30
MOVIDRIVE
®
PROFIBUS DFP11A
3
The PROFIBUS-DP
Interface
3.7.3 Writing a Parameter via PROFIBUS-DP (Write)
When executing a WRITE service via the parameter channel, the handshake bit should not be tog-
gled until the entire parameter channel has been set up accordingly for the service in question, as
the parameter channel is transferred on a cyclic basis. Adhere to the following sequence of opera-
tions to write a parameter:
1.
Enter the index of the parameter to be written in byte 2 (Index High) and byte 3 (Index Low).
2.
Enter the data to be written in bytes 4...7.
3.
Enter the Service Identifier for the Write service in the management byte (byte 0).
4.
Transfer the Write service to the drive inverter by toggling the handshake bit.
The drive inverter now processes the Write service and returns the acknowledgement by toggling
the handshake bit.
Fig. 29 shows how the WRITE service is coded in the management byte. The data length for all
SEW drive inverters is 4 bytes. Transfer of this service to the drive inverter is by toggling the hand-
shake bit. A WRITE service to SEW drive inverters therefore generally has the management byte
code 32hex or 72hex.
00151AEN
Fig. 29: Coding of the WRITE service in the management byte
0
0/1
1
1
0
0
1
0
7
6
5
4
3
2
1
0
Byte 0: Management
Service identifier:
010 = Write
Reserved
Data length:
11 = 4 byte
Handshake bit
must be toggled for
each new service
Status bit
0 = correct execution of service
1 = faulty execution of service
0/1 = bit value is toggled