help triggering sleep or log out after period of HMI inactivity

Dan Gray 7 years ago in IQANdesign updated by Andy 11 months ago 7
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I'm working on an MD4 application that I would like to have automatically log out after a period of inactivity--meaning no human interaction with the MD4 touch screen. The concept would be similar to a screensaver that turns on after say 30 minutes of inactivity and requires a pin code to wake up. Is there any status code or anything else in the system that I could make use of? Would it be possible to have a System Information Channel with a Display Input Active value that is True any time the screen is being touched (ex MD4) or a button is being pushed (ex MD3)?

Thanks, Dan

One suggestion is to look at change of value on the system information channels "active display page" and "menu system open". This could be used to reset a TMR, and the value of TMR channel could be used in the reset function on a PCC.

A limitation compared to the status channel you are suggesting is that this method would not reset the timer if the user is only working in the menu system or only stays on the same display page.

The topic was posted as a private topic, would you mind if I move this to the questions or ideas section on the public forum?

For this project, the display page might not change even though the system is in use and the menu system will not be accessible without a pin code. I follow the idea though. I will look for some critical part and watch it. In my case, I can watch a motor signal or a valve solenoid signal .

Yes you can move this to a public forum. Thanks for the help.

I'm looking to do something similar, I want the backlight to dim if the display hasn't been pressed within X time. I cant think of a robust way to record every time the screen is pressed so I can measure inactivity. 2 possibilities I can think off: 1 allow overlapping buttons so I can use a large transparent button to monitor every time the screen is pressed. This currently doesn't work as it blocks the buttons behind it from registering when pressed. It also wouldn't register screen touches in the menu systems. I can monitor menus systems active but, then if they leave it on the menu it will never dim. 2 Add a new system information channel that registers every time the screen is pressed. This would be most robust as it could measure any input from any screen. 

Hey Mack

As I understand it the touch interface only works with a single button at a time. Even if you have 2 side by side that aren't overlapping and using 2 fingers you can only press one at a time. I'm sure I read something about their being an issue with using buttons for real time control of Hyd functions due to cycle times of high cpu load the master may sheds/delays some screen actions. I wonder if the single button also ensures that people don't try and use screen buttons for that .

I personally find that a PIA, especially if you want, for safety to have 2 buttons pressed. As an example, on a big engine a start button might be best if it has a confirm button that is visible only when the start button is pressed. Such an approach would make sure that each start was 100% intended, whereas a single button might lead to an accidental start when it wasn't actually intended. I can do that by adding an external confirm switch but its much more complex than adding a single on screen Virtual Digital button as a confirm function requiring both to be pressed for the intended action to occur.

However If your design has say 2 sliders and 10 buttons then add an IDC channel that looks for negativeflank activity on any of the 10 buttons, and for a change in slider value from cycle to cycle where any change makes the IDC go high. use that high to clear a counter.

.....All that said however I don't think it helps because I don't believe there's a documented programtic control over screen brightness through the System Information Channels, which if Parker provided that I imagine is where they would expose it. I am however pretty sure there is a built in screen saver functionality that exists within the MD4 menu display (I'm assuming your using and MD4 display) , open menu, go into preferences then display


The single touch issue is likely a limitation of the LCD display panel. The datasheet for the JDI display doesn't mention multi touch. 

Thanks for the info on the screen saver, I didn't know that existed. Do you know if there is a way to change the default setting to default on/dimmed?

The backlight can be controlled using a channel. There's a backlight control option under the  module display page list. Search the IQANDesign manual for "backlight" if you cant find it. 

Would also be nice if there was an option to default backlight/screen completely off. Not sure if that's technically feasible. We are trying to reduce heat generated in the module internally.


Amendment to previous post, looks like the black setting does turn the display/backlight completely off. This functionality should satisfy my use case. Still looking for information on if the default settings can be changed in the program.


Sorry, I'm only relatively new to IQAN and as such don't have the experience that some of the others here have, my knowledge on the MD4 backlight is fully used up...perhaps even overdrawn...... Gustav will probably jump in with the info you need. I did find the info you referred to in the  designer manual.... live and learn as they say.

I think the fact that you can send pretty much what ever you like over a canbus using j1939 or canopen at data rates that mean display related HMI stuff isn't likely to saturate the bus means that while you can look at a master with a built in display that's not the only solution available to you