IKA RH basic 2 Betriebsanleitung Seite 8

on the "Mot" dial (B) with a scale from 0 to 6 (C).
The scale values from 0 to 6 on this dial correspond roughly to speeds ranging
from 0 to 2000 rpm. The maximum speed of 2000 rpm is reached when the dial
switch is turned all the way to the right and there is no load on the motor.
Version RH digital KT/C: Set the motor speed using the "Mot" knob (B); the knob
has a graduated scale from 0 to maximum rpm.
The motor speed is shown on the LED display (D). When the motor is stopped
the speed "0" will be displayed. When the motor is operating, the display will
show the current speed in the range 100 to 2000 rpm.
Function Heating
The temperature of the heating plate of the instrument is kept constant by
a control circuit. In addition, it is monitored by a safety circuit. The required
temperature sensor (a thermo-couple) is installed in the heating plate. The RH
basic unit has a stainless steel surface plate with a heating output of 400 Watt.
RH basic KT/C and RH digital KT/C units have a enamel-coated stainless steel
surface plate with a heating output of 500 Watt.
Version RH basic and RH basic KT/C: The temperature of the heating plate can
be adjusted on the „Temp" turn dial (E) with a corresponding scale from 0 to 6
(F). The scale values from 0 to 6 correspond approximately to area temperatures
up to a max. of 320 °C. When the setting is at 0, the device does not heat the
medium up at normal room temperature.
During the heating phase, the signal light (I) lights up orange (orange = power is
being supplied to the heating plate; signal light off = no power being supplied)
Version RH digital KT/C: The temperature of the heating plate can be adjusted
on the „Temp" turn dial. When you change the knob setting, the LED display (G)
will the show the SETPOINT temperature and the warning light (K) will light up.
After approx. 3 seconds the LED display will switch back to showing the ACTUAL
14
temperature and the warning light (K) will switch off.
The temperature indication now constantly changes between actual temperature
(25 sec) and target temperature (5 sec).
When you select the SETPOINT temperature and as the unit heats up, the
warning light (K) will remain off and the LED display (G) will show the ACTUAL
temperature of the surface plate in the range from 0 °C to +320 °C.
The red warning light (J) will light up while heating is in progress. (Red warning
light ON = surface plate heating power supply is ON; red warning light OFF =
surface plate heating power is OFF).
PLEASE NOTE!
The heating plate of the version
RH basic KT/C and RH digital
KT/C only heats up, if the contact plug
has been plugged (the contact plug is
undetachably fitted to the instrument), or
if an ETC 1 and/or a contact thermometer
has been connected.
Limiter of safety temperature
The safety temperature limiter makes it possible to adjust the maximum
temperature of the heating plate (safety temperature).
This ensures that the temperature of heating plate does not exceed the flame
point of the material. The value to be set must be determined by trial and error
and should generally fall about 20 K below the flame point of the medium.
RH basic 2 devices have a safety circuit with a fixed setting that limits the
temperature of a heating plate to 400 °C.
RH basic KT/C and RH digital KT/C devices have an adjustable safety circuit. The
maximum temperature of the heating plate can be adjusted within a range from
100 °C to max. 400 °C.
Adjusting the safety temperature limit "Safe Temp" (Vers. KT)
Version RH basic KT/C and RH digital KT/C: The "Safe Temp" set screw (H) is to
the left of the "Temp" knob (E) on the front operator panel.
You can use the „Safe Temp" set screw (H) of the safety temperature limiter
to adjust the desired safety temperature. If the desired safety temperature is
exceeded by a higher adjusted target temperature, of if there is a defect in the
instrument controller, the heating turns off permanently in this state and the
stirring function continues to run at the speed that was set prior to the
malfunction.
• Using a straight-edge screwdriver, turn the "Safe Temp" adjustment screw (H)
as far as it will go clockwise (to the right).
• Do not turn the screw beyond the natural right or left limit of rotation, as this
will destroy the potentiometer.
• Use the "Temp" turn dial (E) to adjust the set-point temperature to desired
safety temperature ("Safe Temp").
• Turn the "Safe Temp" set screw (H) slowly to the left until the heating function
switches off and the signal light (I or J) goes off.
Wait for about one more minute to ensure that the signal light ( F ) going
off does not merely indicate the end of a switching cycle of the heater. If
the signal light (I or J) turns on again within this time, you must repeat the
procedure, slowly turning the "Safe Temp" (H) adjustment screw to the left
again.
When the signal light (I or J) does not light up again within one minute, the
safety temperature is correctly set.
• After this, turn set "Safe Temp" adjustment screw (H) back slightly to the right
(clockwise).
• After you have turned the unit switch (A) of and back on again, the device is
ready for operation.
NOTE: When the "Safe Temp" (H) adjustment screw is set to the minimum level
(as far as it will go to the left) the heating function is turned off.
Triggering of the safety circuit is shown in the following ways:
On the 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).
15