5
PROFIBUS-DP Operating Characteristics
Parameter setting via PROFIBUS-DP
Manual – MOVI-PLC
®
basic DHP11B.. controller
53
The MOVI-PLC
®
basic
DHP11B.. controller now processes the
read
service and sends
the service confirmation back when the handshake bit changes.
The above table shows how a
read
service is coded in management byte 0. The data
length is not relevant, you only need to enter the service identifier for the
read
service.
This service is now activated in the MOVI-PLC
®
basic
DHP11B.. controller when the
handshake bit changes. For example, it would be possible to activate the
read
service
with the management byte coding 01hex or 41hex.
Writing a
parameter via
PROFIBUS-DP
(Write)
Due to the cyclical transfer of the parameter channel, to execute a
write
service via the
8 byte MOVILINK
®
parameter channel, the handshake bit may only be changed if the
complete parameter channel has been set up for the specific service. Observe the
following sequence when writing 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 and the data length for the
write
service in the manage-
ment byte (byte 0).
4. Transfer the
write
service to the MOVI-PLC
®
basic
DHP11B.. controller by changing
the handshake bit.
The MOVI-PLC
®
basic
DHP11B.. controller now processes the
write
service and sends
the service confirmation back by changing the handshake bit.
7 / MSB
6
5
4
3
2
1
0 / LSB
0
0/1
1)
1) Bit value is changed
X
2)
2) Not relevant
X
2)
0
0
0
1
Service identifier
0001 = Read parameter
Data length
Not relevant for read service
Handshake bit
Must be changed on every new task in cyclical transmission.
Status bit
0 = No fault in service execution
1 = Fault during execution of service
0
0
I
