In our day and age of computer-controlled appliances, it’s important that we as techs understand how those control boards communicate with each other. This not only deepens our understanding of how appliances work but will also help us troubleshoot appliances with multiple control boards.
Here we have part of a Live Dojo workshop which explains serial data communication between boards. The video takes a look at a microwave-wall oven combo. Don’t even know what serial data communication means? Don’t worry, the video will explain all.
As you learned in the video, serial data communications really aren’t that complicated. In the case of this specific setup, it’s a simple one-wire serial communication. The different boards, such as the UI and main control board, communicate through just one line. The use of handshake protocols means that all boards receive the same data, but only the board who is specifically called out in the handshake will respond to the incoming data.
This is a slow but effective way for boards to communicate. More complicated appliances will have more involved setups, such as using two different data lines, one dedicated solely to transmitting data and the other for receiving data.
The data packets are 5 VDC that is switched on and off at specific rates. Since data is just pulses of 5 VDC, that means you can measure it with your meter. Your meter will average the pulses and show that to you on the screen. If there’s data on that line, you’ll see some average voltage between 1 and 4 VDC. The more pulses, the higher the average reading.
To learn more about troubleshooting and repairing modern, computer-controlled appliances, check out our Core Appliance Repair Training course. Enroll today and begin your journey to Appliance Repair Mastery.