Missing signals or delay in reading them

[pturmel]

See Nick's topic this morning that I just replied to:

Are tagBlocking reads affected by TagGroup updates?

I'm having some issues with synchronising tag reads. The PLC has a number of arrays that store parts information, most importantly the part id. There are 4 arrays, each for different queues the parts are in. These queues have lengths of 50, 20, 20, and 2 parts. Parts move in and out of arrays all the time. I need to read all part ids from these array tags in one hit and combine them together to produce a complete list of parts. I add a column to show each part's location, based on the array. I…

Your simplest solution is to monitor the trigger tag with a tag change event then use system.opc.read*() to get the actual data. Subscribed tags cannot and do not guarantee order of delivery.