22
MOVITRAC
®
31.. PROFIBUS Fieldbus Interface
3
The PROFIBUS-DP
Interface
3 .1.7
Configuring for 3 PD + Parameter Channel
Control of the MOVITRAC
®
31.. inverter using three process data words and an additional parame-
ter channel requires two identifier bytes to be defined. Identifier byte 1 contains the code for the
parameter channel, identifier byte 2 contains the code for three process data words. Fig. 23 shows
how these two identifier bytes are coded. These codes must be sent to the inverter by the DP
master when PROFIBUS-DP is started so that the DP master and the DP slave can exchange three
process data words as well as the parameter channel.
01174AEN
Fig. 23: Configuration example for parameter c 3 process data words
Fig. 24 shows the communication between the automation unit (DP master) and the MOVITRAC
®
31.. inverter via three process data words and the parameter channel for reading and writing of
drive parameters. This configuration could be used, for example, to control the inverter with
Control Word 1, Speed Setpoint, Process Ramp and Status Word 1, Speed Actual Value, Apparent
Current Actual Value resp. and parameterize it via the parameter channel (see SEW documentation
Fieldbus Unit Profile User Manual).
01175AEN
Fig. 24: Communication with 3 process data words and parameter channel
3 .2
Ident Number
Each DP master and DP slave must have an individual identification number assigned to them by
the PROFIBUS User Group so that the units connected to the bus can be uniquely identified. When
the PROFIBUS-DP master is started, it compares the Ident Numbers of the connected DP units
with those specified by the user. User data transfer is activated once the DP master has ascertained
that the connected station addresses and unit types (Ident Numbers) agree with those specified.
This process provides a high degree of security against configuration errors.
LSB
MSB
= F2
= 242
hex
dec
LSB
MSB
= F3
= 243
hex
dec
Identifier byte Cfg_Data
for three process data words
Data length: 3 words
Input/output
Word structure
Consistency over
the complete length
Identifier byte Cfg_Data
for parameter channel
Data length: 4 words
Input/output
Word structure
Consistency over
the complete length
1
1
1
1
0
0
1
0
1
1
1
1
0
0
1
1
MO
VI
TR
AC
®
841
E
Q
RUN
BUS
FAULT
Fieldbus
CONTROL MODE
Parameter channel
Parameter channel
PD 1
PD 1
PD 2
PD 3
PD 2
PD 3
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