Program instructions 
  7.6 Counters 
S7-200 SMART 
System Manual, V2.3, 07/2017, A5E03822230-AF 
281 
Change direction in modes 0 and 1 
The following steps describe how to configure HSC0 for change direction for single-phase 
counter with internal direction (modes 0 and 1): 
1.  Load SMB37 to write the desired direction: 
SMB37 = 16#90 
–  Enables the counter 
–  Sets the direction of the HSC to count down 
SMB37 = 16#98 
–  Enables the counter 
–  Sets the direction of the HSC to count up 
2.  Execute the HSC instruction to cause the CPU to program HSC0. 
Loading a new current value (any mode)  
The following steps describe how to change the counter current value of HSC0 (any mode): 
1.  Load SMB37 to write the desired current value: 
SMB37 = 16#C0 
–  Enables the counter 
–  Writes the new current value 
2.  Load SMD38 (double-word-sized value) with the desired current value (load with 0 to 
clear it). 
3.  Execute the HSC instruction to cause the CPU to program HSC0. 
Loading a new preset value (any mode)  
The following steps describe how to change the preset value of HSC0 (any mode): 
1.  Load SMB37 to write the desired preset value: 
SMB37 = 16#A0 
–  Enables the counter 
–  Writes the new preset value 
2.  Load SMD42 (double-word-sized value) with the desired preset value. 
3.  Execute the HSC instruction to cause the CPU to program HSC0.