Sourcing IS Barrier for Ultrasonic Transmitter

[PgReid]

Can anyone assist in sourcing an IS Barrier for Ultrasonic Transmitter for a 4-20mA loop powered signal?

I've contacted MTL already who state that a suitable barrier cannot be found based on the figures quoted in the instrument operation manual as follows:

Ui = 23V
Ii = 40mA
Pi = 70mW

Typical values for MTL and Pepperl and Fuchs 4-20mA barriers are:

Uo = 28V
Io = 93mA
Po = 0.65W

The control cubicle housing the barriers is under manufacturing now, so I would really appreciate a response

 

[JLSeagull]

The barrier is only applied to the 4-20 mA signal. Higher level energy is handled with explosion-proof fittings etc. I think that GE Panametrics includes intrinsic safety barriers as their preferred approach to explosion-proof ultrasonic flow meter signals. I avoid ISB's like the plague.

 

[PgReid]

Thanks JLSeagull, that's correct I'm only looking for a suitable barrier for the 4-20mA signal. The flow meter,(alrady purchased) is a siemens FUS060 with the values stated above.

 

[djs]

IS barriers for complex devices are not simple to specify. The reason being that the devices themselves can and will store energy. This means that the amount of power that can be available through the barrier must be reduced. In general the manufacturer of the device should specify the necessary limits of the IS barrier for their device.

In other words, you should contact Siemens for details on the necessary IS barrier.