Gardasoft Vision PP420 User manual

USER MANUAL
PP420, PP420F
LED Lighting Controllers
Revision 02
Gardasoft Vision Ltd
Castle Acres, Elsworth
Cambridge, CB23 4JQ. UK
Tel: [phone]
Fax: [phone]
Web: www.gardasoft.com

1Disclaimer
Except as prohibited by law:
All hardware, software and documentation is provided on an “as is” basis.
It is essential that the user ensures that the operation of the product is suitable for their
application.
The user must ensure that incorrect functioning of this equipment cannot cause any
dangerous situation or significant financial loss to occur.
Gardasoft Vision Ltd and Gardasoft Products Ltd will not accept any liability for
consequential loss of any kind.
All trademarks acknowledged. Hardware, software and documentation are Copyright 2002 –
2007 Gardasoft Products Ltd. Hardware manufactured by Gardasoft Vision Ltd under licence.
2Getting Started
Read the sections on Safety and Specifications and check the PP420 fulfils your requirements.
See the back cover for other Gardasoft Vision lighting controllers. Connect the PP420 up to a
power supply, Ethernet network and lights as described in Connections.
Mount the PP420 as described in “Mechanical Fixing” using a DIN rail or the mounting holes.
Read the section on Heat Dissipation. Set up the PP420 for the desired operation and test.
Download, install and run the PP420 Configuration Program from www.gardasoft.com. If you
need to use a fixed IP address set this up using the Configuration Program.
Search for the PP420 on the network and then connect to it.
On the Configuration tab, set up the current rating of the lighting and the mode of operation of
each light.
Visit www.gardasoft.com for Application Notes. There is also a Support page which has
information on troubleshooting problems.
Throughout this manual, references to the PP420 refer to all variants in the PP420 range unless
otherwise stated. The symbol “us” is used to denote microseconds.

3Safety - English
3.1.1 PP420 – Safety
Please read this before using the PP420 family of products. If in doubt, contact your distributor
or Gardasoft Vision.
Where this symbol appears in the manual, refer to the text for precautions to be taken.
3.1.2 Heat
The PP420 can get very hot. It should be positioned where personnel cannot
accidentally touch it and away from flammable materials.
Read the section on Heat Dissipation. Do not exceed the power ratings given in the manual. Note
that at the maximum ratings the case temperature can reach 80oC.
3.1.3 Electrical
The user must ensure that the potential difference between any combination of applied signals
does not exceed the supply voltage. WARNING: Higher voltages may cause a danger to personal
health.
The PP420 does not have complete tracking isolation of inputs and outputs.
Transients caused by inductive loads must be suppressed external to the PP420.
3.1.4 General
The PP420 must not be used in an application where its failure could cause a danger to personal
health or damage to other equipment.
If the equipment is used in a manner not specified by the manufacturer, the protection provided
by the equipment may be impaired.

4General Description
The PP420 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.
Three modes of operation are provided separately for each channel:
Continuous
In continuous mode the output is a continuous current.
Pulse (Strobe)
In this mode output is pulsed once per trigger. One trigger input is used as a trigger. The
delay and pulse duration can range from 20us to 1 second in 20us.
Switched
In switched mode a trigger input can be used to switch the output current on and off. The
output is only enabled when the input has a voltage on it.
Configurations are saved in non-volatile memory so that the PP420 will resume operation after a
power cycle.
The PP420 is set up using the push buttons and display on the front of the unit or using Ethernet
commands. The set up is non-volatile, so the PP420 will resume the same operation after a power
cycle.
4.1 Default Configuration
When shipped the PP420 has the following configuration:
Ethernet set to DHCP mode
Each channel set to 0.1A rating, no autosense, continuous output at 50%
4.2 Automatic Light Sensing
When a channel does not have a light connected, the PP420 continually tries to put out a very
small current. Each channel operates independently.
When a light is connected, it will flash for a short time (the light will not be damaged by this)
until the PP420 detects that it is connected.
If the AUTO_SENSE flag is set or a current rating has not been entered for this channel then the
PP420 will wait for the current rating to be set. This flag can be set using the Configuration

