Parker LVD1 - Page 68

Parker Hannifin S.p.A. - Divisione S.B.C. LVD User’s Manual
68
Example 6: filter (600 msec) for parameter value reading
Example 7: available zero speed window
The object of this function is to cancel the main reference signal when the relative value
falls below a programmable threshold level. In practical terms, a speed window is defined
close to zero, within which the speed is set to zero. The threshold value is set in rpm in
parameter Pr88; parameter Pr89 is used as an additional memory slot.
The following program must be entered in the pico-PLC:
SUB
ADD
DIV
99.13
81.15
60 60 60
35 60 60
60 76 81
ADD
92 76 92
MUL
81 71 81
99.0
LD
99.13
ADD 35,60,60
LD 99.0
DIV 60,76,81
SUB 60,60,60
ADD 92,76,92
LD 81.15
MUL 81,71,81
Add Pr35 and Pr60
if timer 1 expired calculate filtered Pr35
setting
result in Pr81
zero set Pr60
reset timer 1 to 600 milliseconds
if Pr81 is negative its sign is changed
LD
99.13
ADD 07.72.89
LD 89.15
MUL 89.71.89
LD 99.13
SUB 89.88.72
AND 99.2
OUT
40.6
Copy the analog reference value in
Pr89
if Pr89 < 0 then invert Pr89 to obtain
the modulus
calculate the difference between Pr89
and Pr88:
if the result is negative, stop the drive
ADD
99.13
99.13
40.6
07 72 89
89.15
99.2
MUL
89 71 89
SUB
89 88 72