Electronics Assembly; Ez Cal Option - ABB Platinum standard Series Product Instruction

Electronics Assembly

EZ CAL Option

WBPEEUI110504A0
A welded housing protects the cell from the surroundings. The
cell used for measuring absolute pressure has a vacuum
sealed reference chamber.
The pressure, transmitted by the isolating diaphragms and fill
fluid (silicone oil or fluorinated oil), moves the measuring dia-
phragm. An AC voltage excites the two series coils. The mid-
point voltage of these coils varies as a function of the
movement of the magnetic cores welded to the measuring
diaphragm.
The cell and characterization board are a matched set and may
not be separated. For more information on the characteriza-
tion board, refer to Electronics
Figure 2-3 shows the Type PTSD pressure transmitter elec-
tronics in block diagram form. All calibration, configuration,
and compensation data are stored in both the main and char-
acterization boards. The output of the cell goes into a custom
analog to digital converter on the LSI smart chip via the char-
acterization board. The microcontroller requests the digital
outputs of the custom analog to digital converter. It uses these
digital outputs and the memory stored on the characterization
board to calculate an output for the transmitter. This output is
then available as a four to 20-milliampere output or a polled
digital process variable signal.
The transmitters include a lockout jumper that when acti-
vated, prevents any
configuration (Fig. 5-1).
NOTE: The EZ CAL option is for zero and span validation only. Do
not use it to change the calibrated span of the transmitter. The
EZ CAL option provides no means to indicate if an error is made.
After mounting the EZ CAL option, one of two magnetically
coupled components responds to the moving of a magnet in
the EZ CAL option. When validating the zero, adjust the input
pressure to the configured zero value and turn and hold the
adjustment screw on the EZ CAL option in the zero direction
for at least three seconds. This causes the electronics to auto-
matically adjust the output to zero percent. To validate the
span, set the input pressure to the configured span value,
depress the span lock and turn and hold the adjustment screw
on the EZ CAL option in the span direction for at least
three seconds. This causes the electronics to automatically
adjust the output to 100 percent. Span or zero or both may be
adjusted.
DESCRIPTION AND OPERATION
Assembly.
alterations to the calibration
FUNCTIONAL OPERATION
or
2 - 3