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A.4 Setting Range Values (Local Zero and Span), Continued
Procedure, continued
Table A-3 Setting Range Values Using Local Zero and Span
Adjustments, Continued
Step Action
7
Using an accurate pressure source, apply pressure equivalent to
desired upper range value to transmitter.
ATTENTION
For differential pressure transmitters, apply pressure
to the high pressure head and be sure that the pressure to the low
pressure head is at its reference value.
8
Check that milliammeter reading is 20 mA.
If reading … Then…
is not exactly 20 mA go to Step 9.
is correct go to Step 10.
ATTENTION
If you have the smart meter with local zero and
span adjustment option, you may substitute the smart meter readings
for the milliammeter readings. For example, with URV input pressure
applied assume that the meter reads 396 inH2O instead of 400
inH2O. In this case, the meter reading is less than 100% (or 20 mA).
9
a. Press and hold SPAN button on local zero and span assembly or
smart meter.
ATTENTION
The smart meter readings revert to the default unit of
percent (%) during this operation. If the error code Er0 appears on
the display, you are working with a model STD110 transmitter that
does not support the local zero and span adjustments. If the error
code Er4 appears, you are trying to set a SPAN value that is outside
acceptable limits for your transmitter. Readjust applied pressure to
be within acceptable range limits and repeat this procedure.
b. Press Increase button once to complete this function.
ATTENTION
The smart meter display goes blank for a 1/2
second and then returns reading 100%.
c. Check that milliammeter reading equals 20 mA and release SPAN
button.
ATTENTION
If milliammeter reading doesn’t change, be sure you
are not working with a model STD110 transmitter that ignores local
adjustments. The smart meter readings return to the set engineering
units after you release the SPAN button.
Continued on next page
2/05 ST 3000 Release 300 Installation Guide
57