VC20XX_HW.pdf – Hardware Documentation VC20XX Smart Cameras
11
4 PLC I/O Signals
The camera has four optically decoupled inputs and four decoupled outputs for controlling machines
and processes.
An I/O processor is responsible for the handling of the PLC I/O signals.
The PLC-compatible inputs (24-V level, the positive signal is connected) include input protection
circuits. A minimum voltage of 14V is required to reliably sense a logic high signal.
The PLC outputs feature a highly integrated MOSFET, high-side switch with built-in protection . It is
possible to switch inductive or capacitive loads. The protective feature of the outputs will produce
pulses on the outputs, if the limiting values are exceeded.
A protective diode ensures, the poles of the supply voltage from the power supply of the PLC can not
be swapped. It is important to connect both the external supply voltage of the outputs (+24V) as well
as GND (GNDIn) of the power supply of the PLC.
The complete circuitry, including the I/O processor, is galvanically separated from the rest of the
camera electronics.
If DC failure of the PLC power is detected, this information is forwarded to the DSP (PLC power failure
interrupt)
Output drivers feature short circuit end thermal overload protection
For additional protection of the output drivers, the I/O processor monitors the total PLC current, and
switches off all outputs if the maximum threshold value is exceeded.
Technical data of the I/O signals:
Trigger input and trigger output
4.1 Input Signals
Nominal voltage:
24 V +/- 20%
Absolute maximum voltage:
voltages greater than 40 V can destroy the inputs
Type:
galvanically separated by optocoupler (PLC
communication interface)
Input current:
1 mA @ 24V
Threshold value:
14 V
Internal signal delay:
100 µsec (signal) + 0..200 µsec (polling) + DSP interrupt
latency
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1996-2005 Vision Components GmbH Ettlingen, Germany
