User manual

Publication DNET-UM004A-EN-P - March 2004
14-2 Using FLEX™ I/O Modules on a DeviceNet Network
Tally Memory
Requirements
The Flex I/O adapter 1794-ADN packs the data of its I/O modules into
a contiguous block of input or output bytes. By default, the modules
share DINT elements in the scanner.
To determine the amount of scanner memory required for your
adapter and its I/O modules
As an option, give each module its own memory location (DINTs)
within the scanner. This may make your programming easier. See Give
a Value Its Own Memory Location page A-1.
Device Input Size of
Device
(bytes)
Output Size
of Device
(bytes)
Flex I/O adapter—1794-ADN 2 0
digital output module—1794-OB16 2 2
digital input module—1794-IB16 2 2
Total 6 4
Device Address Input Size of
Device
(bytes)
Input Memory
in Scanner
(DINTs)
Output Size
of Device
(bytes)
Output Memory
in Scanner
(DINTs)
start/stop buttons 1 1 1 1
motor starter 4 1 4 1
Flex I/O adapter w/ modules 6 2 4 1
Total
1. Add the input bytes of each module + 2 bytes for the adapter.
2. Add the output bytes of each module (0 for
the adapter).
3. Add the totals to the main tally.
sub-tally
main tally