Omron CRT1 - 10-2009, Operation Manual

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Functions of Digital I/O Slave Units
Section 11-3
11-3-7 Power Supply Short-circuit Detection (Inputs)
Description
This function monitors the current in the sensor power supply section and
detects a power supply short-circuit if the current per input contact exceeds a
rated value. Power supply short-circuit detection functions in two different
ways depending on Unit specifications. For some Units, the I/O power supply
is turned OFF to the entire Unit if a short-circuit is detected for even one input.
For other Units, the I/O power is turned OFF individually for each input.
For information on load short-circuit detection, refer to the power short-circuit
protection and input device power supply specifications for the applicable
Unit.
An indicator on the Slave Unit can be used to see if a power supply short-cir-
cuit 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 automati-
cally and power will be output to the connector where the short-circuit was
detected.
Note Use a power supply device with a rating of 100 W or higher as the communi-
cations power supply for network power supply. A short-circuit is detected if a
current that exceeds a specified value flows in the sensor power supply output
of the Unit. Also, the communications power supply may temporarily turn OFF
when a short circuit occurs. Operation will automatically be restored once the
cause of the short circuit has been removed, but implement an external circuit
so that the system operates safely while the outputs are turned OFF. Use the
following formula as a guide for Sensor communications power supply capac-
ity.
• Total network current = Total Unit current consu Total Sensor cur-
rent consumption
• Communications power supply capacity used
≥
(Total network c
(Short-circuit detection current))
×
(CompoNet network voltage used)
Monitoring Status
with the CX-Integrator
1,2,3... 1. Turn ON the power supply to the CompoNet Slave Unit.
2. Go online, right-click the icon of the applicable CompoNet Slave Unit in the
Network Configuration Window, and select
Monitor .
3. Make sure that the Sensor Power Supply Short-circuit Check Box is select-
ed.
Short-circuit
Sensor
Is the sensor power supply short-circuited?