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SLICE-QTC Four-Channel Temperature Controller
Product Manuals - https://www.vescent.com/manuals/
Offset[˚C]. Touch the Settings icon to the right of the channel selection to adjust the Gain and Offset.
This mode comes with both an absolute, and relative option, which can be selected separately
through the I/O menu.
External Temperature Input
This mode allows a bypass of the temperature read from a thermistor on a plant to use a temperature
from a device that generates voltage as a function of temperature. The temperature is related to the
input voltage (V
in
) by: Temperature [°C] = Gain x V
in
+ Offset. Touch the Settings icon to the right of
the channel selection to adjust the Gain and Offset.
External Error Input
This mode allows the temperature error to be derived from an external temperature transducer. In
this mode, the thermistor and associated signal processing electronics are not used. The temperature
error is related to the input voltage Vin by: Temperature Error [˚C] = Gain [˚C/V] x Vin + Offset [˚C].
Touch the Settings icon to the right of the channel selection to adjust the Gain and Offset.
Feedforward
This mode allows a feedforward signal to be summed into the output of the PID loop filter. The
feedforward signal current is related to the input voltage Vin by: Feedforward Current [A] = Gain[A/V]
x Vin + Offset[A]. Touch the Settings icon to the right of the channel selection to adjust the Gain and
Offset.
Slow Servo Input
In some use cases, it is convenient to have the temperature set point automatically adjusted to keep
another external parameter (which depends on temperature) at a certain value. For instance, the
frequency of a laser might be controlled by adjusting the cavity length via a piezoelectric transducer
(PZT). Over time, the cavity length may drift outside the range of the PZT, causing the laser to unlock.
In this case, the laser cavity might have its temperature automatically adjusted so as to center the
PZT voltage in the middle of its operating range.
When this mode is active, the input signal is compared with a set point voltage (settable by the user)
to derive an error signal that is input to a single integrator loop filter. The output of the integrator
automatically adjusts the the temperature set point to maintain the input voltage signal at set point
voltage. When the slow servo is enabled for a channel, the temperature setpoint field for that channel
on the home screen will be highlighted blue, as shown in (
