teds ieee 1451.4

[Alan_Gilchrist]

I'm using Labview 7.1 to program TEDS chips (the DS2430A).

It appears as though SC2350_TEDS_Hardware Write to 1-wire EEPROM.vi writes the complete Data Sheet to the Data Memory.

Doesn't the 2004 version of the IEEE standard require that the Basic TEDS information be written to the Application Register?  This would then place it in the one-time programmable register.

The examples for using a serial port adapter appear to do the same thing.

Am I interpreting the IEEE format incorrectly?

Alan Gilchrist

[Paul_C.]

Hi Alan,

I'm not familiar with the SC2350_TEDS_Hardware Write to 1-wire EEPROM.vi.  Is this the correct name of the VI you are using? Also, depending on when the VI was written it might have followed a different IEEE standard.  From your post, I gather the way the VI writes to the data memory isn't working for your application.  Is this true?

Regards,
Paul C.

[Alan_Gilchrist]

Hello Paul

Sorry, I should have mentioned where the vi came from.  It's part of sc-2350.llb, found here:

http://sine.ni.com/devzone/cda/epd/p/id/4507

I don't believe it was written for the preliminary v0.9 standard, because the manufacturer ID is 14 bits long (in the preliminary standard, it was only 12 bits long).

I am trying to program TEDS chips for my customers, and I want to be sure they follow the IEEE 1451.4 standard.  It doesn't appear that the NI example programs follow the standard, but I'd like to be sure I'm not missing something.

Thanks,

Alan Gilchrist

[Alan_Gilchrist]

Hi Paul

I modified the SC-2350.llb to load the Basic TEDS data into the application register of the EEPROM (see attached).

However, when I do this, the Measurement and Automation Explorer can't read the EEPROM, because it thinks the checksum is wrong.

I assume this is because the checksum is calculated using the data in the application register as well as the data in the data memory, but MAX is only reading the data memory.  Because of this, you cannot read the TEDS nor use it in your application.

For my purposes, I think I can modify the software for the Serial to 1-Wire converter (http://sine.ni.com/devzone/cda/epd/p/id/1500) in a similar fashion.

But this means that the SC-2350 is not IEEE 1451.4 compliant, even though the data sheet and the catalog implies that it is.

Regards,

Alan Gilchrist

Message Edited by ag1 on 08-08-2007 01:50 PM