OkiePC
Lifetime Supporting Member
BUMP:rephrased:
One more try...
What would cause an extremely high First scan time?
I have a CPU that has always has a 992 to 996 ms first scan time every time it goes to (remote) run mode, and I have studied it closely.
I am still baffled as to why, after finding a First_Scan driven loop in the original code and working it completely out of the code, in addition to massive amounts of logic overhaul, the First scan time remains unchanged.
The SLC 5/04 scans at 25-50 ms all other times. The watchdog is set for 1000ms. It has never "watchdog" timed out in my nine months here! I have seen it hit 996 a few times after amonth of daily checking. Happens every morning on power up, as well as returning to remomte run mode via RSLogix500...every time First_Scan is true, the max reading hits within 8ms of the watchdog, I clear it, and it never again goes above 50 until the next First_Scan.
I suspect it could be I/O or comms related?
There is a pretty heavily populated devicenet control network and around 20 local slots in use. All 30 are enabled.
There are only two nodes on the local DH+ (PV1000 standard, 500ms scan freq. ~300 tags, ~50 alarm bits)
There is also a Net-ENI module connecting it's CH0 to the engineering lab network which could be a factor?
I am at home so I can't post the code...
Tomorrow I may do that...I can't stand a unsolved puzzle!
Any ideas AB experts?
One more try...
What would cause an extremely high First scan time?
I have a CPU that has always has a 992 to 996 ms first scan time every time it goes to (remote) run mode, and I have studied it closely.
I am still baffled as to why, after finding a First_Scan driven loop in the original code and working it completely out of the code, in addition to massive amounts of logic overhaul, the First scan time remains unchanged.
The SLC 5/04 scans at 25-50 ms all other times. The watchdog is set for 1000ms. It has never "watchdog" timed out in my nine months here! I have seen it hit 996 a few times after amonth of daily checking. Happens every morning on power up, as well as returning to remomte run mode via RSLogix500...every time First_Scan is true, the max reading hits within 8ms of the watchdog, I clear it, and it never again goes above 50 until the next First_Scan.
I suspect it could be I/O or comms related?
There is a pretty heavily populated devicenet control network and around 20 local slots in use. All 30 are enabled.
There are only two nodes on the local DH+ (PV1000 standard, 500ms scan freq. ~300 tags, ~50 alarm bits)
There is also a Net-ENI module connecting it's CH0 to the engineering lab network which could be a factor?
I am at home so I can't post the code...
Tomorrow I may do that...I can't stand a unsolved puzzle!
Any ideas AB experts?