Rockwell Automation 1746-QV,D17466.18 OPEN-LOOP VELOCITY CONTL - Manual (Page 23)

5–3 Operating the Module
Publication 1746-6.18 April 1998
2. After reversing the sign of voltages (if needed), run the extend
profile again by changing the value in N7:50 to 1.
Observe that the direction of ram travel is correct.
Important: Reset the value in N7:50 to 0.
3. Check the position value reported in the status word, N7:61, as
you run the ram to the end of its travel. If the position data is
reversed, you may need to change the data-direction bit (Ge:5/15)
in the G file off-line as follows:
•
0 = position increases while moving away from LDT head
•
1 = position increases while moving toward LDT head
Important: You must reload profiles for either of these conditions:
•
Changing a value in the G file. (This clears the profiles).
•
When position data exceeds the position setpoint that is
farthest from the LDT head, the profile is disabled and
you must modify position setpoints and reload the profiles.
4. Verify operation of the retract profile by changing the value in
N7:50 to 2. Important: Reset the value in N7:50 to 0, afterwards.
Jog the Ram to the Reference Position
The reference position may require that you jog the ram beyond a
position defined by the profile in the ladder program (appendix B).
You may jog the ram as follows:
1. Observe the current position data (in I:e.1).
2. Modify profile position setpoint(s) to permit the ram to travel to the
required reference position using the current position. For example:
If position data reads –100, change P1 to –1300 (length of the LDT)
3. Important: Reset the value in N7:50 to 0.
Load the profiles into the module.
4. Run the extend profile by changing the value in N7:50 to 1, and
jog the ram to the reference position.
5. At the reference position, the position data, I:e.1, (N7:61) will be an
arbitrary value. Set the position data to the value of the preset
reference by changing the value in N7:50 to 8 (N7:40 must = 0).
Position data will change to preset reference (0 in this example).
6. Verify that N7:61 now reads zero at the reference position.
Important: Once you establish the reference position:
•
the module will maintain the preset reference’s position data in I:e.1
•
all profile position setpoints will be referenced to it
(until you clear Ge:6 by changing any G-file value or set another
reference position. The preset reference is retained during power up.