9
7. MAINTENANCE
7.1 Fault finding during commissioning
If the BA304NC fails to function during
commissioning the following procedure should be
followed:
Symptom Cause Solution
No display
Incorrect
There should be 1V
wiring
between terminals 1 &
3 with terminal 1
positive.
No display
Incorrect
Check that a current
with 0V
wiring or
is flowing in the loop.
between no
power
terminals 1
supply.
and 3.
Insufficient
Check supply voltage
loop voltage and voltage drops
to operate
caused by all
BA304NC.
components in the loop.
No display
Indicator
Check that the three
with 4V
assembly
screws securing the
between
not correctly indicator assembly are
terminals 1
installed in
tightened.
and 3
enclosure.
BA304NC
Positive
The BA304NC has been
displays 1
over-range
incorrectly calibrated &
is trying to display a
number greater than
1999.
BA304NC
Negative
The BA304NC has been
displays -1
over-range
incorrectly calibrated &
is trying to display a
number less than
-1999.
Unstable
4/20mA
Check loop supply
display
input has a
voltage.
large ripple
7.2 Fault finding after commissioning
CAUTION!
ENSURE PLANT SAFETY BEFORE
STARTING MAINTENANCE
Live maintenance should only be
performed when there is no risk of a
flammable atmosphere being present,
and dust or water can not enter the
enclosure. Before replacing enclosure
cover ensure that the sealing gasket is
undamaged and free from dirt and
foreign bodies.
If a BA304NC fails after it has been functioning
correctly, the following procedure should be
followed:
Symptom Cause Solution
No display
No power
Check that a current
with 0V
supply
is flowing in the loop.
between
terminals 1
and 3
No display
Indicator
Check that the three
with 4V
assembly
screws securing the
between
not correctly indicator assembly are
terminals 1
installed in
tightened.
and 3
enclosure.
Unstable
4/20mA
Check loop supply
display
input has a voltage.
large ripple
If this procedure does not reveal the cause of the
fault, it is recommended that the indicator
assembly is removed from the enclosure and
replaced. This can be done without disconnecting
power. If the replacement assembly functions, the
fault is within the original indicator assembly. If the
indicator is still faulty, it is likely that the fault is
within the enclosure assembly or field wiring.
