The short answer
- Our free player loops files. It does not read a PLC, and it is not a live andon system.
- For live status, run your own Android app or web dashboard on the unit. It has gigabit LAN, RS232 and 12 to 36 V DC power.
- A six-cell board on a 23.8 inch screen shows big digits you can read from about 70 feet. A label 60 pixels tall reads from about 20 feet.
- If you need a board overhead for a whole hall, buy a larger one.
What an andon board is
The Lean Enterprise Institute defines andon as a visual management tool that shows the status of operations in an area at a single glance and signals whenever an abnormality occurs. In practice it can be a stack light, a pull cord, or a board over the line with a cell per station.
The screen is the last and easiest part. The system is what senses a problem, who gets called, and how long they take. Buying a screen does not give you any of that. You still need a signal source: sensors, a PLC, a button, or production software.
Three ways to drive the screen
| Route | Good for | How fresh | What runs it |
|---|---|---|---|
| Files on a card or stick | Shift notices, safety messages, targets for the week | When someone swaps the card | Our free player |
| A picture from your server, with HTTPS sync | Counts and totals that change through the shift | Once a minute at best, plus download time | Our free player, plus a script on your side that writes the image |
| Your own Android app or web dashboard | Live line status and andon calls | As fast as your app and network | Your software, installed instead of the player |
Sync can be set from 1 minute to 7 days. A failed sync is designed to leave the current picture on screen.
The first route is not andon. It is a shop-floor notice board, and that is often all a plant needs at that spot. Our factory page has starter slides for shift notices and PPE reminders.
The second route is a cheap trick worth knowing. A short script on your server draws the current counts into a PNG, updates a small playlist file, and the player picks it up on its next sync. It suits a daily target or a running total. A minute of delay is far too slow for a line stop, so do not use it for that.
The third route is the real one. The unit is an RK3568 Android computer, so a dashboard or an app from your MES or andon vendor can run on it instead of our player. Check with your vendor that their app supports Android, and test it before you buy a batch. We do not supply that software.
How far a board reads
Andon boards are read from further away than menus, so big numbers matter. With six cells on one screen, a digit can take about 40% of its cell's height. Here is how that works out at 30 feet of reading distance per inch of letter height, the road-sign figure we use.
| Size | Nits | Digit height, six cells | Digits read to | Text height at 10 ft | Lines of text at 20 ft |
|---|---|---|---|---|---|
| 15.6 in | 300 | 39 mm | 46 ft | 47 px | 6 |
| 17.3 in | 300 | 43 mm | 51 ft | 42 px | 7 |
| 18.5 in | 400 | 46 mm | 55 ft | 40 px | 8 |
| 21.5 in | 300 | 54 mm | 63 ft | 34 px | 9 |
| 23.8 in | 250 | 60 mm | 70 ft | 31 px | 10 |
So the big number carries across a bay and the small label does not. Design for that: color and digits first, names large or left out. Do not rely on color alone, because some of your staff will not be able to tell red from green. A word like STOP does the job.
The 18.5 inch has the brightest standard panel, at 400 nits. The 23.8 inch is 250 nits. Under strong high-bay lighting, that difference may matter more than the extra size. Try it in the bay before you buy a batch.
Power and the plant
Many control cabinets already have a 24 V DC rail. These units take 12 to 36 V DC at 18 W static, about 0.75 A at 24 V, so a screen beside a cabinet can share that feed if your electrician is happy with the load. Allow 36 W per unit when you size a supply. Details are in the power guide.
Every size is rated -10 to 60 °C and 95% non-condensing humidity, with IP65 on the front face only. The rear of the unit is not sealed. Recessing it in a panel can shelter the rear, but that depends on the panel. See the cut-out guide.
Where this is the wrong choice
- You want a complete andon system. Buy one from an andon vendor. We sell the screen only.
- A board for a whole hall. The largest screen here is 23.8 inches. Overhead boards read across a long bay are usually far larger.
- Anything safety-related. A status screen is not a safety device. Keep stack lights, e-stops and alarms as they are, and do not route them through the sign.
- Washdown areas. IP65 covers the front face only, so this is not a washdown unit.
- Direct PLC tie-in with no software. The unit does not read a PLC by itself. Your app has to do it.
Questions
What is an andon board?
A display that shows the status of production at a glance and signals when something goes wrong, usually with one cell per line or station.
Can our free player run a live andon board?
No. It loops images and video from a card or from your own server. For live status, install your own Android app or web dashboard on the unit.
How do I connect a screen to my PLC?
Through software. These units have gigabit LAN and one RS232 port, but they do not read a PLC by themselves. An app or dashboard from your MES or andon vendor does that part.
How far away can you read an andon board?
It depends on the digit height. On a 23.8 inch screen with six cells, digits are about 60 mm tall, which reads from about 70 feet at 30 feet per inch. Use larger cells for longer distances.
Planning information, not legal or engineering advice. Rules differ by place: check codes and permits with your local authority and your licensed trades.