FPΣ User's Manual 
 
7.5 PWM Output Function 
151 
7.5  PWM Output Function 
Use the instruction F173_PulseOutput_PWM. This instruction delivers a pulse width 
modulated output signal according to the specified DUT. 
The PWM output status is stored in special internal relays. To access special data registers 
and special internal relays, use the PLC-independent system variables. You can insert system 
variables directly into the POU body: Use the "Variables" dialog without entering a declaration 
in the POU header. Please refer to the FPWIN Pro online help for detailed information on 
using system variables. 
Setting system registers 
When using the PWM output function, make sure the high-speed counter function is not 
allocated to channel 0 or channel 2. 
 
1.
2.
3.
Procedure
 
1.  Double-click "PLC" in the navigator 
2.  Double-click "System Registers" 
3.  Double-click "High-Speed Counter, Pulse-Catch Input, Interrupt Input" 
4.  Set the high-speed counters allocated to channel 0 and channel 2 to 
"Unused" 
 
 
REFERENCE
 
Please refer to the FPWIN Pro online help for details and a programming 
example. 
 
Output relays and system variables for FPΣ 
Channel and pulse output numbers 
Channel no.  Pulse output 
0 Y0 
2 Y3 
System variables for memory areas used 
Description  System variable  Address 
0 sys_bIsPulseChannel0Active R903A 
Pulse output: control flag 
for channel 
2 sys_bIsPulseChannel2Active R903C