Rockwell Automation 1746-XXXX SLC 500 4-Channel Analog I/O Modules User Manual User Manual
Page 46
Publication 1746-UM005B-EN-P - June 2004
4-8 Module Operation and System Considerations
Use the following equation to determine the decimal value for the
current output:
Use the following equation to determine the decimal value for the
voltage output:
Voltage Range
Decimal
Representation for
Output Word
Number of
Significant
Bits
Resolution per
LSB
-10 to +10V dc
- 1LSB
-32,768 to +32,764
14 bits
1.22070 mV
0 to +10V dc
- 1LSB
0 to +32,764
13 bits
0 to 5V dc
0 to +16,384
12 bits
1 to 5V dc
+3,277 to +16,384
11.67 bits
×
Desired Current Output (mA) = Output Decimal V alue
For example, if an output value of 4 mA is desired, the value to be put in the
corresponding word in the output image can be calculated as follows:
×
4 mA
=
6242
Note: The actual resolution for analog current outputs is 2.56348
µ
A per LSB,
where the LSB position in the output word is indicated as:
32,768
21 mA
32,768
21 mA
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
LSB
X
X
X
= Bit Not Used
×
Desired Voltage Output (V dc) = Output Decimal V alue
For example, if an output value of 1V dc is desired, the value to be put in the
corresponding word in the output image can be calculated as follows:
×
1V dc = 3277
Note: The actual resolution for analog voltage outputs is 1.22070 mV per LSB,
where the LSB position in the output word is indicated as:
32,768
10V dc
32,768
10V dc
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
LSB
X
X
X
= Bit Not Used