Originally written and posted 2 June 2001.
Content last modified Friday, 8 June 2018 .
External links last verified Friday, 8 June 2016.

CP290 home control interface

CP290 Home Automation Interface

There has been a great deal written about the CP290, including modifications to improve clock timekeeping and the like. It used to be possible to visit the Home Automation Knowledge Base (Dead Link, remaining here in case it gets revived, and for archive searching) and ferret around there for most, if not all, of this useful information compiled by fellow X-10ers. Sadly, with the demise of that site, you’ll have to do your own searching. Having nothing else new to add to the CP290 saga, i shall restrict myself here to the alignment procedure.

CP290 Alignment

To ensure successful alignment, please be sure to read important information common to all X-10 alignment procedures before proceeding.

CPU Frequency Adjustment

I do not know what effect this would have on any external function, therefore i found no reason to adjust TC3, and left it as-shipped from the factory.

PLC Frequency Adjustment

  1. Unplug CP290 and remove the 3 under-foot screws and the one in the battery compartment holding the two body halves together.
  2. Position the unit in a fashion which allows easy adjustment of the two transformers which will be adjusted.
  3. Connect frequency counter to powerline signal sensor (not CP290). Power up counter and signal sensor, allow counter to stabilize.
  4. Short transistor TR5 base to emitter to allow the 120kHz oscillator to free-run.
  5. Connect CP290 to A.C. line.
  6. Adjust transformer TC2 for 120kHz.
  7. Unplug the CP290, powerline signal sensor, and disconnect the frequency counter. Leave the free-run short circuit in place.

PLC Output Amplitude Adjustment

  1. Move the CP290 to the location where it will be used. Bring along oscilloscope and powerline signal sensor; connect these to a separate circuit, or at least an electrically distant outlet on the same circuit.
  2. Set up oscilloscope and powerline signal sensor to monitor the A.C. line.
  3. Connect CP290 directly to the A.C. line.
  4. Adjust transformer TC1 for maximum 120kHz signal amplitude. This is likely to be a broad, “low-Q” peak.
  5. Unplug/disconnect all. Remove the B-E short on TR5.
  6. Connect CP290 to computer and A.C. line. Run self-test. Reload programming. Test for normal operation.
  7. Unplug and reassemble CP290.
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