PC3000 Complete Installation guide iss 12 - Elektro-Trading

PC3000 - Installation Guide iss. 5
4 Channel Analogue Output Module
(8) Change the parameter Cal_Mode from HCal_Hi to (Save) in order to store
the new calibration data. On completion of the save operation the Cal_Mode will
automatically revert to Run and Status_Info will indicate Ok.
(9) In the event of an error occurring whilst calibrating e.g.entering the wrong value
for the measured voltage, the calibration procedure may be aborted by changing
Cal_Mode from HCal_Hi or HCal_Lo to Run. The calibration data that existed
prior to the session will be restored.
The examples given assume that the channel being calibrated is in voltage mode.
Current channels may be calibrated in a similar fashion. As an example say a 0 to
20mA output channel produces 3mA in response to a request for 10% (2mA). A
reading of 3mA corresponds to 15% and this value should be entered into the
parameter Hw_Cal_V. (Tip: halve the value read from the meter and multiply by 10
to get percentage of full scale)
This procedure must be repeated for each channel. Note that there only need be one
calibration in voltage mode, and one in current mode, as the alternative ranges are
subsets and use the same calibration values.
Calibration dates on the Analog Out function block
The Analog_Out function block provides a calibration date:
Hw_Cal_Date
This represents the date of last hardware calibration for the currently selected
configuration (Voltage or Current)
Note: From Fb V3.00 words calibration dates are not supported.
There is no method for entering a date into the parameters. Future
releases will provide a facility to permit this. Calibration dates on
older versions should be ignored.
Other parameters associated with calibration
The Analog_Out function block provides two calibration point ‘outputs’:
C_Hw_Cal_Hi
C_Hw_Cal_Lo
This is the data read from the module at initialization and represents the value of the
calibration points used on the last calibration of the currently selected range.
Transducer calibration
Transducer calibration provides a method of scaling and offsetting non-standard
output ranges. It also provides a means for correcting actuator errors e.g. 100% or
10V output does not correspond to valve fully open due to valve inaccuracy.
The PC 3000 analog output module uses a two point transducer calibration scheme in
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