DETAILED PARAMETER DESCRIPTIONS
Introduction
The block diagram in Figure 3.1 shows the internal functions associated with the
final output to the TEC. Use this diagram while learning about the parameters in the
Main Menu below:
1. Percent Current.................................. [pcnt]
This is the percent output current of the Series 800/850 TEC Controllers. The voltage at the “+”
terminals is fixed at the specified voltage +2V (i.e. a +15V output would be between +15V to +17V).
2. Proportional Band 1.............................. [pb`1]
This is the Cooling Proportional Band.
Set this to a reasonable value that doesn’t cause oscillation. Think in terms of temperature. For
instance, if you are using a thermistor, give it several Kohms (i.e. 5.00) for starters and adjust it from
there. For temperature units in degrees, use something around 10.0 degrees for a starting point. This
is merely a suggestion. The value you choose will be based on the thermal response of the TEC. This
response is variable and based on the thermal load placed between the sensor and the surface of the
TEC.
Do not set [pb`1] to zero unless on/off control is desired! Using on/off control incorrectly can
damage the mechanical relays inside the Series 800/850 temperature controller!
3. Integral Term 1.................................. [It`1]
This is the Cooling Integral Term (or “time”).
Set this to match the thermal response of the load being controlled. If set too low, it
may cause oscillation, however, if set too high, it may take a long time to reach the set
point temperature.
4. Derivative Term 1................................ [de`1]
This is the Cooling Derivative Term.
This is a powerful term and setting it too high will make the system sluggish. Many
people choose to turn the Derivative Term off by setting it to 0.
5. Proportional Term 2.............................. [pb`2]
This is the Heating Proportional Band. Set this to a reasonable value that doesn’t cause oscillation.
Think in terms of temperature. For instance, if you are using a thermistor, give it several Kohms (i.e.
5.00) for starters and adjust it from there. For temperature units in degrees, use something around
10.0 degrees for a starting point. This is merely a suggestion. The value you choose will be based on
the thermal response of the TEC. This response is variable and based on the thermal load placed
between the sensor and the surface of the TEC. Do not set [pb`2] to zero unless on/off control is
desired! Using on/off control incorrectly can damage the mechanical relays inside the Series 800/850
temperature controller.
ALPHA OMEGA INSTRUMENTS CORP. Instruction Manual
Series 800/850 Thermoelectric Cooler Controller Page 52
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