Universal Robots Forum

Problem with tool digital outputs after turning on any program

Hi. For my bachelor thesis I’ve created my own tool control board which reads signals from digital outputs pins from the tool socket and performs proper action based on states of these signals. Project works pretty well when I use teachpendant with Installation settings shown in image1.jpg and manually toggle tool digital output 0 or 1 - I can see that LEDs are blinking, and I can “read” this signal using Arduino(check schema below). Problem occurs when I start any program(doesnt matter if its external control ROS based program, or simple move up and down made via teachpendant) - LEDs shut down and my circuit doesnt receive any signal(f.e. when I want to set tool digital output state). Even after program stops - I cant manually turn them on. What I need to do is go to installation tab, io settings(like in image1) and toggle voltage 24V->12V->24V and same for digital output mode: sourcing → sinking → sourcing. Then I can again read these signals, LEDs are blinking etc.

Right now I am out of ideas what could go wrong. Thanks for help in advance.