PL-U enclosed cameras with a Machine Vision interface provide hardware Trigger and GPIO capability. The mating connector is an 8-pin Hirose HR25A-7P-8P cable plug with solder pins for 28 AWG wires. The connector pinout is shown below (not-to-scale for clarity of pin numbers).
Pin Assignment
| Pin | Wire Color | Pin Name | Function | Comments |
|---|---|---|---|---|
1 | Red | VBUS | 3.3V or 5.0V power output | GPIO2 must be enabled as either 3.3V or 5.0V. The maximum current available from this output pin is 100mA. |
2 | Violet | TRIGGER+ or GPI+ | Positive terminal of optically isolated trigger input or General Purpose Input. | See trigger or GPI notes below chart. |
3 | Brown | TRIGGER- or GPIO- | Negative terminal of optically isolated trigger input or General Purpose Input or Output. | See trigger or GPI notes below chart. |
4 | Yellow | GPO1+ | Positive terminal of optically isolated General Purpose Output 1. | Optical isolator open collector output. Provides current sink to pin 3 when GPO1 is active. Maximum 15 mA. Maximum 40 V. |
5 | Green | GPIO2 | HCMOS General Purpose Input / Output 2 | The maximum HCMOS output current is 5mA |
6 | Orange | GPIO3 | HCMOS General Purpose Input / Output 3 | The maximum HCMOS output current is 5mA |
7 | Blue | GPIO3 | HCMOS General Purpose Input / Output 4 | The maximum HCMOS output current is 5mA |
8 | Black | GROUND | Logic ground. | Logic ground is internally connected to the camera metal enclosure. |
Trigger Notes
To initiate a trigger, apply a voltage between 5V and 12V (4-11mA) to the optically isolated trigger input terminals.
The optically isolated trigger input includes an internal 1K ohm series resistor.
When using a trigger voltage larger than 12V, add an external series resistor with an adequate power rating.
Debounce delay is set in the camera to 1 microsecond.
Trigger pulse duration must be at least 300 us, otherwise trigger pulses might be ignored.
A typical application of the trigger input is to connect Pin 1 (POWER) to Pin 2 (TRIGGER+), and then use the open collector output of an external position sensor device to complete the circuit from Pin 3 (TRIGGER–) to Pin 8 (GROUND). Note: This setup requires GPIO2 to be enabled as 5.0V power output.
Only one of the 4 potential hardware trigger lines can be used as the hardware trigger source at a given time, and setting the line as hardware trigger will prevent you from using that line as GPIO.
If the user chooses to use the first GPIO (GPIO#1) as the hardware trigger, then the hardware trigger must be optically isolated. Otherwise, it will use CMOS input as the trigger.
GPIO#1 cannot be used simultaneously as Input, and Hardware1 as a Trigger Type.
Trigger Polarity
The trigger polarity can be set to Positive or Negative. (See the Triggers and GPO Tab - Pixelink Capture or External Control Tab - Capture OEM)
With the trigger polarity set to Positive, a camera will trigger on the rising edge of the trigger signal.
With the trigger polarity set to Negative, a camera will trigger on the falling edge of the trigger signal.
GPI Notes
Review the trigger notes above for electrical characteristics of the GPI.
For Trigger and GPI implementation, review the Trigger and the General Purpose Input Output articles respectively.