[Feature Request]: Modbus TCP connection pooling

[IsmoLeszczynski]

What would you like to happen?

When using Modbus TCP gateways, the gateways can aggregate multiple Modbus devices using unit ids. Such gateways unfortunately also seem to sometimes have limits on how many TCP connections can be active at the same time, due to which forming a connection per unit id is not feasible. Is there a way in PLC4X to share the TCP connection between different connection strings? I know of the connection cache, but it caches per connection string, which is different per unit id in this case.

Programming Languages

• plc4j
• plc4go
• plc4c
• plc4net

Protocols

• AB-Ethernet
• ADS /AMS
• BACnet/IP
• CANopen
• DeltaV
• DF1
• EtherNet/IP
• Firmata
• KNXnet/IP
• Modbus
• OPC-UA
• S7

[chrisdutz]

You should have a look at our connection cache: https://plc4x.apache.org/plc4x/0.13.0-SNAPSHOT/users/tools/connection-cache.html This should be a general purpose solution for your problem for all PLC4X drivers.

[IsmoLeszczynski]

Thanks for the reply, I was wondering how to make use of that with different unit ids, but then I noticed I somehow skipped a line in the Modbus documentation where the unit id can be given per Modbus address. Apologies for the hassle!

[chrisdutz]

No need to appologise :-)