Rockwell Automation 20-COMM-M Modbus/TCP Adapter - Manual (Page 43)

Using Modbus/TCP Function Codes 4-7
20-COMM-M Modbus/TCP Adapter User Manual
Publication 20COMM-UM014C-EN-P
Speed Feedback uses the same scaling as the speed Reference.
For Reference/Feedback details about other DPI drives, refer to their
respective User Manuals.
Reading the Logic Status and Feedback
On Modbus/TCP, you can read the Logic Status word using any of the
following function codes:
•
Function Code 02 — For example, to verify that a PowerFlex 70/700
drive is ready (bit 0), read register address 1 (
Table 4.G ).
•
Function Code 03 or 23 — For example, to read the complete Logic
Status word in a PowerFlex 70/700 drive, read register address 10001
(
Table 4.H ).
Table 4.G shows that there are 16 discrete registers to represent the Logic
Status word bit by bit. These registers are used only for reading single bits
or multiple bits of status.
TIP: For PowerFlex 700 VC drives (firmware v3.xxx or higher), Parameter
299 - [DPI Fdbk Select] enables you to select the feedback data coming
from the drive over DPI. The default is “Speed Fdbk” in Hz or RPM
determined by Parameter 079 - [Speed Units]. The data selection for
Parameter 299 is also displayed on the 1st line of the HIM and on
DriveExplorer and DriveExecutive screens in the drive status area of the
screen.
Table 4.G Logic Status Registers (to Controller from Drive)
Register
Address Logic Status Bit PowerFlex 70/700 Example
Description Values
1 0 Ready 0 = Not Ready (Par. 214)
1 = Ready
2 1 Active 0 = Not Active (Running)
1 = Active
3 2 Command Direction 0 = Reverse
1 = Forward
4 3 Actual Direction 0 = Reverse
1 = Forward
5 4 Accel 0 = Not Accelerating
1 = Accelerating
6 5 Decel 0 = Not Decelerating
1 = Decelerating
7 6 Alarm 0 = No Alarm (Par. 211 & 212)
1 = Alarm
8 7 Fault 0 = No Fault (Par. 243)
1 = Fault
9 8 At Speed 0 = Not At Reference
1 = At Reference