PLC to PLC Communications
Unrestricted © Siemens 2020 |
siemens.com/tia |
|
|
Agenda
-PUT/GET S7 Communications
-Modbus/TCP
-Open User communications
-I-Device
-OPC UA
-Flexible F-Link
-Libraries
Unrestricted © Siemens 2020
Page 2
PUT/GET
Advantages
•Single sided – only needs to be programed in one PLC
•Works in all Simatic PLC’s
•Independent of the communication media
•Can be used on all S7 data areas
•Wizard is available for setup in TIA
Disadvantages
•No security
•Blocked by default on the S7-1200 and S7-1500
•Data blocks have to be unoptimised
•Only small amounts of data can be transferred <160bytes
•No acknowledgement of transfer this needs to be
engineered if needed
• Always takes a connection resource
https://support.industry.siemens.com/cs/au/en/view/82212115
Unrestricted © Siemens 2020
Page 3
Modbus/TCP
Advantages
• Cross vendor communication
• Built in diagnostic
• Routable over Ethernet
• Optimized Data blocks are supported
• Defined communications timeout
Disadvantages
• No security or encryption
• No setup wizard
• Server/Client blocks must be programmed
Great for communication to 3rd party devices but can be used for PLC to PLC communications
https://support.industry.siemens.com/cs/au/en/view/102020340
Unrestricted © Siemens 2020
Page 4
Open User Communications
Unrestricted © Siemens 2020
Page 5
TCP, ISO on TCP or UDP
|
TCP |
ISO on TCP |
UDP |
|
|
|
|
Speed |
Rapid |
Rapid |
Very Rapid |
|
|
|
|
Quantity |
Medium to Large |
Medium to Large |
Small to Medium |
|
S7-1500: 64kB |
Same as TCP |
S7-1500: 2kB |
|
S7-1200: 8kB |
|
Others: 1472B |
|
S7-300/400: 32kB |
|
|
|
|
|
|
Connection |
Connection |
Connection |
Connectionless |
|
orientated |
orientated |
|
|
|
|
|
Acknowledgment |
Acknowledgment of |
Acknowledgment of |
Only Acknowledges |
|
sending and receiving |
sending and |
sending and not |
|
of data |
receiving of data |
that it was received |
|
|
|
|
Systems |
Siemens and 3rd |
Siemens |
Siemens and 3rd |
|
Party |
|
Party |
|
|
|
|
https://support.industry.siemens.com/cs/au/en/view/26171811
Unrestricted © Siemens 2020
Page 6