GE XGS868 Programming Manual page 24

Transducer
Signal
Parameters Range
-1000 to
Delta T Offset
1000 msec
–500 to
Skan T Offset
500 msec
% of Peak 1 to 100%
Xmit Sample 2, 4, 8, 16
Size or 32
0 to 250
M>S Switch
msec
# Shifts 0 to 10
A Divisor 0.1 to 10
# Transmit
1 to 16
Pulses
T Window
0 to 1000
(cycles)
R Window
10 to 128
(cycles)
Programming Site Data
Table 1-4: Transducer Signal Settings
Default
Value
An offset between the upstream and downstream transit
0 msec
times is specified at this prompt.
At this prompt, specify a time measurement offset that
58 msec
compensates for a shift resulting from cross-correlation.
The percentage of peak used to calculate the transit times
50%
and Delta T is specified at this prompt.
Both the upstream and downstream transducers transmit
ultrasonic pulses in bursts, which consist of a series of
8
transmit pulses. XMIT SAMPLE SIZE determines how many
bursts are sent in one direction before sending in the other
direction.
If the burst mode is set to Skan/Measure (S/M), the meter
switches from Skan to Measure Mode when Delta T is less
50 msec
than the M>S_Switch value. DO NOT change this value
unless advised by the factory.
The number of shifts corresponds to the actual number of
transmits per cycle (number of signals added together in
3 one direction to produce an averaged signal for one
interrogation of the fluid) and need only be changed if the
environment is very noisy or the acoustic signal is weak.
The Divisor used to calculate the Measure Mode
2.5
integrated threshold level is not normally changed.
# Transmit Pulses specifies the number of pulses in a
burst. For difficult conditions (i.e. long paths, high velocity
4
or high temperature), settings as high as 16 may be
necessary.
The XGS868 calculates the size of the transmit window
based on pipe size and fluid sound speed. However, for
0
special diagnostic purposes, it is possible to reset the
window size.
The XGS868 calculates the size of the receive window
based on pipe size and fluid soundspeed. However, for
10
special diagnostic purposes, it is possible to reset the
window size.
Miscellaneous Information
November 2004
1-17