Maintenance
Controller Calibration
Factory calibration
Factory calibration of controller components is performed before shipment to 0.1% accuracy. Calibration values are contained in a number of the controller components, namely: the CPU, Backplane, and AI and AO modules.
Figure 32 shows the various components in which calibration data is stored.
•Calibration functions and parameters for the user interface are stored in memory on the CPU.
•Each AI module contains two (2) cold junction compensation (CJC) references that are factory calibrated. Factory calibration data for the CJC references is stored in a non-volatile memory on the AI module.
•Field calibration values for the AI modules (both zero offset and span calibration and CJC reference values) are stored on the CPU.
•Factory calibration values (zero offset and span corrections) for AO modules are stored in non-volatile memory on the AO module and can be changed only if the write protect jumper is not cut. See Write Protect Jumper ST1.
•The gains and offsets of the preamp are factory calibrated and the calibration data is stored in a non- volatile memory on the backplane. No field calibration of these values is possible.
Write Protect Jumper ST1
ATTENTION
A jumper (ST1) on the AO module PWA can be cut to prevent changes to calibration values. This will write protect the AO and prevent further calibration of these values.
| AI Module | CPU |
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|
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AI01 | CJC | Field | Calibration | |
| Function | |||
AI02 | Calibration | |||
CJC Factory |
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Values |
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| Calibration |
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AI03 | (AI and CJC) |
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Values | Calibration | |||
in | ||||
| CJC | User Interface | ||
AI04 |
| |||
|
|
|
AO Module
AO01
ST1
Backplane
AO02 | Factory |
| |
& Field | Factory Calibrated | ||
| |||
AO03 | Calibration | Preamp Gains and Offsets | |
Values | (for AI and CJC) | ||
| |||
AO04 |
|
|
Figure 32 Controller components that contain calibration values
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