Set Velocity Control Limits - Allen-Bradley 1771-QDC Manual

Plastic molding module
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Chapter 7
Load Initial Configuration Values

Set Velocity Control Limits

7-22
Minimum Velocity Control Limit
(INC45)
The value in this word corresponds to the minimum controllable ram
(screw) velocity during the injection profile. The QDC module uses this
word with Selected Velocity Valve, Output for Minimum (INC47) below.
The QDC module expects this velocity when setting its selected velocity
valve to the percentage output you enter in INC47.
We recorded zero on Worksheet 7-A.
Maximum Velocity Control Limit
(INC46)
The value in this word corresponds to the maximum controllable ram
(screw) velocity during the injection profile. The QDC module uses this
word with Selected Velocity Valve, Output for Maximum (INC48) below.
The QDC module expects this velocity when setting its selected velocity
valve to the percentage output you enter in INC48.
Record the maximum ram (screw) speed per your OEM specifications on
Worksheet 7-A.
Selected Velocity Valve, Output for Minimum
(INC47)
The QDC module uses this word with Minimum Velocity Control Limit
(INC45) above. Enter the %-signal output that the QDC module uses to
drive the selected velocity valve for minimum profile velocity. The QDC
expects a velocity equal to INC45 when setting the selected velocity valve
to this %-output.
The QDC module uses this setpoint to drive the selected velocity valve
when attempting to attain zero ram (screw) velocity. It should drive the
selected velocity valve to a spool position that prohibits any hydraulic flow
into the hydraulic cylinder during injection.
Determine the Output for Minimum value as follows:
0 (0%) for uni-directional direct acting valves
5000 (50%) for bi-directional valves
9999 (100%) for uni-directional reverse acting valves
If your selected
Then the value in
velocity valve is:
INC47 should be
Direct acting
less than value in INC48
Reverse acting
greater than value in INC48
Record the initial Output for Minimum value on Worksheet 7-A.
And during the profile, the QDC module
does NOT drive the valve with a % output
less than value in INC47
greater than value in INC47

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