3.4.3
Modifying the calibration parameters for T-200
transducers
When T-200 transducer pairs, housings or stalks are replaced, the corresponding meter
calibration parameters must be updated for accurate operation. This means modifying the
affected chord "L" dimension (
LA... LD
) (see Determining the “L” Value below), average
delay time (
AvgDlyA... AvgDlyD
) and delta delay time (
DltDlyA... DltDlyD
) using the
MeterLink Transducer Swap-out Wizard (see
).
Generally, there are three types of situations that require updating delay times or both
delay times and length "L":
•
Replacing T-200 transducer capsules only
: need to update delta delay time only. No
change in length "L".
•
Replacing T-200 transducer capsules and housings
: need to update average and delta
delay times, and length "L".
•
Replacing full T-200 transducer assemblies, including capsules, housings and stalks
: need
to update average and delta delay times, and length "L".
Procedure
1. Update average delay time and delta delay time. The transducer pair average delay
time and delta delay time are located on the transducer pair calibration sheet.
These values must be downloaded to the appropriate meter data points (
AvgDlyA...
AvgDlyD, DltDlyA... DltDlyD
).
2. Update the chord lengths "L" of the transducers. The lengths of transducer assembly
and individual components, including housing, spacer and stalk, are included on the
calibration sheet and are etched on the transducer housings, spacers and stalks.
The length of the meter body is found on the original calibration sheet supplied
with the meter. The value "L" is determined by subtracting the lengths of the
transducer stalks, spacers and housings from the length of the meter body. This
value should be written to the appropriate meter data points for each chord that
received new transducer housings and/or transducer stalks (
LA... LD
).
3. Chord length “L” Calculation. The chord length “L” is calculated from the meter
length as well as the lengths of transducer stalks, spacers and housings as shown in
the following equation.
Equation 3-2: Chord "L" Dimension for T-200 transducer assemblies
L
cℎord
= L
MeterHousing
− L
Stalk1
− L
Spacer1
− L
Housing1
− L
Stalk2
− L
Spacer2
− L
Housing2
where
L
chord
= chord “L” dimension (in) (
LA…LD
)
L
MeterHousing
= meter housing length (in)
L
Stalk1
= transducer 1 stalk length (in)
L
Stalk2
= transducer 2 stalk length (in)
L
Spacer1
= transducer 1spacer length (in)
L
Spacer2
= transducer 2 spacer length (in)
Meter repairs
Maintenance and Troubleshooting Manual
April 2022
00809-0600-3104
62
Emerson.com/Rosemount
