2.6.1. Digital Outputs
Optically-isolated solid-state relays drive the digital outputs. You can connect the digital outputs in
current sourcing or current sinking mode but you must connect all four outputs in the same
configuration. Refer to
and
.
You must install suppression diodes on digital outputs that drive relays or other inductive devices. To see
an example of a current sourcing output that has diode suppression, refer to
. To see an
example of a current sinking output that has diode suppression, refer to
The digital outputs are not designed for high-voltage isolation applications and they should only be used
with ground-referenced circuits.
The digital outputs have overload protection. They will resume normal operation when the overload is
removed.
Table 2-25:
Digital Output Specifications
Digital Output Specifications
Value
Maximum Voltage
24 V (26 V Maximum)
Maximum Sink/Source Current
50 mA/output
Output Saturation Voltage
0.2 V at maximum current
Output Resistance
4 Ω
Rise / Fall Time
250 µs (2K pull up to 24V)
Reset State
Output Off (High Impedance State)
Table 2-26:
Digital Output Pins on the Digital/Analog I/O A Connector
Pin #
Label
Description
In/Out/Bi
1
DO0
Digital Output 0 (Optically-Isolated)
Output
2
DO1
Digital Output 1 (Optically-Isolated)
Output
3
DO2
Digital Output 2 (Optically-Isolated)
Output
4
DO3
Digital Output 3 (Optically-Isolated)
Output
5
DOC
Digital Output Common
Input
GL4 Hardware Manual
2.6.1. Digital Outputs
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