Lakeshore 336, Руководство пользователя

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4.5.1 Heater Outputs 67
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4.5.1.5.6 Setpoint
Use the Setpoint parameter to set the desired load temperature for a control loop.
Before entering a setpoint, a control loop must be created by configuring an input
sensor and assigning it to a control output using the Control Input parameter. The
Setpoint can be entered in either temperature units or sensor units, based on the sen-
sor input’s Preferred Units setting. The Setpoint Ramping feature is available when
controlling in temperature units to provide smooth, continuous control from one
temperature to the next. Refer to section 4.4 for details on Input Setup. Refer to sec-
tion 4.5.1.5.1 for details on assigning a Control Input. Refer to section 4.5.1.5.7 for
details on the Setpoint Ramping feature.
Most applications require control in units of temperature. To control in units of tem-
perature, set the Preferred Units parameter of the control input sensor to either kel-
vin or Celsius. When controlling in temperature, the available setting range of the
setpoint is limited by the Setpoint Limit parameter of the assigned temperature
curve. Refer to section 4.4.13 for details on setting the Preferred Units parameter.
Refer to section 5.8.1 for details on setting a curve Setpoint Limit.
The Setpoint Limit feature only limits the Setpoint entry. For even greater protection, the
Temperature Limit feature can be used to turn off all heater outputs if a sensor reading
above the specified temperature is observed. Refer to section 4.4.12 for details on the
Temperature Limit feature.
There are some instances when temperature control in sensor units may be desired,
for example when a temperature curve is not available. For these applications the
Model 336 can control temperature in sensor units. To control in sensor units, set the
Preferred Units parameter to Sensor. When controlling in sensor units, the Setpoint
resolution matches the display resolution for the sensor input type given in the speci-
fications (section 1.3).
Temperature control in sensor units can be unpredictable since most sensors do not have
a linear response to temperature, and therefore have can have different sensitivity in dif-
ferent temperature ranges.
If you change the Preferred Units from Sensor to temperature (Kelvin or Celsius), or
from temperature to Sensor, the Model 336 uses the assigned temperature curve to
convert the Setpoint to the new control units. This provides minimal disruption in the
control output if you change the Preferred Units parameter while the control loop is
active.
Menu Navigation:
Setpoint
Q
(See note below)
Default: 0.0000 K
Interface Command:
SETP
When controlling in temperature, setpoint is limited by the control input temperature
curve’s Setpoint Limit. When controlling in sensor units, setpoint is limited by the limits of
the configured control sensor.