Rockwell Automation 20-750-DNET PowerFlex DeviceNet Option Module - Manual (Page 47)

Rockwell Automation Publication 750COM-UM002B-EN-P - October 2012 47
Configuring the I/O Chapter 4
either view option module Diagnostic Items 7 (Input Size) and 8
(Output Size) or calculate them.
View Diagnostic Items 7 and 8 for Input/Output Byte Sizes
Use the 20-HIM-A6 or 20-HIM-C6S HIM, or another drive
configuration tool such as Connected Components Workbench,
DriveExplorer, or DriveExecutive software to view Diagnostic Items 7
and 8. The option module automatically calculates the number of bytes
for the Input Size and Output Size based on the values of
Device
Parameters 2 - [DLs From Net Cfg] and 4 - [DLs To Net Cfg]
configured in Setting a Master-Slave Hierarchy (Optional) on page 27 .
Calculate the Input/Output Byte Sizes
You can easily calculate the number of bytes for the Input Size and
Output Size. Since the option module always uses the 32-bit Logic
Command, 32-bit Feedback, 32-bit Logic Status, and 32-bit Reference,
at least 8 bytes must be set for both the Input Size and Output Size. (A
32-bit word is four bytes.) If any or all of the drive’s sixteen 32-bit
Datalinks are used (see
Setting a Master-Slave Hierarchy (Optional) on
page 27 ), increase the Input and Output Size settings accordingly.
• Input Size: Multiply the number of Datalinks used to write data
(value of
Device Parameter 02 - [DLs From Net Cfg]) by 4 bytes,
and add this result to the minimum 8 bytes. For example, if
Parameter 02
has a value of ‘3’, add 12 bytes (3 x 4 bytes) to the
required minimum 8 bytes for a total of 20 bytes.
• Output Size: Multiply the number of Datalinks used to read data
(value of
Device Parameter 04 - [DLs To Net Cfg]) by 4 bytes, and
add this result to the minimum 8 bytes. For example, if Parameter
04
has a value of ‘7’, add 28 bytes (7 x 4 bytes) to the required
minimum 8 bytes for a total of 36 bytes.
18. Set the scan rate for the selected data exchange method.
For more information about scan rates, see RSNetWorx for DeviceNet
software online help.
19. Click OK.
If a Scanner Configuration dialog box appears, click Yes to continue. The
Edit I/O Parameters dialog box closes and then the 1756-DNB Scanlist
tab dialog box reappears.
20. Click the Input tab to display the input registers for the 1756-DNB
scanner.
Data Exchange Method Rate Field Pull-down Setting
Polled Poll Rate
Change of State Heartbeat Rate
Cyclic Send Rate