Analog Control Nibble and Example
The
ADC-1R2
Series
I/O modules equipped with analog inputs utilizes the Linear
Technologies LTC1296 analog to digital conversion chip. In the process of performing a
data sample, the user sends a control nibble to the
ADC-1R2
Series
module. The
ADC-1R2
Series
module in turn performs a data conversion using the control nibble and
transmitts a response data sample back. The following table lists each of the 16 possible
analog configurations.
NOTE
•
All numeric data is represent as ASCII Hexadecimal integers
•
The symbol
↵
equates to a carriage return (decimal 13, hex 0x0D)
•
See
Analog I/O Technical Information
section for sample to volts conversion
Control Nibble
Analog Sample
0
Differential: CH0+ CH1-
1
Differential: CH2+ CH3-
2
Differential: CH4+ CH5-
3
Differential: CH6+ CH7-
4
Differential: CH0- CH1+
5
Differential: CH2- CH3+
6
Differential: CH4- CH5+
7
Differential: CH6- CH7+
8
Single Point: CH0
9
Single Point: CH2
A
Single Point: CH4
B
Single Point: CH6
C
Single Point: CH1
D
Single Point: CH3
E
Single Point: CH5
F
Single Point: CH7
Command
Sent by Host
Response
Sent by I/O Module
Description
Q0
↵
Q0
00F
↵
Bipolar sample differential CH0+ CH1-
(Control = 0)
Analog sample = 0x00F (decimal 15)
UA
↵
UA
123
↵
Unipolar sample CH4 (Control = A )
Analog sample = 0x123 (decimal 291)