J-KEM Scientific Gemini User Manual - page 19
19
3.7
Temperature Sensor Input.
Both channels of the controller are fitted with a specific
type
of
thermocouple input and can only be used with a thermocouple of the same type. For the correct
temperature to be displayed, the thermocouple type must match the receptacle type on the front of the
controller (Figure 1; #’s 8 & 12). All thermocouples are color coded to show their type (Blue = type T;
Yellow = type K; Black = type J). The color of the thermocouple plug must match the color of the
receptacle on the front of the controller. If the thermocouple is broken or becomes unplugged, the error
message "
inPt" "FAiL"
blinks in the temperature meter display and the controller stops heating.
3.8
Affect of Power Setting on Heating Profile.
The following graphs show the affect of
selected power levels on heating performance in a variety of situations. Each example contains 1 optimal
and 1 or 2 less optimal settings demonstrating use of the output power level.
0
1
0
2
0
3
0
40
50
60
70
2
0
3
0
4
0
5
0
6
0
7
0
8
0
C
o
n
d
i
t
i
o
n
s
:
Set point = 75 C
L
a
b
o
r
a
t
ory oven
o
P
o
w
e
r
S
etting = 50 - 500 ml
P
o
w
e
r
S
etting = > 2L
C
o
n
d
i
t
i
o
n
s
:
Set point = 45 C
H
P
L
C
C
olumn wrapped with heating tape
P
o
w
e
r
S
etting = 50 - 500 ml
o
T
e
m
p
C
o
T
i
me (min)
2 0
3 0
4 0
5 0
6 0
7 0
8 0
0
1 0
2 0
3 0
4 0
5 0
6 0
7 0
Temp.
o
C
Time (min)
Power Setting = 10-100 ml (i.e., 10% power)
Power Setting = 50-500 ml (i.e., 25% power)
Power Setting = 300 ml - 2 L (i.e., 50% power)
Conditions: Set point = 70
o
C
50 ml Toluene
100 ml Round bottomed flask
Graph 1
This graph shows typical
heating profiles for a
laboratory oven and an HPLC
column. In the example of
the oven the heating curves
for 2 different power levels
are shown. The 50 - 500 ml
setting is the appropriate
amount of power to heat to
75o C and thus results in a
smooth heating curve. The
> 2L power setting is too
much power and results in
oscillation around the set
point.
Graph 2
This graph shows the affect
of different power settings
when heating liquids with
heating mantles. The 10 -
100 ml setting (10% power)
is underpowered and results
in slow heating. The 300 ml
- 2 L setting (50% power) is
too much power and results
in sporadic control. The
controller adapts to a wide
range of power settings. In
this example the power is
varied by a factor of 5X,
nevertheless, reasonable
control is maintained in each
case.