Rockwell Automation 1771-QDC, D17716.5.87(Passport) CLAMP AND EJECT MODE - Manual (Page 160)

Span Your Clamp and Ejector Valves
Chapter 9
9-24
If current settings do not match our recommended values from previous
chapters, we suggest you correct these values now using the download
procedure discussed in chapter 4.
Span Your Clamp Open Velocity Valve(s)
1. Obtain a copy of the flow rate curves provided by your flow valve
manufacturer. The flow rate curves graphically illustrate the flow
through a valve at different voltage or input current levels and at
different pressure drops across the valve’s spool.
2. From the above curves, determine the minimum and maximum clamp
open flows available from your flow valve at the pressure you would
normally run during clamp open operation. Record these flows,
along with the input voltages/current associated with them.
Important: During machine operation, If your application typically sets
the pressure during Clamp Open Slow different from the pressure set
during Clamp Open Fast operations, record values for both pressures.
Complete the following exercises for both sets of data points. (Open Slow
values are recorded in all words with the OSC prefix, and Clamp Open
Fast values are recorded in words with FOC, SOC and TOC prefixes).
3. Convert the min and max flows obtained from your flow curve to
clamp cylinder velocities. This is done by:
Clamp Cylinder Velocity (in/sec) =
Flow (in 3 /sec)
Area (in 2 )
- where area is the inside diameter of the cylinder. This area may
be different for the rod and piston ends of the cylinder:
Area for Rod End =
I.D. of cylinder
2
Rod diameter
2
π −
2 2
Area (no Rod) =
I.D. of cylinder
2
π
2
π
- The flow assumes no restrictions on the exhaust port of the
cylinder.
4. Enter the minimum velocities (usually 0) from the above calculation
into FOC45, SOC45, TOC45, and OSC45. Enter the maximum
velocities into FOC46, SOC46, TOC46, and OSC46.
5. Divide the voltage/current corresponding to minimum velocities by
the full range of the clamp open valve(s) input level to determine the
percent signal outputs for minimum. Enter these values into FOC47,
SOC47, TOC47, and OSC47.