Test and Measurement Forum

adc counts

Post general discussions on using our drivers to write your own software here

adc counts

Postby Flow » Thu Feb 21, 2013 8:14 am

I've got two questions concerning the adc-count of the channels:

1) In the PicoScope 3000 programmer's guide it is said, that the input channels are scaled to 16 bits (page6). In the table there is an example: The maximum value would be in decimal 32512.
But how does this fit to 16 bit? (2^16) / 2 = 32768. Why are there more than 250 unused values?

2) I want to use the Extern-Input for triggering. I guess, that this channel is also scaled to 16 bits!? But to what range are this 16 bits scaled? As far as I understood, it isn't possible to change the range of the Extern-Input, so I assume it is constant...
Flow
Newbie
 
Posts: 0
Joined: Wed Nov 28, 2012 9:05 am

Re: adc counts

Postby Martyn » Thu Feb 21, 2013 2:25 pm

The scope is an 8 bit scope and the values are returned in the top part of the 16 bits, the bottom 8 bits being 0. Hence -32512 (0x8100) to 32512 (0x7F00) 256 unused values. Input trigger levels will work in the same way.
Martyn
Technical Specialist
Martyn
Site Admin
Site Admin
 
Posts: 2344
Joined: Fri Jun 10, 2011 8:15 am
Location: St. Neots

Re: adc counts

Postby BSI » Sun Mar 17, 2013 6:51 pm

Is there a function call equivalent to ps3000aMaximumValue for 4227 and 4224 ? There does not seem to be a corresponding call to the Max ADC with ps4000.dll
Thx
L.
BSI
Newbie
 
Posts: 0
Joined: Wed May 12, 2010 3:15 pm
Location: Canada

Re: adc counts

Postby Martyn » Mon Mar 18, 2013 10:00 am

No there is no corresponding call.

The example code uses defined values as specified in the programmer's guide

Code: Select all
12 bit 4000 series scopes (4224 and 4227)
PS4000_MAX_VALUE 32764    7FFC
PS4000_MIN_VALUE –32764  8004

16bit 4262 scope
PS4262_MAX_VALUE 32767    7FFF
PS4262_MIN_VALUE –32767   8001

Overrun value for streaming mode
PS4000_LOST_DATA -32768  8000
Martyn
Technical Specialist
Martyn
Site Admin
Site Admin
 
Posts: 2344
Joined: Fri Jun 10, 2011 8:15 am
Location: St. Neots


Return to General Software Discussions

Who is online

Users browsing this forum: No registered users and 1 guest