GE DigitalFlow GS868, Руководство по программированию

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March 2008
1-16 Programming Site Data
Setting Up Inputs/Outputs
The following specific tasks may be performed via the
I/O
submenu:
•
Enter a zero cutoff value to eliminate low flow reading fluctuations
•
Set up fixed or live temperature and pressure inputs
•
Set up fixed or live steam quality input for mass flow calculations
While following the programming instructions, refer to the menu map
in Figure A-2 on page A-2 in Appendix A,
Menu Maps . Remember to
record all programmed data in Appendix B, Data Records .
1.
To enter the
I/O
submenu, press
[F4]
at the
Channel PROGRAM
prompt.
Entering the Zero Cutoff
Near zero flow, the Model GS868’s readings may fluctuate due to
small offsets caused by thermal drift or similar factors. To force a
zero reading when there is minimal flow, enter a zero cutoff value as
described below:
2.
Enter the desired Zero Cutoff value and press the
[ENT]
key. A
value of 0.1 ft/s (0.03 m/s) is recommended, but values from 0–1
ft/s (0–0.3 m/s) are acceptable. The menu returns to the main I/O
prompt.
Entering the Steam Input
3.
At the Assume Saturation prompt, press
[F1] = NO
to use
temperature and pressure to determine the state of the steam, or
press
[F2]
for the GS868 to assume the steam is saturated.
4.
At the Steam Input Type prompt, press
[F1]
to select a temperature
input, or
[F2]
to select a pressure input.
•
If you select
TEMP
, go to step 5.
•
If you select
PRESR
, go to step 7 on the next page.
Entering the Temperature
Input
5.
At the Temperature Input prompt, press
[F1]
to enter a constant
temperature value or press
[Fx]
to select the option card in
Slot x
that will supply the live temperature input.
Note:
Each slot that contains an option card with an analog input
assigned to
TEMP
or an
RTD
input will appear on the option
bar. If the process temperature is stable, a fixed value may be
used, but most applications require a live temperature input.