CAN-8123/CAN-8223/CAN-8423 user’s manual (Revision 3.00, May/22/2009) ------
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3.4 EMCY Introduction
EMCY messages are triggered when a device internal error occurs, i.e.
after a CANopen device detects the internal error, an emergency message will
be transmitted to the EMCY consumers per time per error event. But the
EMCY message will not be transmitted again if the same error repeatedly
occurs. When error reasons are gone, an emergency message containing the
emergency error code “00 00” will only respond to the specific error fields. So,
by checking the EMCY message, users can understand what happened in the
CAN-8123/CAN-8223/CAN-8423, and then do something about the error
event.
Please note that only the emergency consumers can receive the EMCY
object, and only the CAN-8123/CAN-8223/CAN-8423 can support functions of
the emergency producer.
The general concept regarding EMCY communications is shown below.
An emergency message containing 8-byte of data is called emergency
object data. The abbreviated diagram is shown below, and all fields in the
emergency object data will be described in section 5.3.
Byte 0
1
2
3 4 5 6 7
Content
Emergency Error Code Error register
Manufacturer specific Error Field