PA uses MBP-IS technology, where both power and communication signal are sent down the same single-twisted pair wire. The MBP stands for Manchester-encoded Bus Powered, the IS stands for “Intrinsically Safe”. The Power transmission and Communication are both acheivable with slip ring technology. There are many slip ring manufacturers that can provide products that can do that. Intrinsically Safe or “ex” is the difficult part. I do not know of any slip ring vendors that claim IS. Moving wire brushes for transfer of power can cause a problem for an IS environment. Sparks as a possible source of ignition are not ok.
So your answer is Yes for non-Intrinsically Safe environments and No for IS.
If the power is being supplied from a Siemens DP/PA device (Cl 1 Div 2) – is it not limited/protected so that not enough energy is supplied to permit a spark from occurring anyway. Same as is someone shorts the cable wires?
George, You have a good point.
If the power of the source is limited, then there should be no way a device can cause a problem. But, if that is the case, why do we have ex rated and non-ex rated versions of the same devices that will be downstream from the coupler? I know that intruments and passive components like AFDs and junction boxes all have ex and non-ex versions. I will not recommend a non-rated component for an IS system. I am not a safety engineer.
Anyway, we have exhausted my nickel’s worth of knowledge on Intrinsically Safe slip rings.
I’m looking forward to see if anyone else has any thoughts on this.