10
7. MAINTENANCE
7.1 Fault finding during commissioning
If a BA307C or BA308C fails to function during
commissioning the following procedure should be
followed:
Symptom
Cause
Solution
No display
Incorrect
Wiring
There should
be 1V
between
terminals
1 & 3 with
terminal 1
positive.
No display
and 0V
between
terminals 1
and 3.
Incorrect
wiring or
no power
supply.
Insufficient
loop voltage
to operate
indicator.
Check that a
current is
flowing in the
loop.
Check supply
voltage and
voltage drops
caused by all
components
in the loop.
Indicator
displays 1
Positive
over-range
The indicator
has been
incorrectly
calibrated &
is trying to
display a
number
greater than
1999.
Indicator
displays -1
Negative
over-range
The indicator
has been
incorrectly
calibrated &
is trying to
display a
number less
than -1999.
Unstable
display
4/20mA
input has a
large ripple
Check loop
supply
voltage.
7.2 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 BA307C or BA308C fails after it has been
functioning correctly, the following procedure
should be followed:
Symptom Cause Solution
No display
and 0V
between
terminals 1
and 3
No power
supply
Check that a
current is
flowing in the
loop.
Unstable
display
4/20mA input
has a large
ripple
Check loop
supply
voltage.
If this procedure does not reveal the cause of The
fault, it is recommended that the indicator is
replaced.
7.3 Servicing
All standard BA307C and BA308C indicator
assemblies are interchangeable and a single spare
may be used to replace any instrument which fails.
We recommend that faulty instruments and
instrument assemblies are returned to BEKA
associates or your local BEKA agent for
repair.
7.4 Routine maintenance
The mechanical condition of the instrument and
the electrical calibration should be regularly
checked. The interval between inspections
depends upon the environmental conditions. We
recommend that initially instrument calibration is
checked annually.
