Rockwell Automation AutoMax ControlNet Communication Interface Module - Manual (Page 43)

AutoMax ControlNet Module Page 43
Publication number DSMBCN-UM001B-EN-P February 2003
The format for the IODEF statement (used only in V2.1 and earlier) is as
follows:
nnnn IODEF variable_name [SLOT=slot number, &
REGISTER=register number, BIT=bit number]
where:
• nnnn = configuration task line number
• variable_ name = integer or boolean variable. Double integer
variables can be used but should be avoided because of the
possibility that all 32 bits will not transfer in one operation.
WARNING
IF YOU USE DOUBLE INTEGER VARIABLES IN THIS
INSTANCE, YOU MUST IMPLEMENT A SOFTWARE
HANDSHAKE BETWEEN THE TRANSMITTER AND RECEIVER
TO ENSURE THAT BOTH THE LEAST SIGNIFICANT AND MOST
SIGNIFICANT 16 BITS HAVE BEEN TRANSMITTED BEFORE
THEY ARE READ BY THE RECEIVING APPLICATION
PROGRAM. FAILURE TO OBSERVE THIS PRECAUTION COULD
RESULT IN BODILY INJURY.
• slot number = slot number of the module in the rack. This number
may range from 0 to 15.
• register number = AutoMax register number on the module. Register
numbers correspond to 16-bit words on the module.
• bit number = bit number of the I/O point in the register. Bit numbers
range from 0 to 15. Bit numbers are specified for Boolean variables
only.
Any variables contained in the rack configuration are accessible by any
task on any AutoMax Processor in the rack. When AutoMax variables
are referenced in AutoMax tasks, the data is directly obtained from or
written to the register image on the module. The data storage for an
AutoMax variable mapped to an A-B register will always exist in the
module's shared memory.
The registers in the MBCN's register image may be displayed using the
AutoMax Programming Executive Monitor I/O function.