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EX1200-1538: Digital I/O and Analog Output Operation
33
D
IGITAL
I/O
AND
A
NALOG
O
UTPUT
O
PERATION
D
IGITAL
I/O
O
PERATION
In addition to its counter/timer functionality, the EX1200-1538 has sixteen independent digital
input/output (DIO) lines that can be used independent of counter operation. Each channel can
serve as either input or output.
When configured as a digital input, the logical state of the digital line is read via software. Digital
input channels are isolated, differential pairs (positive and negative). Any differential voltage
between 2.5 V and 60 V is detected as a logical High, while voltages lower than 2.5 V are treated
as logical Low. To improve noise immunity, the grounds of the digital input channels use internal
optical isolation.
+2.5 V to
+60 V
GND
The positive input channels should not be driven
low in reference to the negative channels.
External Limit Switch/
Dry Contact
+24 V Output
DIO Input Channel
DIO Input Channel
DIO_CHx_P
DIO_CHx_N
DIO_CHx_P
DIO_CHx_N
EX1200-1538
Front Panel
F
IGURE
4-1:
D
IGITAL
I
NPUT
C
HANNEL
C
ONNECTIVITY
When configured as digital outputs, the logical state of the digital lines are controlled via software.
The digital output channels use solid-state switches and are isolated from each other. Each output
channel can handle voltages up to 60 V and currents up to 50 mA. Unlike the digital inputs, the
output channels use a switch, instead of an open collector, so the polarity of the outputs do not
need to be strictly maintained, meaning that positive and negative terminals can be interchanged if
desired.
