Dear Maurice,
Could you please go into details about the function freeze protect.
I want to active this function with a on/off input
Thanks in advance
We put programming for safeties and overrides further down in the program. Lines are evaluated one by one from the top, each successive line below overrides what was done in the earlier lines till the last line is finished after which the outputs are written to the actual hardware.
Therefore we put the freeze protection logic later in the program to override the normal operation logic further up. I like to group all lines related to each output together, so here I have lines 10 thru 30 for the fan and so on. Line 30 for the freeze protection will override the normal operation of the fan which is done in line 20. The damper and valve follow the same pattern with the freeze protection coming after the normal operation logic.
10 REM ***** AIR HANDLER 1 *******
20 IF SCHEDULE THEN START AH1 ELSE STOP AH1
30 IF AH1FRZ THEN STOP AH1
40 REM *** VALVE *****
50 IF AH1STAT THEN VALVE1 = PID1 ELSE VALVE1 = 0
60 IF AH1FRZ THEN VALVE1 = 0
70 REM *** DAMPER *****
80 IF AH1STAT THEN DAMPER1 = PID2 ELSE DAMPER1 = 0
90 IF AH1FRZ THEN DAMPER1 = 0
You could also do the program like below with all the overrides and safeties grouped together at the bottom, but as the logic gets more complex it will be more difficult to follow the logic when its spread out like this.
10 REM ***** AIR HANDLER 1 *******
20 IF SCHEDULE THEN START AH1 ELSE STOP AH1
40 REM *** VALVE *****
50 IF AH1STAT THEN VALVE1 = PID1 ELSE VALVE1 = 0
70 REM *** DAMPER *****
80 IF AH1STAT THEN DAMPER1 = PID2 ELSE DAMPER1 = 0
90 rem *** FREEZE PROTECTION ********
30 IF AH1FRZ THEN STOP AH1
60 IF AH1FRZ THEN VALVE1 = 0
90 IF AH1FRZ THEN DAMPER1 = 0
1 Like
Thanks for your quickly reply.
Just one thing please,
Talking about the tstat8.
Inputs page, last column is function
on the menu second item we have freeze protection
Can someone please provide assistance on this matter
user manual has no info about it, I have tried to look for with no success
We did that a long time back for a client. Will have to dig out what we were doing. Glad to see someone else considering using this.
Maurice Duteau
I am really glad to hearing from you, help is comming soon.
Best Regards