When updating the numeric text field (tag for the field is bound to an OPC tag), if I enter 18.073 and it then updates the tag. Once the tag is updated, it will then add a ton of decimal place values to the value after the 0.073.
I think it may be some type of data conversion when communicating through the OPC server, however, the PLC is never writing back to the OPC server. The user input from Ignition is all that is being sent to the numeric text field.
What type of PLC is this, out of curiosity? I think I’ve seen this behavior before w/ ControlLogix in particular.
CompactLogix, so close.
I’m not sure what I could change. I’ll test it on a memory tag to see if it happens on that too? Likely it’s only OPC tags, I would assume.
lautry,
I tried to setup the same on my end and you are right, the Value(Double) and Value(Float) show 18.072999954 but the good news is both on the OPC tag and in the PLC i see 18.073 so technically you shouldn’t have any issues as far as the wrong value being sent to the PLC.
Now as far as the second part of your post, what you mean PLC is never writing back to the OPC server? are you talking about when changing the value in the PLC the OPC tag never changes?
I just tested mine, I changed the value on Ignition and it changed it in the PLC and then changed the value to 17.473 in the PLC and i saw it changing the tag value in Ignition and also the text field.
Did you bind the float property to the PLC tag and select bidirectional? That should be all you need to do for this to work without any issues.
let me know if that solved your issue.
So, I meant that nothing is overwriting the tag value on Ignition. It’s purely controlled via the vision component, and not some external value from the PLC.
So, it seems you also think it doesn’t affect the actual value? Maybe it’s just a display issue?
I did that test just to confirm if it’s going to effect the value and it didn’t. I think however the float and double values get converted ends up making them displayed with those digits. You should be fine as far as data value being correct. The only place those extra numbers are displayed is in the property section of the component as far as I can see so you should be fine.
Hello Everyone,
I am having trouble with the numeric text field. When I write a value to an OPC tag, it sends it to my destination which is the SEL RTAC device. Once the value gets written to the destination, the OPC tag changes its value to 0. I want the OPC tag to retain the value. I have enabled the bidirectional feature. However, it is of no help.
Your inputs would be of great help.
Thanks