J
Jasen Betts
- Jan 1, 1970
- 0
Fence post error. You wouldn't be a programmer?
yeah, I was counting posts instead of rails. and yeah, that's my day
job.
Fence post error. You wouldn't be a programmer?
Most of the ones i have seen are 24 volt based. I have seen as little as
12 V and as much as 48 V required.
24 V is very common in industrial control systems, so it is natural to
power the loop from that voltage. With voltage compliance over 20 V
and maximum current up to 20 mA, the total loop resistance can be up
to 1000 ohms, thus quite long wires (kilometers) can be used between
the control room and the sensor in the field, without large
conductors. Minimizing the conductor size is important for cost
reasons as well as keeping the master cable (control room to factory
floor) connecting a large number of sensors at reasonable diameter
(below arm diameter) for easier installation.
-48 V to -60 V are typical telecom voltages, so I guess 48 V
compliance is available mainly in those systems.
I have seldom seen 4-20 mA loops with only 12 V compliance, but
sometimes in 0-20 mA binary Teletype current loop communications.
WoolyBully said:You are so full of shit, boy.
I made Infrared thermometers, and many were 4 to 20 mA Linear output.
That was nearly 25 years ago. I think the two units pointed at Pad 39A
down at Kennedy are of the 4 to 20mA variety. You are a loser.
You're an idiot, still in diapers.
josephkk said:Totally agreed. But data link current loops are not the same as
industrial automation current loops. Part of the discussion is the
differences.
?-)
josephkk said:Most of the ones i have seen are 24 volt based. I have seen as little as
12 V and as much as 48 V required.
?-)
24 V is very common in industrial control systems, so it is natural to
power the loop from that voltage. With voltage compliance over 20 V
and maximum current up to 20 mA, the total loop resistance can be up
to 1000 ohms, thus quite long wires (kilometers) can be used between
the control room and the sensor in the field, without large
conductors. Minimizing the conductor size is important for cost
reasons as well as keeping the master cable (control room to factory
floor) connecting a large number of sensors at reasonable diameter
(below arm diameter) for easier installation.
-48 V to -60 V are typical telecom voltages, so I guess 48 V
compliance is available mainly in those systems.
I have seldom seen 4-20 mA loops with only 12 V compliance, but
sometimes in 0-20 mA binary Teletype current loop communications.
If you did such a thing 25 years ago,
I would of thought by now
you're
language and social skills would have improved?
Your audience much be a bunch of homies
learning new ways to not get
caught the next time.
Were you involved in the design of these thermometers?
WoolyBully said:Absolutely. One of my first engineering positions.
You can FOAD too, little boy. You get nothing further.
What precisely did you design?