Installation and Configuration
Npaq MR Hardware Manual
2.5.3. Opto-Isolated Outputs
The digital outputs are driven by optically-isolated solid state relays and may be connected in sourcing or
sinking configurations. The digital outputs are designed to connect to other ground referenced circuits and
are not intended to provide high-voltage isolation.
The outputs are software-configurable and must be connected in either all sinking or all sourcing mode.
and
illustrate how to connect to an output in current sourcing and current sinking
modes, respectively.
The opto-isolator's common connections can be directly connected to the drive's power supply; however,
doing so will effectively defeat the isolation and will reduce noise immunity.
N O T E :
Power supply connections must always be made to both the Output Common Plus (OP) and
Output Common Minus (OM) pins as shown in
and
Table 2-24:
Opto-Isolated Output Connector Pin Assignment
Pin#
Description
In/Out/Bi
9
Output
Input
10
Optically-Isolated Output 0
Output
11
Optically-Isolated Output 1
Output
12
Optically-Isolated Output 2
Output
13
Optically-Isolated Output 3
Output
21
Output Common -
Input
22
Optically-Isolated Output 4
Output
23
Optically-Isolated Output 5
Output
24
Optically-Isolated Output 6
Output
25
Optically-Isolated Output 7
Output
Table 2-25:
Output Specifications
Opto Device Specifications
Value
Maximum Voltage
24 V maximum
Maximum Sink/Source Current
80 mA/channel @ 20°C; 60 mA/channel @ 50°C
Output Saturation Voltage
2.75 V at maximum current
Output Resistance
33 Ω
Rise / Fall Time
250 usec (typical)
Maximum Output Frequency
1 kHz
Suppression diodes must be installed on outputs driving relays or other inductive devices. This protects the
outputs from damage caused by inductive spikes. Suppressor diodes, such as the 1N914, can be installed
on all outputs to provide protection. It is important that the diode be installed correctly (normally reversed
biased). Refer to
for an example of a current sinking output with diode suppression and
for an example of a current sourcing output with diode suppression.
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Chapter 2
41
