirmed by Chapter 4 of the CLICK PLC Hardware User Manual (C0-USER-M)
- confirmed: DS1 maps to Modbus 0-based address 0 (or 1-based 400001) — confirmed by CLICK PLC Modbus TCP Communication with Python OpenCV guide and community forum posts
The trust ladder
Each rung states what it proved and what it did not. Gray until proven; green is earned by hardware only.
- generated — A prompt produced it. Unproven — anyone can regenerate this.
- structure-verified — Decode path is structurally sound (addresses, widths, finite values). Does NOT prove word order or scaling.
- interop-verified — Read + decoded cleanly over a real network vs an independent third-party Modbus test server (transport and framing; reads are remapped into the server's register window, so the map's own addresses are NOT exercised). Does NOT prove word order/scaling against the actual device.
- simulator-verified — Decoded correctly against a protocol emulator seeded with known-true values — catches word-order/scaling errors vs the emulator, not the physical device.
- hardware-verified x1 — Matched a real device with operator-attested readings as ground truth — the only rung that confirms word order + scaling on the wire.