We have a small demo program from a number of years back that originally ran on an LCM4 with a couple B3000 serial brain I/O units. The programming was done in Factory Floor (OptoControl and OptoDisplay) and the system used a single Arcnet connection from the LCM4 controller to the Demo computer running OptoDisplay. In this demo project we have a couple 4 pen real time trend displays showing data from the controller using a 200ms refresh rate. These trends give a nice smooth representation of the data in real time.
We recently updated the hardware to a couple SNAP-PAC-R1s connecting via Ethernet to a newer computer. At the same time we migrated the project to PAC Project Pro (latest version). Once we got it all up and running the trend display on the new system was unacceptable: a very rough line with steps in it that honestly looked horrible. We tried the following things to see if we could get this back to the original system performance with no success:
- Tried different refresh times: this made a difference but no setting came anywhere near close to the original.
- Tried using a super trend with the same refresh time. This was surprisingly somewhat better but it was still a fine, stepped or quantized representation of the data.
- Tried modifying / optimizing our PAC Control strategy using Optoscript and increasing / decreasing time delays in all loops, no change.
- Finally just made a 2 script block test strategy to create four smooth ramped values. Still the same issue.
We have talked to Opto22 support and it appears that there is no solution for this. Before we give up completely, I was hoping that someone on these forums has had experience with running fast trends in real time on PAC Display and figured out a way to make it work. I’m uploading two screen grabs showing the differences in how these display: