Rockwell Automation 1746-QV,D17466.18 OPEN-LOOP VELOCITY CONTL - Manual (Page 15)

3–5 Setting Up the Software
Publication 1746-6.18 April 1998
Consider the following when you set up your profiles:
•
Extend and retract define the profile with respect to the LDT head:
extend is always away from the head, retract is always towards it
•
Position data changes direction depending on how you set
configuration bit Ge:0/15 for LDT motion:
0 = position data increases when moving away from LDT head
1 = position data increases when moving towards LDT head
•
Each position setpoint triggers from the absolute position data
(I:e.1) as modified by the preset reference.
•
Position setpoints are in units of 0.01”.
For example, enter 2” as 200.
•
If you enter position setpoints in random order, the module places
them in ascending order (P1 = lowest and P7 = highest) with their
associated voltage value.
•
Speed segments are defined increasing from the LDT head,
regardless of position data direction.
•
Speeds are reported in the input image table words 2-7 (I:e.2-I:e.7)
for the previous profile (extend speeds reported during the next
retract profile and vice versa)
•
Voltage values (for speed) are in the range of
"10,000mV in
multiples of 5mV. For example, enter –5.005V as –5005.
Important: Enter voltage values in multiples of 5mV or the module
will fault, causing you to correct and re-download the profile.
•
Voltage values are cleared when you re-program position
setpoints. The profile is cleared when the module loses power or
when you change the value of any G-file configuration word.
Important: Your application may require different position setpoints
and voltage values. Your profiles must be consistent with the physical
parameters of the LDT and G file to guard against damaging hardware.
In general:
•
For relatively faster and smoother motion, use two speed segments
for acceleration and five speed segments for deceleration.
•
Adjust the ramp rate on the proportional amplifier for the smoothest
operation. Initially, start with the ramp disabled (fastest ramp rate).
•
You may compensate for deadband or valve overlap by specifying a
voltage value greater than or equal to the valve’s bias current.
Profile operation depends on how the module reports position data.
With the data-direction bit (Ge:0/15), you select whether:
– position data increasing towards the LDT head (Ge:0/15 = 1)
– position data increasing away from the LDT head (Ge:0/15 = 0)
General Conventions
for Profiles
Profile Operation