Weird Perspective Label String Data

Ignition
1

Good Day,

I have a perspective project and am simply displaying a string in a label component. The string is coming from a Sparkplug B MQTT message via my MQTT broker, originating from a Canary Data Historian. The string is there but there are block characters between each character. Please help get rid of them!! Thank you in advance!

image
image919×671 94.8 KB

2

It looks like a Unicode problem (> 1 byte per character). Show us your text property binding (nicely formatted as code - see Wiki - how to post code on this forum).

3

Hey Transistor,

Thank you for the quick reply. There is no property binding just a direct tag binding therefore there is no code to attach.

Tim

4

I'm struggling to recreate the problem.

Try adding an expression transform to your binding:
urlEncode({value})
This will show the HTTP encoding for any odd characters. (The space character, for example, is encoded as %20.)
Paste the results in here.

A list of values here: HTML URL Encoding Reference.

5

can you run this in your script console and post the results here?

actualData = system.tag.readBlocking(['Path/to/suspect/tag'])[0].value

expectedString = "PREAHEAT"

print "Expected: ",expectedString
print "Actual: ",actualData
print "\r\n"

for i in range(len(actualData)):
    expChar = expectedString[i:i+1]
    actChar = actualData[i:i+1]
    print "Expected: " , expChar, " Ord: ", ord(expChar) if expChar != ""
    print "Actual: ", actChar, " Ord: ", ord(actChar) if actChar != ""
6

Expected Test: PREHEAT

Resulted of urlEncode:
image

7

It seems your string has null bytes preceding each character... you should really try to fix this at the source, but you might be able to use the replace expression function to replace the null's with "" (empty string).

2 Likes
8

That's what I expected you would find and Kevin's solution was going to be my next suggestion.
Try replacing the urlEncode transform with the expression,
replace({value}, char(0), "")

(Since I haven't been able to create the problem this solution is untested.)