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
- 40 -
9.7.2
Start of external control
Connect platinum resistance thermometers to both of the Pt 100 inputs 10 S (T
1
and
T
2
). It is sensible but not essential to use T
1
if only one input is in use.
The external control with the measuring point T
1
is switched on with the key
in the
SHIFT mode; pressing the key again switches to T
2
as control variable.
Pressing the key
once more (SHIFT ON) switches back to the bath control
(internal) T
i
.
In L
2
the position before the final one shows the parameter used as control variable.
L
2
T
S
= 120.35
T
i
I
T
1
T
2
This setting remains stored in case of a fault or after the power is switched off.
If T
1
is selected but no probe has been connected the message
L
1
Ext Pt 100 not
L
2
connected
appears.
The unit then switches the control variable to T
2
automatically. If T
2
is also not
connected, the thermostat switches to T
i
.
When changing the setpoint for more than 10°C it may be possible to achieve an
improved control result by re-starting the external control from the control variable T
i
(with SHIFT
).
After power OFF the unit operates with control from the bath (T
i
) for safety reasons;
external control must be re-selected after power ON as explained above.
9.7.3 Notes
When operating with external control it is essential to ensure that the probe for the
control variable is in good thermal contact with the liquid, otherwise a poor control result
must be expected, or the control may be completely ineffective.
Proceeding from the control parameters used for bath control the control may have to be
adapted either by auto-adaptation (see Item 9.4.1) or by the input of the control
parameters.
Important: Set the overtemperature switch-off point T
O
(see Item 9.3.4) sufficiently high
since the bath temperature may under certain circumstances become much higher than
the setpoint.