Galvanic Isolator or Zener barrier

A

Thread Starter

Abu

i want to understand
1. what is the basic different between them?

2. is there any guidelines we have to follow isolator or barrier?

3. Can we able to use barrier in place of isolator

4. Can anyone please provide me a detail earthing diagram of them? I have seen that barrier is loop powered while isolator needs separate power supply

Thanks
abu
 
R
Barriers are usually used in Intrinsic Safe wiring, there is a direct electrical connection between the input and output terminals. In other words they don't isolate the signal just limit the power that can flow from a safe area to the hazardous area.

Isolators are normally used where you need to isolate one part of the loop from another for example if they are at a different potential.

Special isolators are required for Intrinsic safe wiring. again to limit the power available in the hazardous zone. Some isolators are also loop powered.

Give us some more details on what you are trying to do and you will get a better answer.

Regards
Roy
 
Isolators or transformer isolated barriers do not require a Intrensically Safe (IS) ground while zener barriers require a IS ground.

Zener barriers are in the way out..suggest isolators

Srini
 
I think your question should have been the difference between Isolated barrier and zener barrier.

Zener barriers are used in Intrinsically Safe (IS) loops for hazardous area application. Isolators are normally used in non-hazardous area two provide one or more than one output from a single input. Inputs and outputs are isolated - that's why the name.

Isolated barriers are one kind of isolators which are used in hazardous area and does the same function like a zener barrier. There are many advantages for using Isolated barriers e.g.

1. Zener barriers need separate IS earth. No IS earth is required for Isolated barriers;

2. For zener barriers you need to be careful about the complete loop resistance including barrier resistance. For isolated barriers overall load resistance calculation is very easy and normally can drive higher load resistance than zener barrier;

3. For zener barrier you must be very careful about the ground loop problems. If the input transmitters or output indicator/controller do not have isolated circuits or common ground, you may end up in complex ground loop problems. Isolated barriers are free from such ground loop problems;

4. Isolated barriers are 4-wire device, but again this doesn't make any difference since the device will be installed in the panel and separate power supply is not a problem;

5. Zener barriers are less costly than isolated barriers

My advise will be to use isolated barriers. You can look into for all details and technical articles in MTL website.

Cheers,
Ashok Hait
 
I think your question should have been the difference between Isolated barrier and zener barrier.

Zener barriers are used in Intrinsically Safe (IS) loops for hazardous area application. Isolators are normally used in non-hazardous area two provide one or more than one output from a single input. Inputs and outputs are isolated - that's why the name.

Isolated barriers are one kind of isolators which are used in hazardous area and does the same function like a zener barrier. There are many advantages for using Isolated barriers e.g.

1. Zener barriers need separate IS earth. No IS earth is required for Isolated barriers;

2. For zener barriers you need to be careful about the complete loop resistance including barrier resistance. For isolated barriers overall load resistance calculation is very easy and normally can drive higher load resistance than zener barrier;

3. For zener barrier you must be very careful about the ground loop problems. If the input transmitters or output indicator/controller do not have isolated circuits or common ground, you may end up in complex ground loop problems. Isolated barriers are free from such ground loop problems;

4. Isolated barriers are 4-wire device, but again this doesn't make any difference since the device will be installed in the panel and separate power supply is not a problem;

5. Zener barriers are less costly than isolated barriers

My advise will be to use isolated barriers. You can look into for all details and technical articles in MTL website.

Cheers,
Ashok Hait
Respected Sir,
So, Isolator and Isolated Barrier are same thing or different????
 
There are general purpose isolators (4-20mA in; 4-20mA out) that are not rated for intrinsically safe application; they're just used for isolation. If that's what you call an 'isolator' then a general purpose isolator is different from an I/S rated isolated barrier.
 
There are general purpose isolators (4-20mA in; 4-20mA out) that are not rated for intrinsically safe application; they're just used for isolation. If that's what you call an 'isolator' then there a general purpose isolator is different from an I/S rated isolated barrier.
Ok. Thank you Sir for your reply.
 
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