Channel allocation for analog inputs in serial output

[schoday]

Hi,


I was wondering why 32 channels (from channel#20 to 51) have been allocated to 16 analog inputs in the Serial data output format.

I was expecting that all 16 analog inputs could be sent in 16 channels itself because:

Each analog input is encoded into 12-bits of data which can be sent in a single channel bcoz each channel is shown to carry 2 data bytes(16-bits).

Furthermore, the equation given to calculate the voltage uses data from one channel only !!! so what are the extra 16 channels for
(I am refering to the PDF doc from RT that describes the serial data format)

If anyone has a better idea of the serial output format....please let me know.


Regards,
Harsha

[Turby]

Unless we can view the same document you received from RT support its not going to be very easy to help you...

only guessing, but, it could be the document describes the algorithm to decode a single channel, maybe you have to do a bit of work yourself to decode the remaining analogue channels ?

Do you have a VB compiler ? Do you know how to program ?
without this its going to be hard to do what you want.

[schoday]

Hi turby


If you can gimme your mail id....I can email you that doc I received from RT support.

[Turby]

here we go...

t dot harris at robbinsons dot co dot uk dot no spam

replace the "dots" and "at" and delete the no spam part

Hope I can help.

[Patrick911]

Hey guys,
is it the "serial dataformat customer version" pdf file you are talking about?

Greets
Patrick

[Turby]

mmmm how about the "serial data format internal version" ?

It would be nice to know the format of the commands going into the DL1/DL2 to control logging etc - as must happen when Dash 1/2 are connected

If someone has access to the hardware and a serial line monitor that would be great

[Patrick911]

Hey Turby,

that's right, I'm also wondering if there is a special "007" version of the serial data format documentation. Yeah, it would ge greater to get through the software/hardware yourself... there a some good freeware serial software monitors on the web... but it's still difficult. But if it was easy, it would also be boring

Greets,
Patrick

[schoday]

Hey turby,

I am really sorry that i am replying so late.

anyway...i am sending the PDF doc to your email.

btw....I connected the DL2 to the computers COM port and used a Serial
port monitoring software to read the data bytes sent by DL2. When I read
the data stream...I could find only channels 20 to 35 allocated for analog data.

As I did point out before....DL2 uses only 16 channels from 20 to 35 to
transmit the 16 analog inputs. I am guessing that RT allocated extra 16
channels in the serial format for future expansion.

Regards,
schoday

[Turby]

my email address was wrong! it should read

t dot harris at robinsons dot co dot uk no spam

replace the "dots" and "at" and delete the no spam part

Would you mind resending please ?

[RTUSA]

Yes, the second 16 channels are simply reserved for the future.

As far as the "customer version" goes, it is the same as the super secret internal version except that it has a lot more information / explanation.

[schoday]

Hey guys...

Ok..now its official that DL2 is using only 16 channels for the analog data out of the 32 channels allocated for this purpose.

I am going to use only 4 analog sensors...so i have configured the DL2 to transmit only the first four analog channels in the serial stream.

But the problem is that the analog sensor data is appearing in channels 24, 25, 26 and 28. Instead I was expecting them to appear in channels 20 to 23.

Now how do i know for sure which sensor's data is coming in each of these channels if they don't follow the sequence ??

Moreover....the DL2 monitor is even displaying the data from analog Channel#16 even though it has been disabled ??

Can anyone help me figure this out quickly

[Turby]

how about connecting only one sensor at a time and seeing what channel the data is coming out on... at least it should be consistent.

Another thing, if you have set the sample rate to 100 Hz, do you actually see a data sample every time tick ? If not (and why not ?), what is your actual sample rate for each of the four channels (this might make a difference) ...

[schoday]

hey turby...

thanks for that pointer...i'll try connecting only one sensor at a time and
see in which serial channel its appearing.