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4.6.1 Heater Outputs 95
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In the Monitor Out mode the control input parameter is used to determine the source
of the output voltage.
A special case exists when a scanner is attached, autoscanning is enabled, and a mea-
surement input channel is selected as an output’s control input. Details regarding the
change to the control algorithm as a result of this special case are described in section
4.6.1.6.1.
An input can only be assigned to one output at a time. If an input is assigned to a new out-
put, the previous output will have an input setting of “none.”
If the measurement input control channel is manually changed during control, the instru-
ment will attempt to minimize disturbance to the load by choosing the reading value
from the new channel as the setpoint when controlling in ohms.
If there is not a curve assigned to the control input, the appropriate temperature coeffi-
cient must be selected in the input setup menu (section 4.4.8) or the PID control algo-
rithm will not operate properly.
Menu navigation:
Output Setup (Sample Heater, Warm Up Heater, or Analog/Still)
Q
Control Input
Q
(None, Input A, 1-16)
Default:
Sample Heater: Input A
Warm Up Heater: Off
Analog/Still: Off
Interface command:
OUTMODE
4.6.1.5.2 Proportional (P)
The proportional parameter (also called gain) is the P part of the PID control equation.
It has a range of 0.001 to 1000 with a resolution of 0.001. The default value is 10.
To set P, first configure the output mode of the desired heater to Closed Loop PID
mode (section 4.6.1.4). Then press
Sample Heater or Warm-Up Heater to display the
respective control loop information if it is not already displayed. Then press PID/Man
Out . This will cause a temporary Control Setup menu to be displayed allowing the P
value to be set.
Menu navigation:
Sample Heater or Warm-Up Heater
Q
PID/Man Out
Q
Proportional (P)
Q
(0.001 to
1000)
Default: 10
Interface command:
PID
4.6.1.5.3 Integral (I)
The integral parameter (also called reset) is the I part of the PID equation. It has a set-
ting range of 1 to 10,000 s. A setting of zero turns I off. The default value is 20 s.
To set I, first configure the output mode of the desired heater to Closed Loop PID mode
(section 4.6.1.4). Then press
Sample Heater or Warm-Up Heater to display the
respective control loop information if it is not already displayed. Then press PID/Man
Out . This will cause a temporary Control Setup menu to be displayed allowing the I
value to be set.
Menu navigation:
Sample Heater or Warm-Up Heater
Q
PID/Man Out
Q
Integral (I)
Q
(1 to 10,000)