TE Technology TC-720 - Manual (Page 59)

OUTPUT BOX
This shows the percentage of maximum power output that the controller is providing to the TE device.
The output can be turned on and off by clicking the “OUTPUT ON/OFF” toggle switch. Whenever a change is made in the
software, the controller is updated in real time. However, it might be beneficial to turn off the output first and then make
all of your software/controller settings before turning on the output. If you are using the TC-720 OEM, be sure that the
output is set to ON prior to shutting down the software if you intend to run the controller stand-alone from the
computer. Otherwise, if you attempt to use the TC-720 OEM again without the software, you will not be able to turn the
output on.
The HEAT MULTIPLIER and COOL MULTIPLIER values scale the output power level by the product of the multiplier and
output power level. The HEAT MULTIPLIER could be set to 0.00, for example, and then the controller would behave
essentially as a cool-only controller. Alternatively, it could be set for some fractional value between 0.00 and 1.00. This is
useful if you were cycling between heating and cooling by manually entering two different set point temperatures, and the
controller had only been tuned for the cooling set point. TE devices are very effective heaters, so by reducing the heating
output, it may be possible to achieve good control stability for both temperatures by only adjusting the HEAT MULTIPLIER
rather than by having to manually enter two different sets of tuning parameters for each set point temperature.
The ANALOG OUTPUT MULTIPLIER values scale the analog output signal by the product of the multiplier. For example, the
controller typically provides a 0-10 Vdc analog signal that can be used with a programmable power supply. However, the
ANALOG OUTPUT MULTIPLIER can be set from 0 to 100% to proportionally reduce this maximum voltage. When it is set to
100%, the analog output voltage ranges the full 0 to 10 V. If it were set to 50%, then analog output voltage would range
from 0 to 5 V. This can be useful for limiting the output voltage of the programmable power supply, or for programmable
power supplies that require input voltages of less than 10V.
The analog output signal is generated by filtering and then buffering a PWM signal from the microcontroller.
Limiting the analog output signal with the ANALOG OUTPUT MULTIPLIER effectively reduces the maximum duty
cycle of the PWM signal before it is filtered and buffered. Thus, when using it, the number of discrete output levels
will also be reduced, thereby limiting the resolution of the voltage control. Because of this users may find it
preferable to keep the ANALOG OUTPUT MULTIPLIER set to 100% and use an external voltage divider.
OVER CURRENT LEVEL (in amps) determines when the controller will shut off output power to the TE device in the event the
current exceeds the indicated amount.
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