ifm electronic RM3001 - Handbuch (Seite 42)

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3 Device configuration
The Profibus-DP devices can be configured and parameters be set according to the user's needs. In this
context it is useful to know that with Profibus there are three types of data transmission.
Configuration
When the system is started, the Profibus devices are configured (DDLM_Set_Prm mode), i.e. the encoder
class set by means of the GSE file in the configuration tool (see chapter 0 Encoder class) and the set
operating parameters (see chapter 0 Operating parameters) are transferred to the respective slave. This
has the advantage that the configuration data need not be modified when a Profibus device is exchanged.
Data exchange
In the normal mode (DDLM_Data-Exchange mode) data are exchanged between master and slaves. The
preset value function can only be carried out in this operating mode. The data exchange is described in
chapter 0.
Diagnostic messages
In the diagnostic mode (DDLM_Slave_Diag) diagnostic data of the slave are transferred on the master's
request. The diagnostic messages are described in chapter 0.
3.1 Encoder class
In general the encoders with Profibus-DP interface are divided into three classes:
CLASS 1
In the configuration class 1 only output words are transferred, depending on the resolution of the encoders
16 bits or 32 bits.
The following functions can be carried out:
- changed direction of counting
- diagnostic data up to octet 16
Configuration data:
- Singleturn
CLASS 1 – 16 bits: D0hex 1 input data word, data consistency
- Multiturn CLASS 1 – 32 bits: D1hex 2 input data words, data consistency
CLASS 2
In the configuration class 2 output and input words are transferred, depending on the resolution of the
encoders 16 bits or 32 bits.
The following functions can be carried out in addition to the class 1 functions.
- scaling function
- preset value function
- extended diagnostic data
Configuration data:
- Singleturn
CLASS 2 – 16 bits: F0hex 1 input data word, 1 output data word for preset value,
data consistency
- Multiturn CLASS 2 – 32 Bit: F1hex 2 input data words, 2 output data words for
preset value, data consistency