Epson RC620 Manual page 59

Baud Rate and Maximum Cable Length
Available baud rates are 9.6 kbps, 19.2 kbps, 93.75 kbps, 187.5 kbps, 500 kbps, 1500 kbps,
3 Mbps, 6 Mbps, and 12 Mbps.
PROFIBUS DP requires approximately 1ms at 12 Mbps for transmission of 512 bits input
data and 512 bits output data distributed over 32 stations. The following figure shows
typical PROFIBUS DP transmission times depending on the number of stations and baud
rate.
The maximum cable length is restricted by the baud rate.
Multi-Master Configuration
PROFIBUS DP allows you to install multiple masters in a single physical network.
All slave devices in the network can be accessed by different masters. Only one master on
the network can be used for device configuration.
The following figure illustrates the communication procedure for a multi-master
configuration.
Slave
When the master receives the logic token, it inquires data from its slaves. After all
communications are completed, the master passes the token to another master. In this way,
the master can only communicate with its slaves while it is holding the token. The slaves
respond to only the inquiry from the master. No slave can output any messages.
RC620 Option Fieldbus I/O Rev.8
18
14
500 kbps
10
1.5 Mbps
6
2
2 10
Baud Rate Maximum Cable Length
12 Mbps
6 Mbps
3 Mbps
1500 kbps
500 kbps
187.5 kbps
93.75 kbps
19.2 kbps
9.6 kbps
Token-passing Procedure
Master 1
Master 2
Slave Slave
12 Mbps
Number of Slaves
20 30
100 m
100 m
100 m
200 m
400 m
1000 m
1200 m
1200 m
1200 m
Master 3
Slave Slave
2. Installation
Master-slave communication
Slave Slave
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