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4.11.11. How to set the detailed setting
Description
The data required for time difference measurement can be set as follows.
This parameter is intended for our service personnel.
Do not change the setting by yourself. Otherwise measurement may be disabled.
Make the detailed setting only when a problem should arise in flow rate measurement with factory default settings, and
instructed to do so by a trained factory representative. Setting need not be made in other cases.
Setting items
Item Input method Function, range or menu
Transmission
count
Select
The number of transmission of ultrasonic signals per flow rate signal output
*1
. (Factory-set
value: 128)
When standard mode is selected for the operation mode:
8, 16, 32, 64, 128, 256
When high speed response mode is selected for the operation mode:
4, 8, 16, 32, 64, 128
Trigger control
Select
Numeric value
Control method setting of the trigger level (detection point) of ultrasonic signals. (Factory-set
value: AUTO)
AUTO
MANUAL
Select the detection point according to the rate against the peak of receiving wave
regarded as 100%.
Trigger level: 10% to 90%.
Window control
Select
Numeric value
Numeric value
Setting of control method of measurement window that takes in signals (Factory-set value:
AUTO)
AUTO
MANUAL
Set the time of starting taking in signals (period from the start of transmission until the
startup of window signals)
U: open time: 1μs to 16383μs
D: open time: 1μs to 16383μs
Note) U: forward direction, D: reverse direction
In case of MANUAL, set U and D.
Saturation (level)
Numeric value
The number of times that the amplitude of received signals fluctuates and exceeds ±1.0V
(saturation) per 1 flow rate signal output. Used as the threshold value for judging the error
status of signals. A signal error occurs if the specified number of times is exceeded.
(Factory-set value: 128) Refer to diagram *1) in the next page.
0 to 256
Measurement
method
Select
Setting of measurement method for measuring transit time. (Factory-set value: method 2)
Method 1: Strong against interference
Method 2: Controls triggers on the plus side of the direction of voltage of received signals.
Method 3: Controls triggers on the minus side of the direction of voltage of received
signals.
Signal balance
Numeric value
Setting of threshold value used for judging the existence of transit time. A signal error occurs
if the specified value is exceeded. (Factory-set value: 25%)
0% to 100%
Note) Set to 50% or higher for Method 1.
Transmission
pattern
Select
Setting of transmission pattern of ultrasonic signals (Factory-set value: Burst 3)
Select from BURST 1, BURST 2, BURST 3, BURST 4, BURST 5, CHIRP 4 and CHIRP 8.
AGC gain
Select
Numeric value
Numeric value
Setting of control method of signal AGC gain (Factory-set value: AUTO)
Signal peak is controlled to be kept at 1.5V
PP
.
AUTO
MANUAL
Make the setting so that the signal peak in both forward and reverse directions is kept at
1.5V
PP
.
Forward gain: 1.00% to 99.00%
Reverse gain: 1.00% to 99.00%
Signal peak
Select
Setting of signal peak threshold value per 1 flow rate signal output *1). Used as the
threshold value for judging the error status of signals. A signal error occurs if the value
becomes lower than the specified value. (Factory-set value: 3072)
0.5V(4096) : Equivalent to 0.5V
0P
0.375V(3072) : Equivalent to 0.375V
0P
0.25V(2048) : Equivalent to 0.25V
0P
0.125V(1024) : Equivalent to 0.125V
0P
Transmission
wait time
Numeric value Transmission interval of ultrasonic signals. (Factory-set value: 5msec)
5msec to 30msec
For actual keying, refer to the typical operation indicated below. Set the protection to OFF beforehand. (See Section 4.4.1.)
CAUTION
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