Siemens SIMATIC FM 452, Manual

Page: 96 / 210

Machine Data and Cam Data
8-28
FM 452 Electronic Cam Controller
C79000-G7076-C452-04
Address
(relative)
Name Type Initial Value Comment
For distance cams
+2.0
+6.0 CBEGIN
CEND DINT
DINT L#–100000000
L#100000000 Cam start (CS)
Cam end (CE)
Range:
– 1 000 000 000
m to 1 000 000 000 m
The inactive part of a cam must always have a minimum clearance of four pulses between the cam end
(CE) and cam start (CS).
If CE = CS, the cam is activated for one pulse
.
Minimum Length of a Distance Cam
CE CS
Pulses; calculated from
the encoder signals
Shortest cam
CS = 103 and CE = 103
Shortest non–active
cam, when CS is
greater than CE:
CS = 105 and CE = 101
101 102 103 104 105
CS = CE
s
s
CS = cam start; CE = cam end
106
Figure 8-3 Shortest Cam with the Axis Moving in the Positive Direction
Address
(relative)
Name Type Initial Value Comment
For time cams
+2.0
+6.0
CBEGIN
CEND
DINT
DINT
L#–100000000
L#100000000
Cam start (CS)
Cam end (CE)
On Time
Range:
(0 to 13421) 100 s with a maximum of 16 cams
(0 to 26843) 100 s with a maximum of 32 cams
(0 to 53686) 100 s with a maximum of 64 cams
(0 to 65535) 100 s with a maximum of 128 cams
With a time cam, you specify a cam start and an “on time” instead of a cam end. You can specify the on
time in increments of 100
s. The time starts to run when the cam is activated.
The following conditions apply for specifying the times
•
0 s: A cam with the on time 0 s is never activated.
•
0 s < t 400 s: The FM 452 sets a minimum cam time of approximately 330 s.
•
t > 400 s: The FM 452 calculates the actual on time
t
act
from the specified on time
t
spec
according to
the following formula:
(
t
act
=
Cam cycle time
integer
t
spec
cam cycle
)
The maximum error is always less than one cam cycle period.