LAUDA Ultra-Thermostats
UB 20(-D), UB 25, UB 50, UB 30, UB 40
UB 20 F, UB 20 J, UB 30 J, UB 40 J, UB 65 J
UB 20 JL, UB 30 JL, UB 40 JL
YATE0013 / 10.04.02
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9.12.2
Temperature signal channel 2
Channel 2 is purely a voltage output at socket 52 S on pin 1. The selection is made as
described for channel 1 in Item 9.12.1 except that current ranges cannot be selected.
9.13 Safety
function
The operation of the safety devices of the units has already been described under
Item 4.1.
After starting up the user should confirm the correct operation of the safety devices. If
the unit operates without supervision we recommend that this check should be carried
out daily.
9.13.1 Low-level
cut-out
For a correct operation of the low-level cut-out it is essential that the float switch
operates correctly. To check this, lower the level in the bath by draining away some of
the liquid. When the bath level falls below the minimum level (approx. 20 mm above the
upper heater winding) the pump, the heating and the refrigeration unit switch off on all
poles.
The display shows the message
L
1
LEVEL
L
2
TOO LOW
and there is a warning beep.
To re-start fill up the bath and press the reset key
twice (with approx. 1 sec
interval).
9.13.2
Adjustable overtemperature limiter
To check it the switch-off point T
O
has to be set below the current bath temperature.
Note that an input of T
O
below the setpoint T
S
produces the message
L
2
T
S
>>
T
O
and the previous value for T
O
is retained.
Therefore the setpoint T
S
has to be lowered first by a few degrees before carrying out
this test.
The overtemperature switch-off point can then be set e.g. 1 K below the current bath
temperature.