Troubleshooting
We like to start troubleshooting problems by thinking about what might plausibly go wrong. X-10 networks are simple enough in operation that there are only a few options:
No signal reached the power line — The transmitter might be defective, or the transmitter might be disconnected from the power line.
Unreliable wireless operation — The X-10 motion detectors are the most common wireless transmitters; if their signal isn’t received, the system will behave as if the sensor isn’t working. Poor wireless signal reception can be caused by weak batteries, competing radio signals acting as noise and jamming the signal, blockage between transmitter and receiver, or excessive range between transmitter and receiver.
No signal, a weak signal, or a noisy signal reached the receiver — There might be filters or other losses on the power line, the signal might not be coupling into the other side of the power panel adequately, or noise signals might be corrupting the incoming signal. Noise sources include contention between multiple X-10 transmitters operating at the same time.
The receiver isn’t responding — The receiver might be broken, might not be properly connected to the power line, might be receiving on an address different than the transmitter is sending, might not respond to an unusual command sequence being sent, or might be connected to a load that doesn’t work.
Figure 15 shows that problems can afflict every part of the network, but because of the serial nature of the connections, shows that you can troubleshoot by starting at one end and following the signal (or its absence). You can start at either the controller or the load.
FIGURE 15: X-10 network faults
If you start at the load, your sequence might follow this sequence:
1. If there’s a manual switch at the receiver, see whether it will turn the load on or off. If not, substitute another receiver temporarily and see whether it controls the load where the proper one will not.
2. Assuming the receiver can control the load, try isolating the receiver and a known good test transmitter on a power line isolated by a filter from the rest of the house, and see whether the transmitter will control the receiver. If not, check the addressing and connections, and perhaps replace the receiver.
3. The receiver working in isolation suggests that either the problem is external to the isolated segment or the receiver is not as sensitive as it needs to be. Use a signal strength meter, such as the combination of the X-10 Pro XPTT transmitter and XPTR receiver, respectively. The XPTT sends a continuous signal turning address P1 on and off; the XPTR measures the strength of the received signal for P1. If you connect the XPTT at the location of your transmitter and the XPTR at the receiver, you can measure the signal transported by the power line between the two sites. You need 200 mV (millivolts) by specification, but if the signal is that low you’ll need a very clean, noise-free system.
If the problem is noise, you’ll need to try to identify the source. Don’t just turn units off, unplug them — many electronic designs don’t really turn off even when they look off, and noise or loading from the power supply won’t vanish unless you disconnect the power supply from the power line. Should you find a significant noise source, use a filter or noise blocker to clean up the pollution.
4. Use a known good receiver in an isolated segment against the transmitter, and try a test transmitter instead of the real transmitter.
5. Finally, although unlikely, erratic operation could be caused by signals fed in through the power transformer from a neighboring house. Use the XPTR to look for signals on the line when nothing should be happening.
It’s not too likely you’d see unreliable operation from network collisions unless you’re operating specialized equipment such as drapery or blind controls, but you can use the XPTR to see traffic loads. Figure 16 shows the X-10 Pro XPTT and XPTR units. There are no controls on the XPTT; the single LED on the faceplate flashes when the device is in operation.
FIGURE 16: X-10 Pro XPTT (left) and XPTR (right)
The XPTR faceplate is organized into columns. The left column has LEDs to indicate a reception error or one of four signal levels; the right column has the Hi/Low Range button and the Reset button. Pushing Hi/Low Range sets the LEDs to indicate 250 mV to 2 V; releasing it selects the 25 to 200 mV range. There are no other controls — you just plug them into the outlets you want to test.