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Appendix A: Digital Input Diagrams
The following information provides descriptions and diagrams of the available I/O capabilities of the XW-ED and XW-ED-
PRO.
Digital Input
•
DIN:
The Digital I/O functions present a bit mapped image of the signals present on the corresponding
channel signal lines. The Digital I/O signal lines may be read as inputs to initiate control functions and to
activate alarms.
I/O Signal
Description
INP_1, INP_2, INP_3 Inputs may be treated as simple ON/OFF switch inputs.
Pulse Measurements
Pulse measurements include Pulse Rate (Frequency), Pulse Width, Duty Cycle, and Pulse Delay. Pulse
measurements contain the following customizable I/O signals:
I/O Signal
Description
CLK_A
Detects the positive or negative pulse edge depending on the signal type and
modifier chosen.
RST
Resets the value to 0 when active.
ENB
Enables measurement when active.
Holds the last measurement when inactive.
CLK_B (Delay only) Serves as the second signal line and is measured alongside CLK_A to determine
the Pulse Delay.
•
RATE:
The Rate (Pulse Rate Frequency) function measures the number of OFF to ON transitions in 1 second.
Rate counters may be used to measure the frequency of external signals and are often used to measure
speed/flow by coupling a magnetic transducer to a toothed wheel or impeller-based flow transducers.
•
WIDTH:
The Pulse Width function measures the time (in seconds) that the CLK (clock) signal is in the ON
state. Width timers may be used to measure the frequency of external signals and are often used to
measure speed by coupling a magnetic transducer to a toothed wheel or impeller-based flow rate
transducers.
