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Ren-W Controller Heater
- In some very cold situations (below freezing), you may encounter a problem whereby a controller may function fine above freezing, but when the temperature drops below freezing, or even below zero, the controller ceases to respond. The problem is that either the Ren-W cannot "lock in" and capture a signal, which of course creates a communication problem or the temperature is outside the manufacturer's specs for proper operation. For example, the XBee radio is rated to -40C, which is pretty cold. But the MAX232 chip that Ren-W uses comes in multiple kinds, and the operating temperature specifications can vary widely. If the MAX232 ceases to function, communication to the controller cannot occur.
- Likewise, it's possible that components on the controller itself may cease to function when the environment is outside the operating temperatures of the components. The chips that control RS-485 communication, or the H11AA1 optocoupler, or perhaps even a PIC might not like very cold temperatures.
- The solution is simple: install a small heater bulb inside the controller box. The steps below outline one solution that is proven to work.
- Parts and Tools Needed
- Candelabra socket with a mounting hicket/lug. Example: Servalite CS-10014-52U. (Lowe's, about $2.75)
- 15watt, 120vac tubular light bulb with candelabra mount. (Lowe's, 2 for approx $3.00) These are quite small, about 2" long and 1/2 inch across.
- Length of SPT-1 or SPT-2 cord
- A/C plug
- TOOLS: drill, screwdriver, pliers, zip ties,