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Old 05-14-13, 01:48 PM   #9
AC_Hacker
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Default The Inscrutable Thermostat Menu

I worked on the thermostat this morning, the menu in particular, and I found that there were actually some aspects where the where the Chinese 'manual' and the downloaded 'manual' and the menu in the device that displays on the front of the thermostat, actually agree... but then sometimes not so much.

So here is what I found out...

This is a typical display, there are two LEDs that may or may not be lit, depending on their status on the left side of the display. Right now the display is showing the temperature and neither of the status LEDs are on.


The upper LED, 'WORK' comes on whenever the internal relay is active and off when the relay is inactive.


The lower LED, 'SET' comes on whenever the 'SET' mode is active, and goes off whenever the set mode is not active.


To set the temperature to the trigger point at which you want the thermostat to turn on (or off, depending on whether you want to use this device to control cooling or heating) you push the 'SET' control once and use the up and down arrows to set the 'trigger point'. The display will return to the usual display in a few seconds after sensing no activity from the buttons.


To enter 'MENU' mode, press the 'SET' button and hold for 3 or more seconds.


I found 6 menu items, and they were: HC, P7, CA, H5, L5, and d.


This is the 'HC' menu item. press 'SET' again and you will enter the HC menu, where you will be able to choose 'HC' (for chill) or 'HH' (for heat). HC will allow you to use the thermostat for a cooling device (turning on a cooler if the target temperature is exceeded). Likewise, HH will allow you to use the thermostat for a heating device (turning on a heater if the target temperature is too low).


This is the 'P7' menu item. It is supposed to be understood as 'PT'. The range of values available was 0 through 10.


This is the 'CA' menu item and it is used for calibration. You can use this to shift the displayed temperature to agree with the actual temperature. I found I needed to use this. The thermistor was accurate at room temperature, but at refrigerator temperature, it was off by 3 degrees C or more. I was able to adjust the displayed temp to very accurately agree with a more reliable thermometer.


This is the 'H5' menu item. It is supposed to be understood as 'HS'. The range is large. With this menu item, you can adjust the upper temperature range. Possibly this can be used for an alarm?


This is the 'L5' menu item. It is supposed to be understood as 'LS'. The range is large. With this menu item, you can adjust the lower temperature range. Possibly this can be used for an alarm?


This is the 'd' menu item. It is used to adjust the hysteresis of the system. Perhaps the 'd' means 'deviation', and so allows the user to set the deviation range before the thermostat triggers, thus preventing short cycling.

[NOTE: Both the Chinese instruction manual that came with the thermostat unit and the English on-line manual indicated that there were more choices available in the menu, specifically choices for setting alarms (which could be very useful), that did not appear in the menu of the unit I received. Possibly terminals #5 & #6 that have Chinese descriptors are for an alarm.]


This is what I have uncovered so far... not yet complete.

I am still running the Freezerator with the old Teensy thermostat, and I have the WH7016 running in parallel, monitoring its readout and the status of the output relay.

When they are pretty close to equivalent, I'll switch over.

Best,

-AC
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Last edited by AC_Hacker; 05-14-13 at 06:00 PM..
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