User guide

RUGGEDCOM ROS
User Guide
Chapter 5
Setup and Configuration
Modbus TCP Performance Determinants 119
The Modbus Server application accepts TCP encapsulated Modbus TCP messages from Client Gateways and
native masters. After removing the TCP headers, the messages are issued to the RTU. Responses are TCP
encapsulated and returned to the originator.
The following illustrates a complex network of Client Gateways, Server Gateways and native TCPModbus
devices.
1
7
4 6
5
8
9
11
10
1
2
3
7
Figure 79: Modbus Client and Server
1. Master (Polling RTUs 1 and 2) 2. Master (Polling RTUs 1, 2 and 4) 3. Native Modbus TCP Master (Polling All RTUs) 4. RMC30
Client Gateway 5. RUGGEDCOM Media Converter Client Gateway 6. Ethernet 7. RUGGEDCOM Media Converter Server Gateway
8. RMC30 Server Gateway 9. RTU 1 10. RTU 2 11. RTU 3 12. RTU 4
Section 5.4.2.2
Modbus TCP Performance Determinants
The following illustrates the possible sources of delay and error in an end-to-end Modbus TCP exchange.