Under review

Parameter value jumps after enabling Funtion Group

Edzard 2 weeks ago in IQANdesign • updated 2 weeks ago 2

I have found a problem with using parameter channels in combination with the enable of Function Groups.

The problem occurs when I want to adjust a parameter channel which is in a disabled Function Group. When I try to adjust the slider,  it jumps back to its old value upon release. So far, so good. But when I enable the Function Group, the slider jumps to the place where I released it last.

This means an unauthorized person can adjust all sliders and the values will be copied after login.

I tested this in simulation with IQAN Design 5.04 and a MD4-10" display.

Under review

Thanks. I can confirm that this is how the MD4 display controls for adjust items (the slider/switch and state picker) works. 

If you set a PIN code or access level on the adjust group, then IQANdesign will warn you about Adjust item protection overridden. 

But if you disable the channel (or the adjust item), then there is no warning in IQANdesign, and the behavior can be quite confusing. I agree that this should be changed/fixed.  

The best way for protecting the adjust items is to only use the menu system adjust groups, where you can set a PIN code (MD4) or  access level (IQANrun). 

If you use the MD4 display controls for parameters that the operator shouldn't have access to, then a workaround could be to work with the visibility property of the display controls. 


Thank you for investigating this problem. I have also solved it using the visibility setting. So for me it is OK now. 

This is however an easily made mistake, that can have strange consequences, so I'm looking forward to the fix.