Control Unit, Control And Safety Circuit - Lauda Integral T 1200 Operating Instructions Manual

Integral T process thermostats
4.7

Control unit, control and safety circuit

Tilting the control unit with display
The equipment is provided with a 2-line LC display to indicate the measurements and settings as
well as the operational status. The setpoint and other settings are selected under menu guidance
using two or three keys.
A Pt100 temperature probe senses the outflow temperature inside the bath. The measurement is
processed by a high-resolution AD converter. Further processing involves a special control
algorithm to operate the heating triac (with reduced reaction on the mains supply), the automatic
compressor control, and the cooling control which operates with low-noise solenoid valves. The
LAUDA proportional cooling principle permits control in the cooling range without any energy-
wasting counter-heat.
On single-phase units (T 1200 – T 2200 W) the maximum heater power is reduced to 1500 W while
the compressor is running in order to limit the current uptake.
An external Pt100 for sensing an external temperature can be connected to a socket (10S). This
value can be indicated and used (if required) as controlling variable when the external controller
(cascade control) is activated. The system is then controlled from the external measurement and
not from the outflow temperature
The safety system corresponds to that for laboratory liquid thermostats and conforms to
DIN EN 61010-2-010. A double-channel system is employed with the two micro controllers checking
each other. There is a low-level sensor and a second bath temperature probe (Pt100) used in the
safety circuit to switch off in case of over temperature and for checking the measuring/ control probe
The over temperature switch-off point is adjusted with a screwdriver (tool) on the control unit. The
setting is also automatically indicated on the display.
With low liquid level, over temperature and certain system faults the heating is switched off on all
poles. The pump and refrigeration unit are also switched off. This fault shut-down is permanent, i.e.
the blockage is stored in the memory and has to be reset by operating the key
been rectified. The fault blockage is retained after the mains supply is switched off.
Other equipment functions are described in the appropriate Sections and in Section 7.
21/01/2019 / YAWE 0026
Better readability of the display
The control unit can be tilted to two positions. This increases
the readability of the display. Carefully pull the bracket on the
control unit forwards and upwards. The control unit engages
in two positions.
Equipment description
after the fault has
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