Note: Immediately the
Up
or
Down
button is operated the annunciator in the
top left hand corner of the display will
be activated to warn that any change in
the input signal will be ignored while this
display correction is being made.
Operating the
P
push-button will lock
the transmitter display at -10.0
and
allow the output current to be trimmed
using the
Up
or
Down
button. When the
output current measured by a DVM is
4.000mA, the
E
push-button should be
operated to return the transmitter to the
'ZEro' prompt.
This completes calibration at -10.0
o
C.
Step 13 Span adjustment
With the transmitter displaying the
'ZEro' prompt select 'SPAn' by pressing
the
Up
or
Down
button. With the
thermocouple heated to 240
o
C, or an
equivalent voltage input, push
P
which
will cause the transmitter to display the
thermocouple temperature. Adjust the
display with the
Up
and
Down
buttons
until it is 240.0
Note: Immediately the
Up
or
Down
button is operated the annunciator in the
top left hand corner of the display will
be activated to warn that any change in
the input signal will be ignored while this
display correction is being made.
Operating the
P
push-button will lock
the transmitter display at 240.0
and
allow the output current to be trimmed
using the
Up
or
Down
button. When the
output current measured by a DVM is
20.000mA, the
E
push-button should be
operated to return the transmitter to the
'SPAn' prompt.
This completes calibration at 240.0
o
C.
Pressing the
E
push-button again will
return the transmitter to the display
mode.
9. MAINTENANCE
The instrument should only be maintained by trained
competent personnel.
9.1 Fault finding during commissioning
If the BA378C transmitter fails to function during
commissioning the following procedure should be
followed:
Symptom Cause Solution
No display
Incorrect
Check wiring
or output
wiring or no
and power
current
power supply
supply polarity
Check that voltage
between
terminals
5 & 6 is between 10
and 30V with terminal
5 positive.
BA378C
Positive
The transmitter input
displays 1
display
exceeds the upper
over-range
operating range of the
selected THC or RTD.
For voltage inputs,
display is incorrectly
calibrated.
Check calibration.
BA378C
Negative
The transmitter input
displays -1
display
is less than the lower
over-range
operating range of the
selected THC or RTD.
For voltage inputs,
display is incorrectly
calibrated.
Check calibration.
Output fixed
4/20mA output The transmitter output
below 4mA
current over,
current is incorrectly
or above
or under-range calibrated.
20mA.
Check calibration.
9.2 Fault finding after commissioning
ENSURE PLANT SAFETY BEFORE
STARTING MAINTENANCE
Live maintenance is permitted on
intrinsically safe equipment installed in a
hazardous area, but only certified test
equipment should be used unless a gas
clearance certificate is available.
If a BA378C fails after it has been functioning
correctly the procedure shown in section 9.1 should
be followed.
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