Allen-Bradley ControlNet PLC-5 User Manual page 46

2-6 Planning to Use Your ControlNet PLC-5 Processor
Operation Description
Perform ladder-initiated unscheduled non-discrete I/O data transfers on
Non-discrete I/O
a ControlNet network by using ControlNet I/O Transfer (CIO) instructions.
Data Transfer
The data type for these transfers (CT) has the following information:
• Command:
CIO Instructions
1771 READ
1771 WRITE
1794 READ
1794 WRITE
1794 FAULT ACTION
1794 IDLE ACTION
1794 CONFIG DATA
1794 SAFE STATE DATA
CIP GENERIC
Generic bi-directional
1747 READ INPUT
1747 WRITE OUTPUT
1747 READ M0 FILE
1747 WRITE M0 FILE
1747 READ M1 FILE
1747 WRITE M1 FILE
1747 SAFE STATE
DATA
1747 WRITE FLAGS
1747 CONFIG DATA
• Data-table address in source processor
• Size of message in words
• Network address of destination node
• Slot of destination module
• Port number—set to 2 for the ControlNet network
• Flags:
.TO forces a transfer to time out
.EW indicates that the transfer is waiting for an open connection
.CO transfer is made continuously in Run mode
.ER indicates that the transfer was terminated due to an error
.DN indicates that the transfer was made without error
.ST indicates that the transfer was started
.EN indicates that the transfer instruction is enabled
• Error code—indicates the error when the.ER bit is set
• Done length—indicates the number of words transferred
1785-UM022B-EN-P - February 2002
Table 2.B ControlNet Unscheduled Data-Transfer Operations
reads data from a 1771 non-discrete
I/O module
writes data to a 1771 non-discrete
I/O module
reads data from a 1794 I/O module
writes data to a 1794 I/O module
changes the action a module takes
when it faults
changes the action a module takes
when it is idle
changes a module's configuration
data
changes a module's safe-state data
sends user-specified CIP service
sends user-specified CIP service
which requires reply data
reads data from SLC I/O module
input file
writes data to SLC I/O module
output file
reads data from SLC I/O module
M0 file
writes data to SLC I/O module M0
file
reads data from SLC I/O module
M1 file
writes data to SLC I/O module M1
file
change SLC I/O module safe state
data
change action SLC I/O module
take when it faults and/or goes to
idle
change SLC module's
configuration data
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Features
• As many as 32 1771 READ and/or 1771 WRITE
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CIOs can be active at a time
• Minor fault bit S:17/14 is set when 32 1771
READ and/or 1771 WRITE CIOs are active at a
time
• As many as a total of 8 1794 Flex I/O and 1747
SLC I/O CIOs can be active at a time
• Minor fault bit S:17/15 is set when 8 1794 Flex
I/O CIOs are active at a time
• Any transfer initiated from a Processor Input
Interrupt (PII) or Selectable Timed Interrupt (STI)
program suspends execution of the program
scan until the transfer is completed
Important: This can extend your program scan
by tens of milliseconds.
• No transfer is initiated when the processor is in
Program mode
• Transfers that have been running with the.CO
bit set automatically restart on the
Program-to-Run transition when the Continue
Last step bit is set and the data table has not
changed
• A transfer has a maximum size of 64 words
• If the SFC startover bit is set in the processor
configuration file, continuous CIOs may time out
if you cycle power in RUN mode. If this happens,
the CIO error bit is set. To reset the error bit, the
CIO instruction rung condition must go from
FALSE to TRUE.
See Chapter 4 and Appendices C and F for more
information.
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