IKA RH basic 2 - Manual (Page 15)

15
RH b2dKT
Triggeringof the safety circuit is shown in the following ways:
On RH basic 2 and RH basic KT/C versions: the warning light (I)
will flash two times per second. (Note: regular flashing indicates
that the safety circuit has been triggered; this warning light
remains permanently lit to indicate that a standard heating cycle is
in progress).
On the RH digital KT/C version: the letter ”-S-” will be shown on
the LED display (G).
The control of the medium temperature via ETC 1 or contact-ther-
mometer should be preferred. Its advantages are: just a short hea-
ting-up phase after setting the rated temperature, practically no
temperature drift and only a minor temperature waviness.
The rear of the instrument houses the diode bushing for connec-
tion the ETS-D or contact thermometer, or for plugging the contact
plug.
The elektronics of the instrument supply a test current that
has to flow over plug pins 3 and 5 of the diode bushing in
order for the heating plate to heat.
The rated temperature is set on the contact thermometer by
means of the rotary magnetic head, whereby the upper edge of
the traveling nut is the reference point on the rated value scale.
The required surface temperature of the heating plat is presel-
ected on the temp-rotary knob of the instrument.
If the temp-rotary knob is set to the maximally adjustable tempe-
rature, the heating-up takes place as rapidly as possible, yet the
medium temperature overshoots the rated value set on the
contact thermometer.
If the temp-rotary knob is set to twice the rated value, the result
is good compromise between rapid heating-up and overshooting.
If the temp-rotary knob is set precisely to the rated temperature,
the medium does not reach the rated temperature owing to a drop
in temperature between heating plate and medium.
The rated temperature is seting on the ETS-D.
If you are using an ETS-D4, we recommend using the ETS-D4 in
On/Off mode (two-point control) at higher medium temperatures.
Controlling the Medium Temperature
via ETC 1 or Contact Thermometer
Safety contact thermometers
acc. to DIN 12 878 class 2 or acc. Gerstel are connected with a
three-wire cable, the test current flows through the contact ther-
mometer.
Safety function:
If the test current is interrupted because of e.g. breakage of contact
thermometer or falling out of the cable plug, the heating cuts off.
Conact thermometer without safety circuit
acc. to DIN 12 878 class 0. The instrument only heats if the test
current circuit is closed by an electrical connection of the plug
pins 3 and 5.
2-wire connecting cables:
Connect plug pins 3 and 5 of the instrument plug.
3-wire connecting cables:
Here the test current circuit can also be produced in the terminal
head of the contact thermometer (connect plug pins 2 and 3).
A 3-wire cable with the required bridge is available (accessories).