Bimba PCS Rod Lock - Manual (Page 8)

Employing a Rod Lock with a PCS System
in a Linear Motion Control System
In the event of an air leak, if the Rod Lock is released and the rod is commanded to a new
position, the rod could jolt and the system could become unstable. To prevent this:
• Switch the two 4-way valves so that the PCS system is connected to the cylinder.
• Command a motion in the direction opposite to that of intended travel with the Rod
Lock still engaged to ensure that one side of the piston is energized.
• Delay a small amount of time to allow proper pressurization of the cylinder
• Issue the command to new position, with the Rod Clamp still engaged (this command
will insure the opposite side of the piston is energized).
• Delay briefly to allow pressurization of the opposite side of the cylinder.
• Disengage the Rod Clamp.
Programmed Sequence of Events
1. Command the PCS to move to its position.
2. Wait until either the @Position or Output signal indicates that the payload has
entered the deadband.
3. Delay for a moment to ensure that the system is stable (this is demonstrated when
the payload remains within the deadband zone during the delay).
the payload remains within the deadband zone during the delay).
4. Engage the Rod Clamp.
5. Switch the two 5-port valves so that both of the cylinders ports are at line pressure.
6. Perform whatever operations are required at this position.
7. Switch the two 5-port valves so that both the cylinder’s ports are connected to the
PCS.
8. Command the PCS to move in the opposite direction (with the Rod Clamp still
engaged).
9 D l f h t i d f ti 9. Delay for a short period of time.
10. Command the PCS to move to its next position (with the Rod Clamp still engaged).
11. Delay for a short period of time.
12. Disengage the Rod Clamp.
The durations of time delays (Steps 3, 9, & 11) are determined during system set up. Time
delays are typically 50 to 100 milliseconds. Steps 8 and 9 may not be necessary. The
durations of time delays and the need for steps 8 and 9 depend upon the final system
configuration and variables such as payload, payload orientation, supply pressure, valve
response time, and valve capacity.