Dynasonics DXN Portable Ultrasonic Measurement System - Manual (Page 83)

External
Pull-Up
Resistor
33 mS
0
+V
Totalizing Pulse - 33 mS Duration
0
+V
On Off
Rate pulse - 1 KHz Maximum
On Time = Off Time
Figure 114: Digital Output Internal Power
Rate Pulse Scaling
The rate pulse has a maximum frequency of 1,000 Hz which is proportional to the minimum and maximum user flow rates
entered. Setting the minimum and maximum flow rates is accomplished using the Meter>Limit software controls.
For example, if the minimum flow rate were set to –100 gpm and the maximum flow rate was +100 gpm the 1000 Hz output
would span the distance from –100…100 gpm.
In this example the output frequency would then be interpreted as follows:
0 Hz = –100 gpm
250 Hz = –50 gpm
500 Hz = 0 gpm
750 Hz = +50 gpm
1000 Hz = +100 gpm
The maximum current capacity for the transistor is 100 mA with a maximum supply voltage of 10 V DC. These parameters
require the pull-up resistor to at least a minimum of 1000 ohms.
In rate pulse output mode, the transistor has a duty cycle of 50%.
Totalizing Pulse
When used to transmit a totalizing pulse the digital output sends a fixed width (33 mS) pulse that follows the display totalizer.
For each increment of the totalizer the digital output will send 1 pulse. The duration of the pulse will be 33 mS with an
amplitude approximately equal to the level of +V. See Meter>Totalizer to set totalizer parameters.
NOTE: N
The totalizing pulse output is for positive going flow only. Under reverse flow conditions the totalizer will neither
increment or decrement.
Installation & Operation Manual
Page 83 February 2013