If the signal is short circuit to ground it will have same effect as if the transmitter is discon-
nected. The position transmitters are supplied by 24 VDC from Unisab III. If the power supply
is short circuit to ground it will both affect the power supply for the position transmitters and
the power supply for the digital inputs. Therefore, the compressor will stop immediately be-
cause of missing digital inputs.
9.1.5 Internal clock, Date - Time
The Date and Time function is provided with a battery back-up. If the battery is dead the in-
ternal clock will not be running correctly after a power cut. If the power supply for Unisab III
fails, the clock will be reset to:
Hour: 19
Minute: 47
Second: 00
Day: 27
Month: 2
Year: 1970
The seconds will still be counting but for every 60 seconds the minute will switch from 47 to
48 and back to 47 again. The clock can be adjusted to the actual time and it will then be run-
ning correctly until the next power cut.
Unisab III continues operation even when the battery is dead. However, date and time must
be set correctly in order for the shutdowns to be stored with the correct time.
The internal clock can be checked in the menu Setup/Timers/Date-Time.
If the clock is not running correctly, replace the battery, see subsection 10.1.3. Replacing bat-
tery.
9.1.6 General instructions
Please note the following before performing any corrections inside the Unisab III control cabi-
net:
Unisab III may include live wires containing unknown voltage even though the supply voltage
to Unisab III is disconnected.
Before beginning the troubleshooting, disconnect the main supply to the compressor motor to
prevent it from starting up inadvertently.
An interruption of voltage to Unisab III will not cause any information loss, i.e. information
can be displayed again once the supply voltage has been restored.
9.2. Troubleshooting diagrams
If irregularities occur in connection with compressor operation, the problem can be located by
using the following troubleshooting diagrams:
Troubleshooting
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Engineering manual - Unisab III 1.10
001930 en 2014.09
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