Where to Configure Tag Update Frequency (Scan Rate) and Use Scan Groups in Ignition 8.3?

Ignition
1

Hello everyone,

I am working with Ignition 8.3 and am having trouble properly configuring the tag update frequency, especially for Modbus tags. In previous versions, I was able to configure the Scan Class to set the update frequency for tags, but I cannot find this option in Ignition 8.3.

Here are my questions:

  1. In Ignition 8.3, where can I configure the update frequency (Scan Rate) for tags (especially Modbus tags)?

  2. Should I use Scan Groups to manage the tag frequency, and if so, how do I correctly associate a tag with a Scan Group?

  3. Where exactly is the frequency property located in the Ignition 8.3 interface? I’ve looked through the tag properties and Scan Groups, but I can’t find the exact location.

  4. Are there any resources or practical examples for configuring Scan Groups and tag update frequencies in Ignition 8.3?

Thank you in advance for your help!

2

You’re looking for “Tag Groups” and the Rate property.

3

Hello,

Thank you for sharing the documentation; it was really helpful!

I’ve configured the Scan Rate (Rate) for my tags in Ignition to 200 ms, but my equipment actually has an acquisition time of 300 ms instead of 200 ms. The protocol used for data acquisition is Modbus TCP/IP.

My question is:

  1. Can adjusting the Rate for all tags to match the equipment’s acquisition time improve data acquisition when handling large volumes of data?

  2. Are there any performance concerns when setting a fast scan rate (e.g., 200 ms) for multiple tags if the equipment requires a longer acquisition time (300 ms)?

  3. Is there a recommended strategy for configuring the Rate when collecting large datasets, considering the equipment’s acquisition time?

4

  1. Yes. Attempting to poll faster than the device is internally generating values is pointless and hurts performance.

  2. Yes. Attempting to poll faster than the device is internally generating values is pointless and hurts performance.

  3. Yes. Poll slower or fewer. Attempting to poll faster than the device is internally generating values is pointless and hurts performance.

  4. (You didn't ask a fourth question, but...) Attempting to poll faster than the device can respond and deliver the values is pointless and hurts (write) performance.

#4 is the bottleneck for most devices.

There's no magic wand in Ignition if the device is the limiting factor.