Mantracourt Electronics Limited
ICA3 & 6 S and H Versions User Manual
9
Chapter 6 Trouble Shooting
1.
No Output
a)
Check power supply is present and the correct polarity
b)
Check the output connections are correct with no open circuit connections
c)
Check terminations (ensure there are no dry joints)
d)
Check the sensor is connected (typically reading 350 Ohm across & -) with the power off
e)
Check the Excitation voltage is correct
f)
Check the load is connected and is not open or short circuited
g)
Check Span and Gain calibration
2.
Low Output
This is when an output is present but not of sufficient magnitude to meet the required value. Remember to allow for
Tare Weight and ensure it is measured and allowed for in the output from the ICA.
a)
Check power supply is within specified limits (i.e. is not low)
b)
Check the sensor is connected (typically reading 350 Ohm across & -) with the power off.
c)
Check the Excitation voltage is at 5V dc
d)
Check the calibration
e)
Check the Zero (offset) is correct for the sensor, this too is a common reason for low outputs
3.
High Output
This is when an output is present but higher (in span or zero) than expected.
High output is not normally a problem. It is most likely to be incorrect connections and as such the output would be
high and fixed
a)
Check the sensor is connected (typically reading 350 Ohm across & -) with the power off
b)
Check the Excitation voltage is at 5V dc
c)
Check the Zero (offset)
d)
Check the calibration.
4.
Unstable Output
This is when the output is unstable or varies. The cause could be (a) poor installation or (b) a noisy environment.
Poor Installation -This is when an output is present but higher or lower (in span or zero) than expected:
a)
Check the installation for problems and repair where necessary
b)
Poor termination
c)
High resistance on cable leads
d)
Low insulation impedance
e)
Proximity to High Voltage Equipment – Transformers, Contactors, Motors etc.
Noisy Environment-
a)
Check if the source can be found and remove noise
b)
Check the cable shielding and ensure it is correctly installed and terminated.
5.
Calibration
This section assumes that the unit is providing an output that is not stuck at top or bottom of the scale.
(See paragraphs 1-3 if this is the case)
Ensure you are connected to the correct sensor and not to another adjacent unit.
Ensure you have the correct calibration data from the sensor manufacturer. This must include a certified table with
offset, zero and linearity.
Ensure you have the calibration set-up correctly installed i.e. mV source and output as required.
Ensure the temperature and other environmental parameters are within specification and where necessary taken
into account when calibrating should such parameters have an effect on the calibration.
6.
Fine Span (Gain) and Zero (Offset) Adjustment Problems
If the adjustment cannot reach the maximum output desired then, check the tare is not too high.
If the potentiometer does not alter the output the unit must be repaired – remove from service.
It is always wise to check a known good ICA against the problem installation before rejecting the suspect ICA.
