MOVITRAC
®
31.. PROFIBUS Fieldbus Interface
3 3
The PROFIBUS-DP
Interface
3
00952AEN
Fig. 40: Structure of the management byte
Bit 6 is used as a handshake between controller and inverter. It initiates the execution of the trans-
ferred service in the inverter. As the parameter channel is transferred in each cycle with the proc-
ess data, particularly with PROFIBUS-DP, execution of the service in the inverter must be edge
controlled using the handshake bit 6. The value of this bit is therefore toggled each time a new
service is to be executed. The inverter uses the handshake bit to signal whether the service has
been executed or not. The service is executed as soon as the controller notices that the received
and transmitted handshake bits correspond. Status bit 7 indicates whether the service was exe-
cuted properly or produced an error.
Index Addressing
Byte 2:
Index High and byte 3: Index Low are used to identify the parameter to be read or written
via the fieldbus system. The parameters of an inverter are addressed using a standard index, irre-
spective of the type of fieldbus system. Byte 1 should be considered reserved and must generally
be set to 0x00.
Data Area
As shown in Fig. 41 the data are contained in byte 4 to byte 7 of the parameter channel. This allows
a maximum of 4 byte data to be transmitted per each service. The data are generally entered flush
right, i.e. byte 7 contains the least significant data byte (data LSB), byte 4 correspondingly the
most significant data byte (data MSB).
01189AEN
Fig. 41: Definition of the data area in the parameter channel
7
6
5
4
3
2
1
0
Bit:
MSB
LSB
Service identifier:
000 = No Service
001 = Read
010 = Write
Reserved
Data length:
00 = 1 byte
01 = 2 bytes
10 = 3 bytes
11 = 4 bytes
Handshake bit:
must be toggled for
each new service
Status bit:
0 = correct execution of service
1 = faulty execution of service
Byte 0: Management
Byte 0
Byte 1
Byte 2
Byte 3
Byte 4
Byte 5
Byte 6
Byte 7
High word
High byte 1
High byte 2
Low byte 1
Low byte 2
Low word
Double word
Management reserved
Index high
Index low
Data MSB
Data
Data
Data LSB
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