Allen-Bradley ClutchBrake PLC-5 Series - Set up or Simulate Rotary Cam Limit Switches; Chapter Objectives; Setting up Position Monitoring Devices

Chapter 7
Publication 65566.5.1 - October 1996
Set Up or Simulate Rotary
Cam Limit Switches
In this chapter, we help you:
• set up your position monitoring (RCLS) devices.
• read status bits in ladder logic to indicate shaft position
• use transition fault bits to stop the press
• simulate RCLSs with ladder logic
• troubleshoot the setup of your RCLSs
The control system can monitor the rotational position of the press
stroke with either of these position-monitoring devices:
• dual assemblies containing rotary cam limit switches
• dual resolvers that require ladder logic to simulate cam limit switches
Important: With either method, you must use dual independent
positional inputs with the same settings so that:
• brake-monitor contacts must close at a point that indicates unsafe
brake wear, and open in the near-bottom zone after the take-over
contacts close
• take-over contacts must close after the press has closed in the near-
bottom zone and open at a point that allows the press to stop at the top
• anti-repeat contacts open during mid-upstroke for at least 75ms.
Position-monitor inputs should operate as follows (Table 7.A):
Table 7.A
Operation
of Cam Limit Switches
This Cam In this Mode W ith these Conditions Provides a Signal That:
AntiRepeat
(ACAM)
Onthehop
in Single stroke
Cams open momentarily after run
buttons are released past bottom
Prevents a second stroke unless run buttons
are pressed a second time
Takeover
(TCAM)
Inch or
Single stroke
Cams open in neartop zone T urns OFF triac outputs for stopping the press
at top of stroke (stopontop)
Continuous Cams open in neartop zone
after stopontop command
Single stroke or
Continuous
Cams close near bottom just when
(or before) BCAM opens
Lets the press complete a single stroke or run
continuously after run buttons are released
Brakemonitor
(BCAM)
Single Stroke or
Continuous
When press stops in downstroke
beyond BCAM closure
Indicates that braking distance is excessive.
T urns OFF solenoid outputs to prevent restart.
Chapter Objectives
Setting Up Position
Monitoring Devices