Lighting Control

[dcorby 0]

I am trying to set up a lighting control circuit with 7 programmable events in a Logix 5000 system. The problem that I am having is this. If the power goes out when the timed event occurs, there is no easy way to make certain that the event actually occurs. As an example, if event one should turn on at 9:00 PM on Sunday evening, and turn off at 2:00 AM on Tuesday. Then we might have another event that turns on at 9:00 PM on Tuesday and then off at 2:00 AM on Saturday. I was trying to avoid latches if at all possible. We are using a PanelView Plus as an OI. Thanks!!

[ssommers 20]

I haven't done something like this before, but I know there's a real-time clock in Logix5000 so it should be possible to do a compare to turn something on between time X & Y. That would allow you to return to a normal state after a power failure or planned outage. The key may be calculating what day is today - Sunday or Tuesday. There's a formula for that somewhere... Are you planning to use the screen to allow an operator to adjust the event times? Good luck!

[dcorby 0]

Yes, we have a touch screen with 7 events that you set a day, hour and minute for the on and off time. The trouble I am having is how to come up with the logic to be able to turn it on and off. It is actually very similiar to the type of lighting controls that you purchase, but they are so spread out that it takes several hours each tie we need to change them for schedule adjustments, daylight savings time, etc. We are trying to incorporate this into our building automation system. My only proiblem is in coming up with the logic as to how to turn it on and off, the rest is pretty straightforward.

[protiusmime 0]

In the CTX family, you could use your GSV and a 7element DINT (date[0-6]) to store the year, month, day, hour, minute, and seconds. Using these elements a simple logical EQU string on a rung could condition each On/OFF time for your controls. e.g.: date[0] = year date[1] = month date[2] = day date[3] = hour date[4] = minute date[5] = second Such that if date[2] = 1, and date[3] = 10, and date[4] = 30, then turn on OTEx. OTE is true on Monday at 10:30. You would use military time so to avoid the 12-hour conflicts. You would want to increment your day counter by using the same idea to ADD 1 to a seperate tag addy (e.g. DAY_OF_WEEK) and when becomes >7, you would MOV a 1 back into the address to start over on Monday (1). EQU(date[5],59)EQU(date[4],50)EQU(date[3],5)ONS(ONS_LIGHT1_ON)OTE(LIGHT_ON); GRT(DAY_OF_WEEK,7)MOV(1,DAY_OF_WEEK); MOV(DAY_OF_WEEK,TODAY[0]); And the same for your OFF time, with comparators above set for your day,hour,minute off time. = OTE(LIGHT_OFF) Check it out and see if this makes sense.