read multiplexed BCD

[nyc_(is_out_of_here)]

Not strictly a LabVIEW question.  But has anyone read multiplexed BCD using LabVIEW?

I'm thinking I'd have to do some kind of digital I/O but if there is a more elegant off-the-shelf solution,

I'd be very interested.

Thanks in advance.

[GerdW]

Hello nyc,

can you explain what a "multiplexed BCD" is?
I know, what BCD's are: BinaryCodedDecimal, each 4 bits hold a number from 0 to 9.
So where is your multiplexing? Do you want to know how to get just the 4 bits for each digit and convert them to an integer?

[nyc_(is_out_of_here)]

The outputs are coming from a digital panel voltmeter the DMS-40PC made by Datel.

The multiplexing comes from that the same 4 pins are used for all 5 digits and there is a strobe signal output etc.

Message Edited by nyc on 05-10-2006 11:32 AM

[GerdW]

Hello nyc,

so you probably get the digits one after the other, separated by the strobe...
Just read the 4 bits, put them into a number, read the next 4 bits (after getting the strobe signal), put them to the next number and so on.
If you do this in a loop you can use auto-indexing to get an array of digits.

[nyc_(is_out_of_here)]

Yes, it would mean another DIO card for the PC.

I was just wondering/hoping if there was another solution that I hadn't thought of before.

Thanks.

[GerdW]

Hello nyc,

now I understand your question: you just want to know how to get the data from the dmm to the pc! 'Just' a hardware question 🙂

The problem with standard IO card can be the strobe signal. From scratch I don't know a card allowing for a strobe for each 4 input bits.
After reading the pdf from datel-europe.com I would maybe use a simple hardware (with some TTL chips) to latch the data from the DMS. There are some chips available to latch 4bits of data (or even 2 or 4 groups of 4bits). Disadvantage of this approach: you need 20 (plus polarity-bit) digital inputs to read the data in. But otherwise even simple digital IO-cards give you atleast 32 bits...

[daveTW]

Hi all,
as I understood nyc's question, he wants to avoid additional hardware. Could it be a solution, to connect the DMM to the parallel port and read the pins with the "connectivity"->"port I/O"- VIs. Has anybody experience with this under Win2K/WinXP?
Dave

[nyc_(is_out_of_here)]

Thanks for all the input.

It does look like there isn't a drop in and play solutiion.

Now the-powers-that-be are talking about re-design of the product so since there isn't a simple workaround, I will have to make do until the redesign is done.