AB 1790D "Protected" outputs

Hello All. The digital outputs of the 1790D range of remote i/o devices from AB are described as "protected", but that's all; just a description. No one at R.A. has a clue regarding the permitted duration of a short circuit on an output and the pdfs just show a box labelled "protected output device". Does anyone here have inside knowledge or know of a pdf that gives this information? Thanks.

I believe that this is referring to the following:
To comply with the CE Low Voltage Directive (LVD), the DeviceNet network and outputs must be powered from a source compliant with Safety Extra Low Voltage (SELV) or Protected Extra Low Voltage (PELV). To comply with UL restrictions, the DeviceNet network must be powered from a source compliant with Class 2 or Limited Voltage/Current.

https://en.wikipedia.org/wiki/Extra-low_voltage

Hope this helps,
Garry
http://www.accautomation.ca