Warner Electric CBC-1000 - Manual (Page 9)

7 Warner Electric • 800-825-9050 P-275 • 819-0496
Operation
The CBC-1000 system cycle to cycle accuracy will
usually be plus or minus several encoder counts.
Various factors can affect positional
accuracy, the most significant of which are
discussed below:
Encoder Selection
a. Type - Only quadrature type encoders may be
used.
b. Location - The encoder should be mounted
as close as possible to the location where
accuracy is desired, minimizing the effects of
backlash and slippage. Direct mounting is
preferred to indirect mounting.
c. Resolution - Encoder resolution should be
maximized so the inherent plus or minus
several count tolerance equates to the
minimum linear or rotational inaccuracy. The
product of encoder counts and rotational
speed must be less than the input speed of
20,000 pulses per second (20kHz). The
adjacent table simplifies selection:
d. System Resolution - Can also be increased
by mechanical means. For example,
decreasing the diameter of a nip roll
connected to the encoder will increase
system resolution.
The maximum encoder resolution at any operation
speed is:
1
x 20,000 x 60 = Max. PPR
RPM
Clutch/Brake Control
Various velocity profiles may be achieved by properly selecting the clutch/brake control. These can
generally be classified as overexcitation, on-off, and soft start/stop as depicted by the profiles below.
These are shown in order of decreasing system accuracy. Accompanying each diagram are the
recommended clutch/brake controls per given classification. The control should have solid-state
switching. This will reduce unnecessary time delays inherent in electromechanical or mechanical
switching devices. In addition, the system will not require external components such as relays, etc.
Speed Speed Speed
On - Off
CBC-400
Time
Soft Start/Stop
Time
CBC-500
Note: Remove the brake autogap for
best accuracy when soft stopping.
Overexcitation
Time
CBC-700
CBC-750
Encoder Speed Encoder Resolution
(RPM) (pulses/rev.)
12,000 - 4,801 100
4,800 - 2,001 250
2,000 - 1,001 600
1,000 - 0 1200
480 - 0 2500
240 - 0 5000