HART Practical Limits 1

[Herman2]

Any words of wisdom on the practical limits of HART protocol in terms of loop length, etc. for digital communication of instrument transmitter data in a factory?

Wire type/size, maximum number of transmitters, noise problems, etc.

Is this the right forum?

Thanks.

 

[don01]

herman2
I've just dug out a Rosemount hart protocol manual dated 1988 and it briefly discusses connection techniques and the use of a Bell202 modem and telephone lines. (i seem to recall a Hayes modem as well) at the blistering speed of 1200 baud. This would indicate you can get some very long Tx distances if you wish.

Now to be accurate HART protocol is one of the agreed data formats for industrial instruments' communication and is intended for multidrop data tx/rx or using the 4-20 mA line. I've seen and used this type of gear in very large chemical plants so 100s of metres is definately achievable.

Some issues are barriers other gear in use. MTL sell barriers specifically designed for smart type instruments.
Note that some smart instruments (actually a lot of them) draw a substantial load as they fire up from power off and this should be considered in your systems

For more specifics I recommend contacting the instrument suppliers of the gear used on your plant.

If you've got a specific question I will try to dig up an answer

Regards
Don

 

[xnuke]

Look at:

http://www.hartcomm.org/

xnuke

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