Allen-Bradley PowerFlex 700AFE User Manual

Rockwell Automation Publication 750COM-UM009A-EN-P - May 2017 107
Using Explicit Messaging Chapter 5
Formatting a Message to Write Multiple Parameters
Figure 27 - Scattered Write Multiple Message Configuration Dialog-boxes
The following table identifies the data that is required in each box to configure
a message to write multiple parameters.
Configuration Tab Example Value Description
Message Type
Service Type
(1)
Service Code
(1)
Class
Instance
Attribute
(2)
Source Element
Source Length
Destination
CIP Generic (network)
Custom
4e (hexadecimal)
93 or 9F (hexadecimal)
(4)
0 (Dec.)
0 (hexadecimal)
Scattered_Write_Request
(5)
40-bytes
(5)
Scattered_Write_Response
(6)
Used to access the DPI Parameter Object in the drive.
Required for scattered write messages.
Code for the requested service.
Class ID for the Class ID for the DPI Parameter Object or Host DPI Parameter Object.
Required for scattered write messages.
Required for scattered write messages.
The tag for the request service data.
Number of bytes of request service data.
The tag for the response service data.
Communication Tab Example Value Description
Path
(3)
My_PowerFlex_755T_Drive The path is the route that the message follows.
Tag Tab Example Value Description
Name Scattered_Write_Message The name for the message.
(1) The default setting for Service Type is ‘Custom’, which enables the entry of a Service Code not available from the Service Type pull-down menu. When choosing a Service
Type other than ‘Custom’ from the pull-down menu, the appropriate hexadecimal value is automatically assigned to the Service Code box, which is dimmed
(unavailable). When writing to 32-bit REAL (floating point) parameters, as in this example, data conversion that is using COP (copy) instructions or UDDTs is required to
write the parameter values.
(2) Scattered writes always write parameter values to the nonvolatile storage (NVS) of the drive, which retains these values even after the drive power is cycled. Important:
Be cautious as the NVS can quickly exceed its lifecycle and cause the drive to malfunction.
(3) Click ‘Browse’ to find the path, or type in the name of the device listed in the I/O Configuration folder (for this example, My_PowerFlex_755T_Drive).
(4) See Table 8 on page 96
for limitations of PowerFlex 755T drives when using DPI Parameter Object Class code 0x93 or host DPI Parameter Object Class code 0x9F for
Explicit Messaging.
(5) In this example, we are writing to five 32-bit REAL (floating point) parameters. Each parameter being written to requires two contiguous DINT registers. Therefore, a
controller tag was created with its Data Type field set to the name of the UDDT of five interleaved DINTs and REALs. Also, the Source Length field on the Message
Configuration dialog box must correspond to the selected Data Type in bytes. For this example, 40-bytes for an array of five scattered REAL structures). Scattered write
messages always assume that every parameter being written to is a 32-bit parameter, regardless of its actual size. Maximum message length is 256-bytes, which can
write up to 32 parameters, regardless of their size. For parameter numbers, see DPI Parameter Object on page 145
(Class code 0x93) or Host DPI Parameter Object on
page 163 (Class code 0x9F).
(6) The controller tag for ‘Scattered_Write_Response’ must be the same size as the controller tag for ‘Scattered_Write_Request’ (for this example, 40-bytes). An array of
DINTs is suggested to be able to read any error codes that are returned.

Allen-Bradley PowerFlex 700AFE Specifications

General

Brand	Allen-Bradley
Model	PowerFlex 700AFE
Category	Controller
Language	English