Memmert ICH 256 Climate Chambers (Generation 2003) - Manual (Page 54)

54
Advanced Functions
7.3.1 Mechanical temperature monitoring: Temperature limiter (TB)
The cooled incubator is equipped with a mechanical temperature limiter (TB) of protection
class 1 in accordance with DIN 12880.
If the electronic monitoring unit should fail during operation and the factory-set maximum
temperature is exceeded by approx. 20 °C, the temperature limiter, as the final protective
measure, switches off the heating permanently. As a warning, the icon lights up. icon lights up.
Error rectification after the TB has been triggered: Error rectification after the TB has been triggered:
1. Switch off the appliance and leave to cool down.
2. Reset the TB by pressing the red button, located
on the rear side of the unit (next to the power
cord, see Fig. 23 ). Press until you hear a „click“
sound.
7.3.2 Electronic temperature monitoring
(TWW)
Temperature monitoring can be adjusted indepen-
dently from the operating modes.
The manually set monitoring temperature
MIN and and
MAX the overtemperature control is monitored by an
adjustable over/undertemperature controller (TWW) protection class 3.3 acc. to DIN 12880.
If the manually set monitoring temperature
MAX is exceeded, the TWW takes over
temperature control and begins to regulate the monitoring temperature ( Fig. 24 ).
The alarm icon flashes as a warning .
Setting MAX
Set
temperature
t
°C
Controller error
Emergency operation
Fig. 24 Schematic diagram of how the TWW temperature monitoring works
The monitoring temperature must always be set sufficiently high above the
maximum working temperature.
If the acoustic alarm is switched on in the SETUP, the TWW alarm is additionally signalled by
an intermittent tone. If the SET key is pressed, the acoustic alarm can be temporarily switched
off until the next alarm event occurs.
Fig. 23 TB Reset