Operation
Modline 5
89
The CHK and Auto Cal Hour functions are different for the Series 56 Models. Separate explanations
and instructions are provided for Series 56 Models on the pages that follow.
The HOUR function provides for selection of an automatic System Check. This function automatically
initiates the check described above. A selection of OFF or a time interval in hours between checks is
offered.
A manual Check from the Sensor Keyboard, as explained above, or by RS-485 Communication will start
a new period, but not change the value of the interval. This will start a new interval.
Process temperature measurement and control requirements need to be considered when using this
automatic function. Real time process temperature measurement and signal conditioning is suspended
for up to ten seconds.
Continuous interval setting should be 8 hours or greater. A 168 hour, 1 week, (or greater) automatic
interval and manually initiated checks are the recommendations that will provide minimal
measurement interruption.
Navigate from TEMP display with
&
▲▼
to ENGR then use
&
▲▼
to Hour
Display
Instructions
Display and Limits
HOUR
Press ENT to view Automatic Check selection, OFF or numerical value
representing hours between Checks.
Use Up / Down Arrows to change selection and setting.
See above recommendations.
Press ENT
to save and return to TEMP display.
OFF or
Value 1 to 9999
5.6.6
CHK – Manual System Calibration for 56 Models
This function checks a Model 56 Sensors performance by initiating a System Calibration Check. When
this function is initiated, the Sensor’s infrared detector signal, internal gain and offset voltages are
checked. First, a flag is closed inside of the unit to block the optical path of the instrument. Operation of
the Sensor is determined with no target in the field of view of the infrared detector. Second, a calibration
source with a known radiance is activated inside the Sensor and the radiance is “seen” by the infrared
detector. The response of the sensor electronics to the radiance is compared to an expected value.
If the Calibrate Check determines a Model 56 Sensor requires recalibration, the sensor firmware
performs a Self-Calibration adjustment. Typically, only small changes in calibration will occur.
During the Calibration Check, the Sensor Rear Panel TEMP display indicates CAL. The Alarm Led
indicator and Alarm Relay remain at their last condition. Target temperature measurement is
suspended. The Analog Output is held at its last output value. The Analog Output readings are not
derived from real time temperature measurement during Calibration Check function. Peak Picker,
Track and Hold and Response time functions are suspended. At the end of the cycle, operation returns
to normal and real time temperature measurement resumes.
Temperature indications may shift slightly upon return to normal operation.
A Calibrate Check is required for to insure accurate operation of the Series 56 Sensors and should be
performed routinely, every 168 hours or less. The check can be initiated by any of the three methods
