I_Automation
Lifetime Supporting Member
I was online a SLC5/04 yesterday and one thing I did was go to processor properties and set the date and time to get the PLC clock current. It wasn't off a lot, but a good time to get it exact.
When I clicked the button I noticed the outputs that were enabled by clock time all flickered off quickly. Did it again and they flickered again.
When I got home I wanted to see what was going on so in my home automation SLC5/05 I set a few traps and logs.
Turns out when the time is set online the time goes to 00:00:00 for about 0.04 seconds and during that time since it's midnight officially the clock controlled outputs turn off or on as they should be at midnight.
I say about 0.04 because a couple of times it logged 0.03 seconds, but mostly 0.04 so if I put a 0.001 time base I'm guessing it's somewhere around 0.035
After the 0.04 seconds of midnight the clock then reads the new time.
EDIT: If you change the time by the program or entering a new value in the S2 file when online it jumps to the new time immediately, not even 1 scan of 00:00:00
Been working on SLC's since the 90's and never noticed this before yesterday.
EDIT 2: Now I'm wondering if the time is externally set by a message or time synch master if it does this. I don't have another 5/05 to test this with so I'll just keep it on my ToDo list.
When I clicked the button I noticed the outputs that were enabled by clock time all flickered off quickly. Did it again and they flickered again.
When I got home I wanted to see what was going on so in my home automation SLC5/05 I set a few traps and logs.
Turns out when the time is set online the time goes to 00:00:00 for about 0.04 seconds and during that time since it's midnight officially the clock controlled outputs turn off or on as they should be at midnight.
I say about 0.04 because a couple of times it logged 0.03 seconds, but mostly 0.04 so if I put a 0.001 time base I'm guessing it's somewhere around 0.035
After the 0.04 seconds of midnight the clock then reads the new time.
EDIT: If you change the time by the program or entering a new value in the S2 file when online it jumps to the new time immediately, not even 1 scan of 00:00:00
Been working on SLC's since the 90's and never noticed this before yesterday.
EDIT 2: Now I'm wondering if the time is externally set by a message or time synch master if it does this. I don't have another 5/05 to test this with so I'll just keep it on my ToDo list.
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