The process of "alignment" consists in eliminating a systematic offset observed with a given sensor, around a specific operating point. It's important to understand that one compensates for an error in the process, not for an error linked to automation (process control). Therefore, replacing a module does not require a new alignment. However, replacing the sensor or changing the sensor's operating point does require a new alignment.
The following diagram shows conversion lines:
Suppose that a Pt100 probe, immersed in melting ice (typical adjustment procedure for probes), indicates, after measurement and display, that the temperature is 10°C, instead of 0°C. You have the option of aligning (or "mapping") this measurement to the desired value, namely 0. After the alignment procedure, the measurement channel will implement a systematic offset of -10 for any new measurement.
The alignment value is
editable from a programming console, even if the program is in RUN Mode.
For each input channel, you may:
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View and modify the desired measurement value,
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Save the alignment value,
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Determine whether the channel already has an alignment.
The alignment offset may also be modified through programming. Channel alignment is performed in the Standard operating mode, without any effect on the channel's operating modes.
The maximum offset between measured value and desired (aligned) value may not exceed +/-1000.
