Rockwell Automation 20D PowerFlex 700S AC Drives with Phase II Control Reference Manual User Manual

Page 129

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Rockwell Automation Publication PFLEX-RM003E-EN-E - January 2011

129

Detailed Drive Operation Chapter 1

Parameters 232 [Encoder0 PPR] and 242 [Encoder1 PPR] set the pulse per
revolution rating of the encoders. These parameters have a range from 10 to
20000 PPR. Parameter 156 [Start Inhibits], bit 10 “Encoder PPR” will be set if
the PPR value doesn't correspond with any of the bold values in this table:

Parameter 233 [Encdr 0/1 Config] sets the configuration options for the
encoders. The function of the bits in [Encdr 0/1 Config] are as follows:

• Bits 0…3 “Enc0 Filt bx”, or bits 16…19 “Enc1 Filt bx”, configure the

encoder input filter (see

Table 15 on page 130

). The filter requires the

input signal to be stable for the specified time period. Input transitions
within the filter time setting will be ignored. Bits 0…3 (or 16…19) add 100
ns filtering per stage to the encoder inputs.

• Bits 4 “Enc0 4x” and 5 “Enc0 A Phs” or 20 “Enc1 4x” and 21 “Enc1 A Phs”

determine how the encoder channel A and B signals will be interpreted.
Typically, both encoder phases A and B are used so that direction
information is available. Parameter 230 [Encdr0 Position] counts up for
forward rotation and down for reverse rotation. If bit 5 (or 21) is set, then
the B phase signal is ignored. As a result, the encoder position will only
increase, regardless of rotation direction. Bits 4 and 5 (or 20 and 21)
together also determine the number of edges counted per encoder pulse
(see

Table 16 on page 130

). “4x” sampling counts both rise and fall of both

A and B encoder phases, hence 4 edges per pulse. In 4x mode, the encoder
position will change by four times the encoder pulses per revolution (PPR)
rating per encoder revolution (for example, 4x mode increments the value
in [Encdr0 Position] by 4096 for one revolution of a 1024 PPR encoder).

• Bit 6 “Enc0 Dir” or 22 “Enc1 Dir” inverts the channel A input, thus

reversing the direction of the feedback. Note that changes in encoder
direction (bit 6 or 22) may require changing parameter 153 [Control
Options], bit 10 “Motor Dir”.

n =

2

n

=

x

mod 75

mod 125

mod 225

mod 375

mod 625

mod1125

0

1

75

125

225

375

625

1125

1

2

150

250

450

750

1250

2250

2

4

300

500

900

1500

2500

4500

3

8

600

1000

1800

3000

5000

9000

4

16

1200

2000

3600

6000

10000

18000

5

32

2400

4000

7200

12000

20000

--

6

64

--

--

--

--

--

--

7

128

--

--

--

--

--

--

8

256

--

--

--

--

--

--

9

512

--

--

--

--

--

--

10

1024

--

--

--

--

--

--

11

2048

--

--

--

--

--

--

12

4096

--

--

--

--

--

--

13

8192

--

--

--

--

--

--

14

16384

--

--

--

--

--

--

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