Rockwell Automation 1794-ID2 U.MNL INCREMENTAL ENCODER User Manual

Page 55

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5–3

How Communication Takes Place and I/O Image Table Mapping with the DeviceNet Adapter

Publication 1794ĆUM015B-EN-P - May 2001

System throughput, from incremental encoder to backplane, is a
function of:

the configured minimum frequency sample time

the number of channels actually configured for connection to a
specific sensor (0 or 1)

You can set the minimum frequency time during module
configuration. The selection influences the sample data rate, thus
affecting system throughput.

The number of channels included in each input scan also affects
system throughput.

FLEX I/O incremental encoder module data table mapping is shown
below.

Incremental Encoder Module (1794ĆID2) Image Table Mapping

Module Image

I/O Image

Input Size

Output Size

0 to 7 Words

1 to 8 Words

G0 Z0

B0 A0

S1 S0

C1 C0

R

Z1

G1

A1

B1

PD0

PD1

Store 0 - SavedCounter Value on channel 0

Store 1 - SavedCounter Value on channel 1

Channel 0 - current counter value on channel 0

Channel 1 - current counter value on channel 1

Channel 0 - Counter wordreadback
Channel 1 - Counter wordreadback

Code for identification of software version

Channel 0 Control Word- sets the function of counter 0

Channel 1 Control Word- sets the function of counter 1

Channel 0 Preset - value to loador compare with counter 0

Channel 1 Preset - value to loador compare with counter 1

Not used

Not used

Control Word2 - Sets filter function for both channels

System Throughput

Mapping Data into the

Image Table

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