Resetting Calibration; Table 47 Resetting Calibration Data - Honeywell ST 3000 User Manual

Resetting Calibration

Background
Every ST 3000 transmitter is factory-characterized. The characterization process calculates a mathematical
model of the performance of the transmitter's sensors and stores that data in the transmitter's memory.
Small residual errors result from the sensor data acquisition and modeling process. These errors can be
eliminated through calibration, using either a zero offset or a span correction.
A Corrects Reset returns the zero and span calibration factors to their default values. The transmitter
calculates its output based on the characterization equation alone, without any compensation for the
residual errors.
A typical zero offset correction is less than 0.1 inches of water (based on a 400 inH 2 O range) and a typical
span correction is less than 0.2% regardless of the range of calibration (down to the point where
specification turndown begins). Typical performance of a 400 inH 2 O transmitter with Corrects Reset can
be expressed as:
By calibrating the zero, the typical performance will be 0.2% or better.
For transmitter ranges other than 400", the initial zero offset will be scaled by the ratio of the Upper
Range Limit to 400. For example, for a 100 psi transmitter, the initial zero offset can be expressed by:
Please note that these are typical values, not hard specifications.
Procedure
The procedure in Table 47 shows how to reset calibration data to default values in a transmitter using the
communicator.
Step
1 Connect communicator across loop wiring and turn it on.
2 From "Online" menu, choose the following menu selections:
• Device setup
• Diag/Service
• Calibration
Reset Corrects
•
3 When prompted, remove the loop from automatic control. Press OK.
Prompt notifies you that a Reset Corrects is about to occur. Press OK.
When message "Reset Corrects OK" appears, press OK.
Previous calibration "CORRECTS" are removed and calibration is reset to default values.
4 When prompted, return the loop to automatic control and press OK.
10/05
Accuracy = 0.2% + (0.1"/span") • 100%
0.1" • 2768/400 = 0.7" or 0.025 psi.

Table 47 Resetting Calibration Data

ST 3000 HART Transmitter Release 300 User Manual
10— Calibration - Resetting Calibration
Action
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