Siemens Simatic S7-200 System Manual page 214

Instruction Set
Connecting the Input Wiring for the High-Speed Counters
Table 10-4 shows the inputs used for the clock, direction control, reset, and start functions
associated with the high-speed counters. These input functions are described in Table 10-5.
Table 10-4
High-Speed Counter
HSC0
HSC1
HSC2
Addressing the High-Speed Counters (HC)
To access the count value for the high-speed counter, you specify the address of the
high-speed counter, using the memory type (HC) and the counter number (such as HC0).
The current value of the high-speed counter is a read-only value and can be addressed only
as a double word (32 bits), as shown in Figure 10-15.
Format:
HC 2
High-speed counter number
Area identifier (high-speed counter)
Figure 10-15
10-26
Dedicated Inputs for High-Speed Counters
I0.0
I0.6, I0.7, I1.0, I1.1
I1.2, I1.3, I1.4, I1.5
HC [high-speed counter number]
MSB
31
Most significant
Byte 3
Accessing the High-Speed Counter Current Values
Inputs Used
HC2
Byte 2 Byte 1
S7-200 Programmable Controller System Manual
C79000-G7076-C230-02
HC1
LSB
0
Least significant
Byte 0