Epson RC90 - Page 99

2. Installation
RC700 / RC90 Option Fieldbus I/O Rev.14 87
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.
Bus Cycle Time [ms]
500 kbps
1.5 Mbps
12 Mbps
Number of Slaves
2 10 20 30
18
14
10
6
2
The maximum cable length is restricted by the baud rate.
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
100 m
100 m
100 m
200 m
400 m
1000 m
1200 m
1200 m
1200 m
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.
Master 1
Master 3
Slave Slave Slave Slave Slave
Master 2
Slave Slave
Token-passing Procedure
Master-slave communication