46 Trouble Shooting
HP289
Scaling Factor should be set to 1 and the Resolution to whole
numbers.
Counting erratically
This can be caused by two factors:
§ Setting the input circuit incorrectly
§ Lack of shielding on the input wiring
Ensure that the input selection DIP switch is correctly set for the
flowmeter attached. Shield the input signal with the shield
connected at the batch controller only.
Instrument acting erratically
Erratic operation can be the result of severe electrical interference.
Considerable attention has been given to designing the Batch
Controller to withstand electrical interference.
However, in extreme cases, loads may be encountered which are
exceptionally inductive and may require additional protection.
One measure is to use an RC Suppression Network as described in
the previous section of this manual.
Another remedy for this problem is to use an isolating relay to
switch the load and use the Batcher to drive the isolating relay.
The isolating relay should be mounted away from the Batcher and
from the signal wiring.
No end of batch, pulse output, or flow alarm
This fault is usually caused by lack of a pull-up resistor or load on
the output. The outputs have no internal pull-up resistors and
require on an external load.