Data Formats; Current Count And Holding Register Count Value Formats; Table 3-2 24-Bit Count Value Format - Siemens SIMATIC TI505 User Manual

3.2

Data Formats

Current Count and
Holding Register
Count Value
Formats
3-4 Understanding Module Operation
The current count value for each 24-bit counter is contained in two word
inputs (for example, WX1 and WX2).
The count range is from 0 to 16,777,215 in unipolar mode.
The count range is from +8,388,607 to –8,388,608 in bipolar mode.
Overflow and underflow occur at the 0 value.
Table 3-2 shows the word format for the current count and Holding Register
values for the 24-bit counters (Counters 1 and 4).

Table 3-2 24-Bit Count Value Format

Word
MSWord 1 2 3
LSWord 1 2 3
The count values for Counters 1 and 4 are contained in the following words:
Counter 1: Count value: WX1 and WX2
Counter 4: Count value: WX5 and WX6
The Holding Registers for Counters 1 and 4 are the following words:
Counter 1: Holding Register 1: WX9 and WX10
Holding Register 2: WX11 and WX12
Counter 4: Holding Register 3: WX13 and WX14
Holding Register 4: WX15 and WX16
You can select one of the following two's-complement formats to express the
unipolar and bipolar word values:
32-bit signed integer format:
smmmmmmm mmmmmmmm mmmmmmmm mmmmmmmm
Double 16-bit signed integer format:
saaaaaaa aaaaaaaa sbbbbbbb bbbbbbbb
where the numeric value is calculated as:
( (saaaaaaa aaaaaaaa) *32768 + (sbbbbbbb bbbbbbbb) )
MSByte
4 5 6 7 8
4 5 6 7 8
High Speed Counter Encoder Module User Manual
LSByte
9 10 11 12 13 14 15 16
9 10 11 12 13 14 15 16