Omron CRT1 - 10-2009, Operation Manual

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Functions of Digital I/O Slave Units
Section 11-3
4. Click the Close Button. The window will close.
11-3-8 Load Short-circuit Detection (Outputs)
Description
This function monitors the load current in the output section and detects a
load short-circuit if the current per contact (or common) exceeds a rated
value. If a load short-circuited is detected, the outputs are turned OFF to pre-
vent damage to the Unit output circuits. Load short-circuit detection functions
in two different ways depending on Unit specifications. For some Units, the
outputs are turned OFF for the entire Unit if a short-circuit is detected for even
one output. For other Units, the outputs are turned OFF individually. For infor-
mation on load short-circuit detection, refer to the rated output current and
internal circuits in the specifications for the applicable Unit.
An indicator on the Slave Unit can be used to see if a load short-circuit has
been detected. Also, if a short-circuit has been detected, an internal status bit
will turn ON in the Slave Unit to inform the Master Unit. The current status can
be read using the CX-Integrator or an explicit message. Once the cause of the
short-circuit has been removed, operation will recover automatically and
power will be output to the connector where the short-circuit was detected.
Note An OMRON S82J-series Power Supply device is recommended for the I/O
power supply. Load short-circuits may not be detected if a power supply with
vertical-drop overcurrent protection characteristics is used. If a power supply
Short-circuit
Output forced OFF
Load
Is the load short-circuited?