if the t/c o/p is 4-20mv then how plc recognize it
because we are dealing with the 4-20ma in the
plc ????????????????
Answers were Sorted based on User's Feedback
Answer / arindam
why we require a 4-20 mamp for transmission? the main reason
behind it because of electro magnetic interference the
voltage can get interfered very easily and we can't get our
desired o/p value.when we are using 4-20 mamp this problem
is solved but since, PLC is a digital device it can
understand mainly High=5V or low so we design the sink to
have a resistance as high to get the desired voltage, the 4
mamp is also helpful to power the electronics at the
transmitter end. to have a 4-20 mv instead can firstly :
cause em interference and secondly we need to have a
continuous level monitoring for different voltages...which
can increase the size of PLC . Also because of change of
impedance at the transmission line the voltage can drop
below 4 volt ocassionaly then loop powering of field
instrument will not be possible.
Is This Answer Correct ? | 5 Yes | 0 No |
Answer / biswarup das
There is different module in a PLC . Out of which one is T/C
module if you connect the o/p of T/C directly to this module
of PLC , then the PLC will recognise it.
T/C module is not inbuilt we have to select it seperately.
There are many modules like this such as RTD module, 0-10
volt module etc.
Is This Answer Correct ? | 5 Yes | 0 No |
Answer / guest
we will convert mV in to the ma....by connecting resistance
in parallel
Is This Answer Correct ? | 5 Yes | 4 No |
Answer / sreekanth
standard thermocouple output is 0 to 10 mV. There will be 4-
20MA converter either in DCS in the field(Transmitter)as
the modules will accept only 4-20 MA output.
Is This Answer Correct ? | 1 Yes | 5 No |
how to turbine speed measurement?
0 Answers Jindal Steel and Power,
kindly sent some demo question and answer
What is the difference between instrument earthing and normal earthing? and why is it necessary to do so?
what is the meaning if the control valve CV is 27,in terms of selecting procedure?
How to calibrate radar lt type transmitter
what is performance test.need defination
please can any one tell me clearly about pid tuning i am confusing about this .how to tune pid easly?
can we connect instrument earth pit to electrical earth pit, if not why?
How can corrosion alter the accuracy and precision of a C- Bourdon tube pressure gauge?
what is the differnce betweeen hart and smart tx
what is mean of 3 by 2 automation ?
What means zero and span in transmitter callibration.