PP500 LED lighting controllers - User Manual
5
General description
The PP500 current controller provides repeatable intensity control of LED
lighting for machine vision applications. It includes the power supply,
intensity control, timing and triggering functions required for machine
vision systems.
LED lighting needs a constant current supply as small variations in voltage
can cause large variations in light output. Currents can be specified in
2.5mA steps to give very fine control of intensity.
The PP500 is set up using the push buttons and the display on the front
panel of the unit (see
Section 9, Front panel configuration
).
Configurations are saved in non-volatile memory so that the PP500 will
resume operation after a power cycle.
5.1
Output modes
Three modes of operation are provided separately for each channel.
5.1.1 Continuous
In continuous mode the output is a fixed and continuous current. The
brightness can be set from 0% to 100%.
5.1.2 Pulsed
In this mode output is pulsed once per trigger. One trigger input is used to
trigger the output. The delay, pulse width and light intensity are all
configurable. In pulse mode, the brightness can be set up to 999% of its
rating, but only for short periods and low duty cycles so the lighting does
not overheat and get damaged. The default limits are as follows:
Brightness
Max pulse
width
PP500
Max duty
cycle
0 to 100%
999ms
100%
101% to
200%
30ms
30%
210% to
300%
10ms
20%
301% to
500%
2ms
10%
501% to
999%
1ms
5%
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PP500 LED lighting controllers - User Manual
5.1.3 Switched
In switched mode, you can use a trigger input to switch the output current
on and off. The output is enabled only when the input has a voltage on it.
5.2
Triggers
There are two trigger inputs, as summarised in the table below.
Mode
Trigger input
Output
Continuous
N/A
Output is on.
Switched
Trigger = 0V
Output is off.
Trigger = 3V to 24V
Output is on.
Pulsed
Trigger goes from
0V to 3V
Pulse is triggered.
Trigger goes from
3V to 0V
No action.
5.3
Flags
5.4
Automatic light sensing
When a channel does not have a light connected, the PP500 continually
tries to output a small amount of current. When a light is connected , it
flashes for a short time (the light is not damaged by this) until the PP500
detects that it is connected. You will then need to set up the current rating
of the light (see
Section 9, Front panel configuration
).
5.5
Cold start
To clear the configuration to the default settings, turn on the PP500 while
holding the
SEL
and
q
buttons for about 5 seconds, until
COL
is
displayed. Both channels are set up for 50% intensity and continuous
operation.
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