All of last year I had to use alligator clips to “switch on” the heating elements in the ETS. Lift off the programmable thermostat and clip them on.
Last week I decided that its time to update the way I get the data from the energy monitor into VTScada, and bought a relay at the same time. Why I didn’t do this any other time in the last 18months is beyond me. While that is in shipping I’ve started the programming in the ClickPLC I have on the wall.
The program modifications
I upgraded the firmware to version 3.20 (it was in the early 2s before) and started digging around to see what information is built in to make this work.
Before I get into the weeds, lets talk about what this little routine needs to do.
We only ever want to “charge” the ETS during the cheap rates. I’m not going to set this up such that it accounts for weekends or holidays differently, it will only account for the nightly rates, from 11pm to 6am. So basically, it will energize an output whenever the time is between 23h and 6h.
I’m writing this after 5pm, or 17h, and that is the value when I check the data view while I’m online.
Now to layout the ladder logic
I plan to use the input X001 as a physical enable with a switch. This will allow me to disable during the non-heating season. I always turn off the ETS itself, but may as well save the cycles on the control relay.
I don’t have the relay, yet, but I can play around to see if its going to work. First, after I load it into the PLC here are the new values. First I need to over ride (OVR) the X001 bit, then lets see how the program runs.
Nothing happens, as expected. It is still 5pm and 17 is bigger than 6 and isn’t 23. Now, what happens when I change 6 -> 20, will it energize the output?
But I still want to test it to make sure that I can get the lights to come on, so I will change the first argument to be 20 instead of 6 and SUCCESS
Now I just need to get the relay and connect everything up.
I had a single relay in the house that I broke before even starting the testing, so I should have a couple new finder relays at my mail box later today, and I will connect it this weekend.
Then when that is working I will re-wire the existing programmable thermostat to control the fan in the ETS to control the temperature in the room.
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