ABB 691HT Operating Instructions Manual page 37

T R I M M I NG A N D S E T U P
SNSR 4 - 20 LOOP CALI
TR I M TR I M TEST
S E N S O R T R I M , S E L E CT
T Y P E
FULL ZERO STAT
TRIM TRIM TRIM
Last i nput value used
LoVal = 0
H i Va l = 1400.000
LoVal = 0
H i Va l = 1400.000
L O W H I G H D I S P
T R I M T R I M L I M I T
L R L = - 2800.000
U R L = 2800.000
A p p l y a L o V a l P r e s s.
l o w e r t h a n H i V a l
P r e s s u r e s t a b i l i z i n g
- - - P L E A S E W A I T - - -
E n t e r a p p l i e d L o V a l
[ - 5 . 0 1 5 ] mmH2O
< - -- - - > C L R
Lo V a l = 0
H i V a l = 1400.000
L O W H I G H D I S P
T R I M T R I M L I M I T
A p p l y a H i V a l P r e s s.
h i g h e r t h a n L o V a l
W A R N I N G - loop may be
returned to auto
Use of the Green Keys - TRIM - Sensor Trimming - FULL TRIM
( for 600T, 600T EN and Deltapi K pressure transmitter )
CAUTION : remember that this procedure must be done by applying
input pressure, expecially when the choosen span is unfortunately
small (<5% of URL). If you don't apply input pressure, there will be
a permanent error in the output of the transmitter. Let us say that the
BRA
trimming operation on values <10% of URL, does not make better
instrument efforts on this span.
Starting from the top display press the F1 key ( SNSR TRIM ) : the
following display will appear.
Pressing the F1 key ( FULL TRIM ), a warning message is displayed:
"WARNING - Control loop should be in manual " and the label
PROCEED for the key F4.Pressing this key the following display
appears:
mmH2O
The display gives indication about the input values used during the last
mmH2O
trimming operation. This indication lasts for some seconds and is then
replaced by the new display below.
The same values are displayed but two labels appear for the keys F1 and
mmH2O
F2 , respectively LOW TRIM and HIGH TRIM, while the key F3 - DISP
mmH2O
LIM can be used to display the lower and upper range limits (LRL and
URL). Pressing the F1 a message is displayed asking the user to apply
the low pressure value.
If the Low Trimming value corresponds to zero and you are trimming a
mmH2O
transmitter other than absolute pressure, the atmospheric pressure can
mmH2O
be taken as reference or the bypass opened to equalize the pressure on
P R O
both side of the sensor. Care should be paid to the absolute pressure
C E E D
transmitters where a vacuum reference should be used or the actual
atmospheric pressure taken into consideration. After having applied the
pressure press the F4 to PROCEED.
The value of the pressure read by the transmitter is then displayed within
PRO
square brackets : this value can differ from the value read in the
CEED
reference meter. A blinking cursor is present in the most significant digit
: using the F1, to move left, or the F2, to move right, and the numerical
keypad introduce the value read on the reference pressure meter or zero
if appropriate. When the value is correctly introduced press F4 to
ENTER the value. If the value is incorrect then one of the following
messages is issued :
- Trim span too small
- Trim on negative side not allowed (for Deltapi K transmitter)
NOTE : Do not introduce change, on the value read, of more that 5%
of the URL at once. If this limit or pressure limits are exceeded a
message will be displayed ( see the relevant section of this
E N T R
manual ). The Communicator accepts the first five digits of the
input.
Small differences, of the order of the 0.003% of the URV, on the
mm H2O
reading, are tolerated.
mm H2O
The introduced value is sent to the transmitter: the usual blinking T
appears in the upper right corner of the display signalling that a
communication is on course. Right after the display at side appears
showing the modified value.
The procedure to trim the high value is the same: pressing the F2 key
the following message appears: proceed then as for low trimming.
PRO
Note: Do not attempt to apply, as Hival, a value resulting in a span
CEED
smaller than the minimum span and, for Deltapi K Pressure Tx
having a S/W Rev. up to 5.1 a negative value or a value too close to
zero. In this case the operation will abort and an error message is
displayed.
PRO
For best results perform a low trimming, a high trimming and a low
CEED
trimming again. To exit from the trimming procedure press ESCAPE :
the following display appears. Take note of it and then press PROCEED:
the display returns to the Sensor Trimming menu.
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