Andon systems
Andon boards driven by your PLC.
An andon board tells the floor what is happening at each station. Most installations use stack lights — three colours and no numbers. A matrix display shows the value itself: output, target, alarm code, downtime reason.
What the board shows
The content is whatever your PLC holds in its registers. Typical andon content:
Station status
Running, idle, changeover, fault. Often colour-coded across the whole panel.
Call for help
Operator requests assistance or material. The station number appears with the state.
Count & target
Current output against the shift target, updated as the counter increments.
Alarm code
The fault number from the PLC, shown where the operator can read it from the aisle.
Matrix display or stack light
| Stack light | LED matrix display | |
|---|---|---|
| Shows | One of three colours | Numbers, text, codes |
| Operator has to guess | What the fault is | Nothing — the code is on the board |
| Wiring | Discrete outputs per colour | Two wires, RS-485 |
| Change what it shows | Re-wire the outputs | Change the register mapping |
| Distance from panel | Anywhere the cable reaches | Anywhere the RS-485 bus reaches |
Many plants keep the stack light for the colour and add a matrix panel for the detail. Both can hang off the same PLC.
Three ways to connect
Pick based on what you are allowed to change in the PLC program.
Master
The panel reads the PLC.
No PLC program change. Requires the PLC to expose a Modbus slave interface, which most do.
Slave
The PLC writes to the panel.
Full control over what is shown, when. Requires development on the PLC side.
Listen-onlyOUR EDGE
Nobody changes anything.
The panel taps the existing RS-485 bus in parallel. Read-only, no transmission, no interference with the PLC program. For plants where the program must not be touched.
Choosing a size
Two things decide the panel: how many characters per line, and how many lines.
| Content | Typical panel | Reason |
|---|---|---|
| Station number + status | 35 × 19 cm, 2 lines | 8 characters per line is enough for "ST-04 RUN" |
| Count / target | 65 × 19 cm, 2 lines | 16 characters covers "1240 / 1500" with a label |
| Multi-station summary | 95 × 35 cm, 4 lines | Four stations stacked, readable from the aisle |
| Line-end summary | 125 × 19 cm, 2 lines | 32 characters across, read from the far end |
All indoor models use 16-dot characters at P4.75 pitch. Full model list on the main page.
What you need to tell us
A quotation needs four things: the PLC model, the registers that hold the values, how many panels, and the distance from the panel to the PLC.
Request a quotation