Diagnostics and Maintenance
9.1
SERCOS® Phase Diagnostics Introduction
At a glance
Aim of this subchapter
What's in this
Section?
This section describes the diagnostics parameter functions for the SERCOS® phase.
This Section contains the following Maps:
Topic
About SERCOS® Phases Standard
GetActualPhase Function
GetCommandedPhase Function
Page
279
280
281
278
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About SERCOS® Phases Standard
Standard IEC
1491
SERCOS® phases
The IEC 1491 Standard (the SERCOS®-based international servo drive communications protocol standard) defines the following five phases of communicating with a SERCOS® drive.
The following table defines the phases:
1
2
Phase
0
3
4
Meaning
The loop is not communicating.
The controller is finding the drives which are on the loop.
The SERCOS® loop timing parameters are exchanged with the drives.
The service channels to the drives are functioning and all timing parameters are being used. The GetIDN and SetIDN functions are ready for operation.
The motion controller is sending cyclic communication information to the drives.
The loop is up and motion commands are allowed.
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GetActualPhase Function
Description This function returns the actual SERCOS® phase of the loop.
How to Use this
Function
This function is implemented with the help of the WRITE_CMD instruction (see
WRITE_CMD, p. 324).
Associated
Language
Objects
Exchange via WRITE_CMD:The table below presents the different language objects linked to this function.
Description Object Name Function code
%MWxy.i.26
ACTION_CMD
%MDxy.i.20
RETURN_CMD_1
550
-
%MWxy.i.19
ERROR_CMD -
Command
Result of the command
Error report. See WRITE_CMD
Command: Programming Errors,
p. 304
.
280
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GetCommandedPhase Function
Description The GetCommandedPhase function returns the SERCOS® loop phase that the movement controller is trying to establish.
Note: Use the GetActualPhase function to determine the current loop phase.
The SetCommandedPhase function requests the movement controller to change the SERCOS® loop to the specified phase.
The SERCOS® phase must always switch phases in an increasing manner. If the
SetCommandedPhase value is lower than the present loop phase, the movement controller will switch the phase to phase 0 and sequence the loop up to the specified phase. If the loop is at phase 4, and a lower phase is commanded, the movement axes will fault.
Note: The movement controller can only progress to the next SERCOS® phase if all the drives on the loop allow a switch to the next phase. Therefore, it is possible that the commanded phase might never be achieved. Use the
GetCommandedPhase function to find out which phase was commanded, and use the GetActualPhase function to discover the actual phase of the SERCOS® loop.
How to Use these
Functions
These functions are implemented with the help of the WRITE_CMD instruction (see
WRITE_CMD, p. 324).
Associated
Language
Objects
Exchange via WRITE_CMD:The table below presents the different language objects linked to these functions.
Description Object
%MWxy.i.26
Name
ACTION_CMD
%MDxy.i.20
%MDxy.i.27
RETURN_CMD_1
PARAM_CMD_1
%MWxy.i.19
ERROR_CMD
-
-
-
Function code
1545
2545
Read command
Write command
Result of the read command
Value to write)
Error report. See WRITE_CMD
Command: Programming Errors,
p. 304 .
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