Opto22 controller questions Aug 1, 2002 9:46 am, by Chris Pepmeier Subject : PLCs from the engineering dept. Text : Question #1: How will increasing the "Host Task Priority" of Port 4 to 10 affect the execution of the charts within my strategy? I am trying to improve the update time from the Opto22 controller to my HMI application. I am using Intouch by Wonderware as my HMI and Mistc200 by Standard Automation as the I/O server. I was experiencing update times of approximately 7.5 seconds. I increased the "Host Task Priority" of Port 4 to 10, and my update time dropped to 2.5 seconds. I am curious how this will affect the performance of my charts. Question #2: Is there a recommended maximum time percentage the Acrnet port should be active? After increasing the Host Task Priority of Port 4 to 10, I have noticed that the Arcnet LED is almost solid ON. Question #3: What is the "Comm. Loop Time" actually measuring? I have observed that this time increases dramatically when I connect my HMI application to the Opto22 controller. With the Host Task priority of Port 4 set at 1, the Comm. Loop Time is approximately 800 ms when when communicating with the HMI. With the Host Task Priority of Port 4 set at 10, the Comm. Loop Time is approximately 300 ms when when communicating with the HMI. When not communicating with the HMI, the Comm. Loop Time is less than 100 ms. Is there any significance in these numbers？ Thank you in advance for any information that you can provide me. Sincerely, Chris Pepmeier Reply -------------------------------------------------------------------------------- Re: Opto22 controller questions Aug 7, 2002 10:45 am, by Bill Steffens Hi Chris, Opto 22 offers free technical support and has answers for your questions. I recommend you redirect your question to the Opto 22 Product Support Group at: E-mail: support@opto22.com Phone (toll free): 800-835-6786 Phone (direct): 909-695-3080 Sincerely, Opto 22 Product Support Reply Re: Opto22 controller questions Jan 2, 2003 2:45 pm, by DarthVader 1. An opto controller divides everything into 32 time slices,one slice goes to each chart, and one goes to the host task (generally a MMI). If there are less than 32 things, then it just starts it is process over again after the last task. Increasing the host task priority gives the MMI an extra slice of time, or in your case 10 slices of time. This will slow down your other charts, but they may still be fast enough to work properly. It is a trade off. 2. The ARCNET port is more active, because you are giving more processing time to the MMI. If everything is working properly, then this is nothing to worry about. 3. The comm loop time is similar to the ping time of somethign on ethernet. The PC sends a signal to the processor, and the processor sends a signal back. The time it takes the PC to get that signal back is the comm loop time. This is essentially the speed of the connection between the processor and the PC. The comm loop time is faster when it is not talking to the MMI because the HMI isnot taking any of the connection speed. Reply