Industry Online Support
Technical Forum
Navigation
Rating 
Thanks 17
10 Entries
| 6/2/2014 1:53 PM | |
Joined: 7/2/2008 Last visit: 9/30/2024 Posts: 928 Rating:
|
HelloSMHZ, So any analog module will read the 4-20mA but not all of them can translate the tiny sine wave imposed over the current signal to digital communication. We use HART analog modules when we have some hundreds or thousands of transmitters in the field so we can use thePDM softwareto parameterize these transmitters and positioner remotely (If possible) from the control room. Besides, that you can have some kind of asset management. like giving every transmitter its TAG name, installation date, last maintenance date,...etc. Consequently it will be easier to perform some proactive maintenance as well. [quote user="MicroMan"]If you you use a HART capable card you can use further options, like multiple instruments in the same 4-20mA loop. Advanced instrument diagnostic options get avaliable with this as well. DearMicroMan, 1st thank you for sharing this document (1st time to know it was there). 2nd let me slightly disagree(clarify) with what you said. To the best of my knowledge, Siemens doesn't make multidrop HART masters. So, a single channel will always be connected to a single HART instrument. Best regards, H-H
|
This contribution was helpful to
|
|
| 6/2/2014 5:01 PM | |
Joined: 10/19/2012 Last visit: 4/17/2022 Posts: 315 Rating:
|
Now i am clear with 4-20mA & HART. Thx |
| 8/8/2014 3:24 PM | |
Joined: 4/22/2010 Last visit: 11/18/2024 Posts: 5697 Rating:
|
Hello, Hart is a communication protocol to send digital information over the 4-20 mA line. Digital and though using 0 and 1, it does not mean you can see it as a digital input or output Read all about it here: How HART WorksRegards, Marcjan |
Last edited by: Marcjan at: 8/8/2014 3:24 PMProblem solved? |
|
This contribution was helpful to
|
|
| 8/8/2014 3:31 PM | |
Joined: 9/27/2006 Last visit: 11/18/2024 Posts: 12294 Rating:
|
Hello Wago; Your question is quite open, and various answers could be provided. HART uses FSK transmissions over a standard 4-20 mA signal to encode data for instrument parameter exchanges. So it is a digital transmission, but dedicated for instrumentation (much as ProfibusPA and Fieldbus Foundation, without the FISCO standards). Have a look at the protocol descriptions available on the HART communications site: and http://en.hartcomm.org/hcp/tech/aboutprotocol/aboutprotocol_what.html This is how the HART foundation introduces the protocol: More specifically, HART is a bi-directional communication protocol that provides data access between intelligent field instruments and host systems. A host can be any software application from technician's hand-held device or laptop to a plant's process control, asset management, safety or other system using any control platform. A DIGITAL UPGRADE FOR EXISTING PLANTS Because most automation networks in operation today are based on traditional 4-20mA analog wiring, HART technology serves a critical role because the digital information is simultaneously communicated with the 4-20mA signal. Without it, there would be no digital communication. A CRITICAL, DIGITAL ROLE Hope this helps, Daniel Chartier |
This contribution was helpful to
|
|
| 8/8/2014 3:47 PM | |
|
Posts: 784 Rating:
|
Hello Experts, HART signals:4:20 mA Signals encoding:0 , 1 HART not suitable for instruments with Digital signals. Best regards......
|
Follow us on