Dynasonics TFXL Clamp-On Ultrasonic Flow - Manual (Page 17)

06-TTM-UM-00158 8/2012 17
200
100
300
400
500
600
700
800
900
1000
1100
10 12 14 16 18 20 22 24 26 28
Supply Voltage (VDC)
L
o
op L
oad (
O
h
m
s)
Operate in the
Shaded Regions
Supply Voltage - 7 VDC
0.02
= Maximum Loop Resistance
FIGURE 3.1 - ALLOWABLE LOOP RESISTANCE
4-20 mA Return (-)
4-20 mA Output (+)
4-20 mA Ground
4-20 mA Output
FIGURE 3.2 - 4-20 MA OUTPUT
The 4-20 mA output signal is available between the 4-20 mA
Out and Signal Gnd terminals as shown in Figure 3.2.
BATCH/TOTALIZER OUTPUT FOR TFXL
Totalizer mode confi gures the output to send a 33 mSec
pulse each time the display totalizer increments divided by
the TOT MULT. The TOT MULT value must be a whole, posi-
tive, numerical value.
For example, if the totalizer exponent (TOTL E) is set to E0
(×1) and the totalizer multiplier (TOT MULT) is set to 1, then
the output will pulse each time the totalizer increments one
count, or each single, whole measurement unit totalized.
If the totalizer exponent (TOTL E) is set to E2 (×100) and the
totalizer multiplier (TOT MULT) is set to 1, then the control
output will pulse each time the display totalizer increments
or once per 100 measurement units totalized.
If the totalizer exponent (TOTL E) is set to E0 (×1) and
the totalizer multiplier (TOT MULT) is set to 2, the control
output will pulse once for every two counts that the totalizer
increments.
TOTALIZER OUTPUT OPTION FOR TFXL
TFXL units can be ordered with a totalizer pulse output op-
tion. This option is installed in the position where the rate
pulse would normally be installed.
OPTIONAL TOTALIZING PULSE SPECIFICATIONS
OPTIONAL TFXL TOTALIZING PULSE OUTPUT
Signal
1 pulse for each increment of the totalizers least
signifi cant digit.
Operation
Normal state - high; pulses low with display total
increments
Pulse
Duration
30mSec minute
Source/
sink
2 mA maximum
Logic 5 VDC
Wiring and confi guration of this option is similar to the total-
izing pulse output for the TFXL variation. This option must
use an external current limiting resistor.
TTL Pluse (+)
TTL Pluse (-) TTL Pluse (+)
TTL Pluse (-)
O N 1
FIGURE 3.3 - TFXL TOTALIZER OUTPUT OPTION
FREQUENCY OUTPUT
The frequency output is a TTL circuit that outputs a pulse
waveform that varies proportionally with fl ow rate. This type
of frequency output is also know as a “Rate Pulse” output. The
output spans from 0 Hz, normally at zero fl ow rate to 1,000
Hz at full fl ow rate (confi guration of the MAX RATE param-
eter is described in detail in the fl ow meter confi guration
section of this manual).
Turbine Simulation
Turbine Output
Turbine Output
O N 1
FIGURE 3.4 - FREQUENCY OUTPUT SWITCH SETTINGS
The frequency output is proportional to the maximum fl ow
rate entered into the meter. The maximum output frequency
is 1,000 Hz.
If, for example, the MAX RATE parameter was set to 400 GPM
then an output frequency of 500 Hz (half of the full scale
frequency of 1,000 Hz) would represent 200 GPM.
In addition to the control outputs, the frequency output can
be used to provide total information by use of a “K-factor”.
A K-factor simply relates the number of pulses from the
frequency output to the number of accumulated pulses that
equates to a specifi c volume.