Program, Channel Configuration webpage or using the RR command from an application
program.
If Ethernet messages are enabled, when a light is connected and the user is being prompted to
enter the current rating, the PP420 will send one of these two messages:
Evt c,128 A light has been detected and the current rating needs to be
input
Evt c,129 A light has been detected and the current rating is not needed
Where “c” is the output channel number. An application can send an RR command back in reply,
which will cancel the user prompt.
Once the PP420 has detected the light and has a current rating for it, the light will start its
configured operating mode.
The RE Ethernet command can be used to enable/disable the current rating request. The PP420
will then use the previously entered current rating.
If the PP420 is turned off and on again, without an error occurring, then the PP420 will auto-
sense the light and assume it is the same light and so will not prompt for the current rating again.
Once an error has occurred, the user will be prompted next time a light is detected.
When a light has not been detected the following reasons can be displayed on the webpage:
Error Reason
Reset
No connect – (reason) Light not detected
Detecting Light is currently being dewtected.
Waiting for current rating The current rating needs to be entered. The light has been
detected, but the AUTO_SENSE flag is set and the controller is
waiting for the current rating to be entered.
Connected Light operating normally
Error – nn The light was operating but has been turned off due to an error
(see appendix C)
The user must press SEL to cancel the error (or send command “GR” using the Ethernet
connection) and the PP420 will then re-sense the light and ask for confirmation of the current
rating.

4.3 Output Modes
There are four trigger inputs. The sense of these signals can be active high or active low, as set
by the “P” flag.
The trigger inputs are used as follows:
Mode Trigger Input Output
Continuous Don’t care Output is on.
Switched Trigger = 0V Output is off
Trigger = 4.5V to 24V Output is on
Pulsed Trigger goes from 0V to 4.5V Pulse is
triggered
Trigger goes from 4.5V to 0V No action
4.3.1 Continuous Output and Switched Output
In continuous mode the output current is fixed and continuous. Switched mode uses a trigger
input to switch the output on or off.
In continuous and switched modes, the output current can be varied from 0% to 100% of full
brightness.
4.3.2 Pulsed Output
The output is off by default. When a trigger is the PP420 will wait for a delay and then pulse the
output. The delay, pulse width and pulse intensity are all configurable.
If the “P” flag is set triggers occur on the leading edge of the input, that is on the transition from
0V to (for example) 5V.
In pulsed mode, the brightness can be set up to 999% of its rating, but only for short periods and
at low duty cycles, so that the lighting does not overheat and get damaged. The default limits are
as follows. Other limits are available.
Output Brightness
Allowed Pulse
Width
PP420, PP420
Allowed Pulse
Width
PP420F, PP420F
Allowed Duty Cycle
0 to 100% 999ms 10ms 100%
101% to 200% 30ms 1ms 30%
201% to 300% 10ms 1ms 20%

301% to 500% 2ms 1ms 10%
501% to 999% 1ms 0.5ms 5%
So for example, if the brightness is set to 350%, then the PP420 will not allow pulses greater than
2ms long. If the trigger pulses are too close together so that the lights are on for more than 10%
of the time, the PP420 will stop the output and flag an error.
4.3.3 Current Protection
The PP420 monitors the output current and voltage and ensures it is within acceptable limits. The
RE Ethernet command can be used to disable error checking.
This is not absolute protection but does provide some safety when setting up the PP420.
4.3.4 Channel Flags
Each channel has some configuration flags.
S Flag enables or disables autosensing. When this flag is set, the PP420 will autosense - when a
light is connected for the first time, the PP420 will wait for the current rating to be entered (using
the webpage, Config program or UDP message) before continuing. When this flag is not set, the
PP420 will use the previously set current rating.
E flag enables or disables error checking. When this flag is not set, the PP420 will not detect
lighting errors.
P flag inverts the trigger signal. In pulse mode, when set the PP420 triggers from the rising edge
of the trigger. When not set, the PP420 triggers from the falling edge. The falling edge may give
a slower response time. In Switch mode, when the flag is set, the output is on when the input is
on. Clearing the P flag inverts this operation.

