Allen-Bradley ClutchBrake PLC-5 Series - Internal Timers

1–11Overview of the Clutch/Brake Control System
Publication 65566.5.1 - October 1996
Figure 1.6
Shaft
Rotation for a 21 ms Response Time of the Clutch/Brake
Control System
100
90
80
70
60
50
40
30
20
10
0
03 691215
SPM
Degrees of Shaft Rotation
Important: When estimating the braking distance in degrees of rotation,
you must add the response time of the control system (Figure 1.6) to the
specified downstroke or upstroke braking distance of your press.
If you program additional ladder logic for other press functions in
processor A or B, you will increase the scan time of that processor.
Program scans in both processors are not synchronized, so minimize
the scan time of one processor.
ATTENTION: You are responsible for system response
time. The combination of fast press stroking and additional
program logic could extend the stopping time, resulting in
possible death, personal injury, and/or damage to the press
and/or tangential machinery.
Where fast press stroking and considerable program logic are required
for your application, consider an independent PLC-5 processor for other
press functions.
The clutch/brake control program contains timers with factory-set presets.
You may change timer presets to time out faster, but never slower than the
factory-set presets. See chapter 4. Examples of internal timers include:
Type of Timer Preset (sec)
Antitiedown 3
Motion Detector 3
Arm Continuous 5
Clutch or Auxiliary Valve Feedback 1
Internal Timers