Tally memory requirements – Rockwell Automation 1794-OB16D FLEX I/O Diagnostic Modules User Manual User Manual
Page 56
Publication 1794-UM061A-EN-P - July 2006
54 Configure FLEX I/O Digital Modules on a DeviceNet Network
Tally Memory
Requirements
The 1794-ADN FLEX I/O adapter 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.
For example, 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. Assign one address for the
1794-ADN and all the modules that you connect to it.
Device
Input Size of
Device
(bytes)
Output Size
of Device
(bytes)
FLEX I/O adapter—1794-ADN
2
0
digital output module—1794-OB16D
2
2
digital input module—1794-IB16D
2
0
Total
6
2
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
2
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
I/
O
I/
O
I/
O
A
D
N
4
DeviceNet network