5Specifications
Parameter Value Notes
Digital supply
voltage (PSU+)
12V DC to
48V DC
regulated
Must be at least 1V greater than
the load potential difference at
maximum required current
Supply current
with no lights
connected
120mA This is with a 12V supply. The
current is lower at 24V.
Input enable level From 4.5V to
24V
Input disable
level <1 V
This is the voltage applied
between the positive and
negative of each trigger input
Typical trigger
input current
required
3mA at 4.5V,
22mA at 24V
Maximum output
current per
channel
2A continuous
or 10A pulsed
Ambient
temperature
during operation
5oc to 50oc
The ambient temperature may
need to be lower if the PP420 is
dissipating a lot of heat
Total allowed
power dissipation
without
heatsinking (PD)
PD=8 Watts
(max)
See Section for information on
heat dissipation

6Mechanical Fixing
The PP420 can be mounted onto a flat surface using the mounting holes in the corners, see
diagram. The PP420 should only be mounted either vertically or with its base horizontal. It
should be mounted at least 15mm away from the sides of plastic enclosures. Likewise leave a
similar space between the PP420 and any parts which could be affected by high temperatures.
The enclosure of the PP420 is used to dissipate power in the form of heat. See the
section on Heat Dissipation.
The PP420 can be mounted from above using the corner holes, or from beneath using the M4
tapped holes (maximum screw length inside is 6mm).
The PP701 kit is available for mounting the PP420 on a DIN rail.
To avoid a fire hazard consider the implications of overheating in the unlikely event of a
fault in the PP420. The power dissipation in a fault condition is approximately given by
the sum of the following for the four channels:
(<Power supply voltage> - <rated voltage for lighting>) * <max current delivered by Power supply>
Either limit the power supply output current(s) so that not more than 30W can be dissipated in
the PP420, or mount the unit in an enclosure.
To limit the power, set the power supply output voltages to the minimum value required by the
LED light and the PP420 together. Chose a PSU that limits its output current by design, by

setting the current limit on the supply (if this feature exists) or use fuses. Remember to derate the
fuse, if mounted in an enclosure, as the temperature will be higher than ambient.
The PP420 enclosure is a fire enclosure as long as the following conditions are met:
•The Ethernet connector must not be facing downwards
•The mounting holes on the underside must be covered or have a screw fitted.
If an enclosure is used, the enclosure should be metal or plastic (with a flammability rating of
UL94 V1 or better); with no holes below or to the sides of the PP420 when mounted. Cable
entries below the PP420 should be via glands that have a flammability rating as before. Observe
the specified gap between the PP420 and any other part or side of the enclosure.
The PP420 does not have an IP rating and should be mounted so that moisture and dirt cannot
enter the unit.
7Heat Dissipation
The PP420 has a linear circuit to produce the constant current output. This means that it
generates heat which needs to be dissipated.
7.1.1 Heat Output Per Channel
For a continuous output current the heat output is given by:
<heat output (W)> = <output current (A)> * ( <supply voltage (V)> - <voltage across lighting (V)> )
where:
Output current Set by the user
Supply voltage Voltage across PSU+ and PSU-
Voltage across lighting Voltage across LD1+ and LD1- (for channel 1)
This is usually easy to calculate as the voltage across the lighting is usually the voltage rating of
the light given in its specification or can be measured using a voltmeter.
For a pulsed output the heat output is given by:
<heat output (W)> = <output current (A)> * <duty cycle>
* ( <supply voltage (V)> - <voltage across lighting when pulsing (V)> )
<duty cycle> = <pulse width in seconds> * <trigger frequency in Hertz>
When overdriving, the voltage across the lighting is more difficult to find out. In most cases it is
reasonable to use the voltage rating of the light.
7.1.2 Total Heat Output
The heat output for the PP420 is given by adding the heat output for both channels, as calculated
above.
There are several ways to reduce the heat output from the PP420: