ifm electronic RM3001 - Handbuch (Seite 55)

55
Note!
The length of the diagnostic information of class 1 is limited to 16 bytes. It is compatible with former DP
versions.
For Profibus-DP encoders of class 2 the length of the encoder-specific diagnostic data including the
extended diagnostic header is 51 bytes (33 hex).
The DDLM_Slave_Diag memory range up to octet 99 is reserved for future diagnostic data of class 2.
3.4.1 Diagnostic header
The header byte specifies the length of the encoder diagnostics including the header byte. The format of
the transmission length is hexadecimal. For the Profibus-DP encoder of class 1 the length of the encoder-
specific diagnostic data is 10 bytes (0A hex).
DDLM_Slave_Diag
Octet 7
Bit 7 6 5 - 0
Data 0 0 xxh
set to 00. length including
header
extended diagnostics
3.4.2 Alarms
An alarm is given if a malfunction in the encoder can lead to incorrect position values. Octet 8 in the
diagnostic function (DDLM_Slave_Diag) indicates the status of the alarms. Additional alarms for device
class 2 are added in the diagnostic octet 17.
If an alarm is given, the Ext_Diag bit and the Stat_Diag bit in the diagnostic function are set to high until
the alarm is reset and the encoder can provide a correct position value. Alarms can be reset (deleted)
when all encoder parameters are within the specified value ranges and the position value is correct.
Note
Not every encoder supports every alarm. For encoders of class 2 the diagnostic information "supported
alarms" (see chapter 0) enables to find out which individual alarm bits are supported.
DDLM_Slave_Diag
Octet 8
Bit 7 - 0
ALARMS