dynasonics TFXL, Installation And Operating Instructions Manual

Page: 18 / 44

18
I. CONNECTING THE PULSE OUTPUT
The TFXL is equipped with a circuit that outputs a pulse
waveform that varies proportionally with flow rate. The
quantity of pulses per unit volume of liquid is described by the
K-factor that is recorded on the side of the flow meter
enclosure. To ensure that accurate readings are being
recorded by the receiving instrument, the TFXL and the
receiving instrument must have identical K-factor values
programmed into them.
Two pulse output options are available with the TFXL:
♦
Turbine meter simulation—This option is utilized when a
receiving instrument is capable of interfacing directly with a
turbine flow meter’s magnetic pickup. The output is a
relatively low voltage AC signal that is not ground
referenced. The minimum AC amplitude is approximately
500 mV peak-to-peak. The TFXL is configured for turbine
simulation if the third character after the first dash number
in the model number is a “1”. Dip switch SW1 must be in
the off or open position.
♦
TTL pulse frequency—This option is utilized when a
receiving instrument requires that the pulse voltage level
be either of a higher potential and/or referenced to DC
ground. The output is a square-wave with a peak-to-peak
voltage swing of 5 volts. The TFXL is configured for TTL
pulse frequency if the third character after the first dash
number in the model number is a “2”. Dip switch SW1
must be in the on or closed position.