ANSI/ISA-5.1-2009 clears it up.
For a multivariable scan device it would be:
UJ-xxxx
UJI-xxxx.
For a single variable 'smart' scanned device it would be:
TJ-xxxx
TJI-xxxx
IF the same single variable 'smart' device used the 4-20mA signal to transmit the variable it would be the normal:
TT-xxxx...
It does matter. I agree, consistency is key. However, when you 'bid' out jobs, unless there is a standard to follow, you will have differences with installations. If 90% of what a technician works on, Black is negative and someone installs a few that have White as negative, problems will happen...
Ok; Ok. Good discussion! Now, if we can get everyone else on board with 'UT' or 'UIT'...
I agree with the label next to the data link cable. I guess by my wanting the signal type in the tag name has more to do with my frustration over people not understanding the instruments. No, the signal...
Ok, let's address the loop function. You have an FE-301; everything on the flow process 'loop' that is associated with FE-301 will be referenced to '-301', the number of the 'loop'.
FT-301, PT-301, TT-301, and yes, even PDT-301 (I keep wanting to write 'DP'!).
JL, I appreciate the feedback; good comments. If it does do internal flow totalization then I agree with you on the quantity use and Q could, and probably should be used.
Simpler is better, but with a complex device, the alpha prefix almost needs to be 4 characters to try and convey the...
When I worked in an older plant they had differential pressure transmitters that had square root mA outputs representing flow. Similar to what you mentioned, they used a simple meter display scaled for 0-100% for square root and read the percentage of flow DIRECTLY, no conversion, no calculator...
Hello, in another forum I posted thread196-248328. I believe a discussion is also need here.
John wrote that "It is common for 24 VDC 4-20 mA loops to use black and white pairs, typically with 24 VDC source on the black wire. Black and red is also used.
I would like to say that in over 27...
thread196-100316
John wrote that "It is common for 24 VDC 4-20 mA loops to use black and white pairs, typically with 24 VDC source on the black wire. Black and red is also used.
I would like to say that in over 27 years it has only been over the last few years that people have tried to promote...
thread196-122680
Hello, I would like to point out that unless a differential pressure transmitter has a square-root output, it should not be designated as ‘FT’, it should be 'PDT'. I know, 'FT' is still widely used with a linear output, but that doesn’t make it correct…
What do you think?
Mike
I’ve yet to see a logical multiple function device (MV) transmitter identification written anywhere. I propose the following for transmitters NOT doing flow calculations:
UT-xxxx for a MV utilizing HART communications.
UIT-xxxx for a MVT utilizing HART communications with a LCD readout...
