G
We just finished a PLC upgrade from 984 processors to Quantum Unity processors. We did a conversion, not a re-write, so 90+% of the logic is still in 984LL.
What it appears is the following:
1. The 984LL conversion is overwhelming the Unity Pro and we are getting slow scan times, over 90ms.
2. The slow scan times are causing the totalizers to be far off. Initially we were using .6s clocking and they were way off, then moved to 6s and they are 4+% off.
3. We have tried both the IEC totalizers built into Unity and we tried our own custom built totalizers with better success, but still not accurate.
4. When we called Schneider, they said if this was really a problem, their phones would be ringing off the hook about it, so it must not be a problem. I really have an issue with that stance.
5. How do we know what it should be? We basically are also recording through SCADA and using those values and an average to verify the daily total. We would prefer to use the PLC for totalizing, but we will use the SCADA system if there is not alternative.
Questions:
1. Has anyone noticed this issue of Schneider IEC totalizing being incorrect?
2. Has anyone had speed problems with Unity conversions that contain a large percentage of 984LL?
3. Are there any other thoughts?
GBrown
What it appears is the following:
1. The 984LL conversion is overwhelming the Unity Pro and we are getting slow scan times, over 90ms.
2. The slow scan times are causing the totalizers to be far off. Initially we were using .6s clocking and they were way off, then moved to 6s and they are 4+% off.
3. We have tried both the IEC totalizers built into Unity and we tried our own custom built totalizers with better success, but still not accurate.
4. When we called Schneider, they said if this was really a problem, their phones would be ringing off the hook about it, so it must not be a problem. I really have an issue with that stance.
5. How do we know what it should be? We basically are also recording through SCADA and using those values and an average to verify the daily total. We would prefer to use the PLC for totalizing, but we will use the SCADA system if there is not alternative.
Questions:
1. Has anyone noticed this issue of Schneider IEC totalizing being incorrect?
2. Has anyone had speed problems with Unity conversions that contain a large percentage of 984LL?
3. Are there any other thoughts?
GBrown