24
Delay Heating for a Set Period of Time
In this mode, the user enters an amount of time to delay before
turning on power to the heater. This is useful to start heating a
reaction or piece of equipment automatically at a specific time.
While at this setting and while entering a time into the timer, no
power is applied to the heater.
Step 1.
When the timer displays “t-on”, holding
the timer knob in for 1 second causes the display to
change to a clock that shows 00 : 00. The left 2
digits are hours and the right 2 digits are minutes.
The minutes digits are blinking which indicates
that their value can be changed.
Hold in the timer
knob for 1 second
Step 2.
To increase the number of minutes, rotate
the timer knob to the right. To decrease the
number of minutes, rotate the timer knob to the
left.
Rotate the knob
to enter minutes
Step 3.
To change the number of hours in the
display, momentarily press the timer knob (1/4
second) and the hours digits begin to blink. To
increase the number of hours, rotate the timer knob
to the right. To decrease the number of hours,
rotate the timer knob to the left.
Rotate knob to
enter hours
Momentarily push knob
to lock in minutes
Step 4
. When the desired time is displayed, hold
in the timer knob for 1 second to enter the time and
start the timer. When the timer starts, the LED
under the label “ON at Zero” lights. This
indicates that power to the heater will turn ON
when the timer counts down to zero.
Hold in timer knob for
1 second to store time
and start timer
At any time, the timer program can be aborted by
holding in the timer knob for 1 second. When this
is done, the display changes to t-on. To turn on
heating, push the timer knob until the display reads
On.
Hold in knob
for 1 second
3.6
Output Power Level
This circuit (Figure 1, #’s 10 & 11) is the user’s interface to J-KEM’s patented
power control computer which limits the maximum output power delivered by the controller. It determines
whether the controller heats at a very low (1-10 mL), low (10 - 100 mL), intermediate (50 - 500 mL),
medium (300 mL - 2 L), or high (>2 L) power level. The power level set for Channels 1 & 2 are
independent of one another.
The output power circuit acts as a solid state variac. This circuit has an additional setting: “Heat Off”
which, when selected, turns heating off and allows the controller to act as a digital thermometer. The table
to the right shows the maximum output power from the controller to the heater depending on the position of
the power switch. The correct setting for this switch is the setting that supplies adequate power for the
heater to heat to the set point in a reasonable period of time while at the same time not overpowering it.
See
Section 4.4 for a detailed explanation of how to correctly set up a reaction using your J-KEM
controller.
