572 tags and storage / events

Hey All,

I have a furnace which takes in 572 tags of operator controlled data from the HMI. The glass stages on the load conveyor and every 30 seconds or longer it gets called into the furnace with an index tag. I am using that tags value changed event to fire a trigger script. In the trigger script I am setting a memory tag to the value of 1 then setting it back to 0. The memory tag is called record_x and it is incremented each time it is called and resets back to 0 once it reaches 9.

Inside the record_x script I am opening a file, looping through the tags and values and writing them to the file_x then closing the file pulling another file from a different machine and adding both files to a main storage file. The other machine gives me the curvature / quality of the glass. So I like to keep the beds separated and that file attached to the bottom of the tag value / record_x code results.

The issue I am having is after 3 record_x scripts trigger and running on top of each other my ignition server practically shuts down. I am running a dual core 2.5 ghz 8gb ram CPU and I believe this is where my problem lies. If I don’t bog the system down the coding performs flawlessly, but all of this entire operation may be inefficient. Looking for wisdom / please enlighten me.

Below is my recording_x script:

# only execute when triggered
if (currentValue.value == 1):

	# import required libraries
	import os
	import time
	import sys
	# Initialize Some Used Variables
	heat_quench_time = system.tag.read("[.]Heat_Quench_Time").value
	max_file_size = system.tag.read("[.]Max_File_Size_Ctr").value
	total_time_divided = heat_quench_time / 2
	file_name_ctr = system.tag.read("[.]File_Name_Ctr").value
	tag_names = (["572 tags"])
	tag_values = []
	tag_name_ctr = 0
	file_open = open("C:\\GlassTech_Recording\\Temporary_Recordings\\Temp_Storage" + str(file_name_ctr) + ".txt", 'w')
	# for range of total divided sleep 1 and write every second
	for sec in range(total_time_divided):
		# while inside total time divided loop
		# loop through all of tag_read_all_values and write to file_open
		for tag_value in tag_read_all_values:
			tag_values = tag_value.value
			file_open.write("%s = %s\n" % (tag_names[tag_name_ctr], tag_values))
			tag_name_ctr += 1
			# inside of nested for loop check ctr
			if (tag_name_ctr >= 573):
				tag_name_ctr = 0
	tag_name_ctr = 0

You are using sleep(). If you need to do something on one-second intervals, use a one-second timer event. Tag events run from a thread pool, and your sleeping threads are blocking the pool.

The only place sleep() is safe (and is usually unwise there, too) is in an asynchronous background thread.


+1 to Phil’s statement.

Also, reading 572 tags in a loop is very inefficient. You should read all tags at once. You didn’t mention the version of Ignition you’re using (always helpful to know), but assuming v8:

tag_names = ["572 tags"]
tag_q_values = system.tag.readBlocking(tag_names)

file_open = open("C:\\GlassTech_Recording\\Temporary_Recordings\\Temp_Storage" + str(file_name_ctr) + ".txt", 'w')

for tagName, qValue in zip(tag_names, tag_q_values):
	file_open.write("%s = %s\n" % (tagName, str(qValue.value))

That aside, this is an application that, IMO, should be writing values to a database. Specifically, this is what the SQL Bridge was made for.


Gentlemen, I appreciate the information and will revise as recommended. I can throw it to the SQL database as well. Regards.