Thermo Scientific ThermoFlex Manual De Instrucciones página 196

The following values reflect the standard scaling and are the factory defaults:
Voltage (0v – 10v = the operating range of the chiller)
High volts
Low volts
High temp
Low temp
Voltage
With highlighted press enter to display:
USER VOLTAGE
High Volts
Low Volts
High Temp
Low Temp
These values are used to calculate a gain and offset and are applied to the setpoint input voltage.
The default settings for a high temp chiller will yield the following gain and offset for setpoint input:
Now 10v will yield a setpoint of 90°. (10 * gain) + offset
It could just as easily be configured for other ranges such as:
1v – 9v = 5° - 150°. However the chiller will only recognize a set point between 5° - 90°.
A separate gain and offset is also be calculated and are applied to the DAC temperature output value.
The default settings for a high temp chiller will yield the following gain and offset for temperature output:
Now 90° will output 10v. (90 * gain) + offset
Thermo Scientific
10.0v
0.0v
40.0° (standard temp chillers), 90.0° (high temp chilers)
5.0°
10.0
0.0
40.0
5.0
VoltageInputGain = (high temp – low temp) / (high volt – low volt)
VoltageInputOffset = high temp – (high volt * VoltageInputGain)
VoltageInputGain = (90 – 5) / (10 – 0) = 8.5
VoltageInputOffset = 90 – (10 * 8.5) = 5
(10v * 8.5) + 5 = 90°
VoltageOutputGain = (high volt – low volt) / (high temp – low temp)
VoltageOutputOffset = high volt – (high temp * VoltageOutputGain)
VoltageOutputGain = (10 – 0) / (90 – 5) = 0.117647
VottageOutputOffset = 10 – (90 * 0.117647) = -0.58823
(90° * 0.117647) + (-0.58823) = 10.0v
Highlight the desired value and then press enter, the high-
light will flash. Use the up and down arrows to change the
value. Once the desired value is displayed press enter to
accept the change and stop the flashing.
Appendix D
ThermoFlex D-5