Panametrics DigitalFlow DF868 - Page 32

Chapter 1. Programming Site Data
22 DigitalFlow™ DF868 Multipurpose Ultrasonic Liquid Flowmeter Programming Manual (2-Channel)
Transit-Time SIGNAL Options (cont.)
9. Press [ENT] to accept the current Amp. Discrim High value or enter a new value and press [ENT].
The amplitude discriminator measures the size of the transducer signal received by the Model DF868. The default
value for this parameter is 34 and values from 0 to 100 are acceptable. The E5: AMPLITUDE error message appears
when the amplitude discriminator exceeds the programmed AMP. DISCRIM HIGH value. See the Service Manual for a
discussion of error codes.
10. Press [ENT] to accept the current Delta T Offset value or enter a new value and press [ENT].
An offset between the upstream and downstream transit times is specified at this prompt. The default value for this
parameter is 0 sec and values from –1000 to 1000 sec are acceptable.
11. Press [ENT] to accept the current % of Peak value or enter a new value and press [ENT].
The percentage of peak used to calculate the transit times and Delta T is specified at this prompt. The default value
for this parameter is 50% and values from -100% to 100% are acceptable.
12. Use the [
 and [F1]-[F4] keys to select one of the preset values for the XMIT Sample Size from the option bar.
Both the upstream and downstream transducers transmit ultrasonic pulses in bursts, which consist of a series of
transmit pulses. XMIT SAMPLE SIZE determines how many bursts are sent in one direction before sending in the other
direction. The default value for this parameter is 8 and values of 2, 4, 8, 16 and 32 are acceptable.
13. Press [ENT] to accept the current # of Errors value or enter a new value (0 to 16) and press [ENT].
Use this prompt to enter the number of errors the DF868 can record before it displays an error message. The default
value is 6.
14. Press [ENT] to accept the current Minimum Peak % Limit value or enter a new value and press [ENT].
Use this prompt to enter the minimum percent of peak that the DF868 can use to measure transit time. The DF868
accepts values from -100 to +100.
15. Press [ENT] to accept the current Maximum Peak % Limit or enter a new value and press [ENT].
Use this prompt to enter the maximum percent of peak that the DF868 can use to measure transit time. The DF868
accepts values from -100 to +100.
16. Press [ENT] to accept the current T Window (Cycles) value or enter a new value and press [ENT].
Normally, the Model DF868 calculates the size of the transmit window based on pipe size and fluid sound speed.
However, for special diagnostic purposes, it may sometimes be necessary to reset the window size. The default value
for this parameter is 0 and values from 0 to 1000 are acceptable.
17. Press [ENT] to accept the current R Window (Cycles) value or enter a new value and press [ENT].
Normally, the Model DF868 calculates the size of the receive window based on pipe size and fluid sound speed.
However, for special diagnostic purposes, it may sometimes be necessary to reset the window size. The default value
for this parameter is 10 and values from 10 to 128 are acceptable.