Rockwell Automation 20-COMM-D DeviceNet Adapter Series B FRN 2.xxx - Manual (Page 156)

6-28 Using Explicit Messaging
20-COMM-D DeviceNet Adapter User Manual
Publication 20COMM-UM002G-EN-P
SLC 500 Controller Explicit Messaging Using the Read/Write Parameter
Service
SLC 500 Controller Example Ladder Logic Program to Read a Single Parameter
A Read Parameter message is used to read a single parameter. This read
message example reads the value of parameter 003 - [Output Current] in a
PowerFlex 7-Class drive.
Important: Parameter Object Class code 0x0F is not supported in
PowerFlex 750-Series drives. To do a single parameter read,
follow the Generic Get/Set Attribute Service single read
example on
page 6-32 .
Figure 6.29 Example Ladder Logic to Read a Single Parameter
SLC 500 Controller – Formatting a Message to Read a Single Parameter Using
Read/Write Parameter Service
Figure 6.30 Read Parameter Message Configuration Screen
The following table identifies the data that is required in each box to
configure a message to read a single parameter.
General Tab Example Value Description
1747-SDN Slot
Size of Send Data (Bytes)
Message Timeout
DeviceNet Addr
Service (1)
Instance
1
0
5
1 (Dec.)
Read Parameter
3 (Dec.)
The chassis slot occupied by the scanner.
Number of bytes to be sent. For a read message, always set to zero (0).
The time (in seconds) that the message must be completed.
The node address of the adapter connected to the drive.
Code for the requested service.
Instance number is the same as the parameter number.
(1) The default setting for Service is ‘Custom’, enabling entry of a Service Code not available from the Service pull-down menu. When choosing
a Service other than ‘Custom’ from the pull-down menu, an appropriate Hex. value is automatically assigned to the Service Code box which
is dimmed (unavailable).