PAC Display Data Log Trigger


#1

I have a question regarding the historical data log trigger. I have a trigger based on temperature. When the temperature is greater than 200 degrees C on the ramp to 760 degrees C, data is collected. On cool down, when TC26 is less than 100 degrees C, data collection stops. This all works well unless there is a problem with the HMI computer. If we reboot the HMI computer, the data is no longer collected. Even if I used a digital trigger to go true when greater than 200 and I have the digital trigger set to be 0 on Snap-Pac start up, this would not help if only the HMI were restarted and not the Snap-Pac.
If the HMI is rebooted, I would like the data to be appended to the last file if TC26 >= 200. I could live with a little less data, it does not have to be 100 on cool down. It could be collect data anytime that TC26 >=200.


#2

You could do this by performing the temperature check in your strategy and setting a flag variable to trigger the log (just one log entry) - you can set the historical logging to clear this flag under the notification section (I think that is what it is called…). You would perform the check in your strategy as often as you needed the log entry to be performed.


#3

This logs for about 10 days every minute. I just wish there was a way to do this without continuously triggering the data log for 10 days. It works great unless there is a computer problem that requires a restart.


#4

You could have the PAC Controller monitor the computer and only set the variable if the computer goes down/comes back up…
The controller can ping the IP address of the computer. Not fool proof, but might be simple enough to do the job for you.

For a more complex method of checking if the HMI PC is up and running, look at this thread here;


#5

What is wrong with triggering it to log once a minute? It’s a machine, it really won’t mind the work. It also allows you to set a configurable setpoint on your logging temperature if you ever needed it.