NORD Drivesystems BU0550 - Manual (Page 46)

PLC logic for NORD SK 54xE frequency inverters
46 BU 0550 GB-0813
3.5.1.5 RS Flip Flop
Bi-stable function: the output Q1 is set via S and deleted via R1. R1 is dominant if TRUE is set on R1 and S
simultaneously.
Table 63 RS Flip Flop
3.5.1.6 R_TRIG and F_TRIG
Both functions are used for flank detection. If a flank is detected on CLK, Q is set to TRUE until the next
time the function is called up, after which it is reset to FALSE. Q only returns to TRUE for a cycle if a new
flank is detected.

R_TRIG = rising flank

F_TRIG = falling flank
CLK
Q
R_TRIG
Funktions-
aufrufe
Q
F_TRIG
Table 64 R_TRIG and F_TRIG
NOTE
The output of the function only changes if the function is called up. Because of this it is
advisable to continually call up flank detection with the SPS cycle.
VAR_INPUT VAR_OUTPUT
Input Explanation Type Output Explanation Type
S Set BOOL Q1 Output BOOL
R1 Reset BOOL
VAR_INPUT VAR_OUTPUT
Input Explanation Type Output Explanation Type
CLK Set BOOL Q Output BOOL
Function
call-ups