A list of industrial protocols and their wireshark dissectors to understand them a little bit better:
- CoAP --> Protocol Draft --> Wikipedia entry --> Wireshark dissector
- HART-IP --> Wikipedia entry --> Wireshark dissector
- GOOSE (IEC61850) --> Detailed analysis --> Wireshark dissector
- SV (IEC61850) --> Wireshark dissector
- Modbus/TCP --> Modbus specification --> Wireshark dissector
- OPC DA --> Wikipedia entry --> wireshark dissector
- Fieldbus HSE --> Detailed analysis --> Wireshark dissector
- IEC 104 --> Wikipedia entry --> Wireshark dissector
- Ethernet POWERLINK (EPL) --> Wikipedia entry --> Wirehark dissector
- Siemens S7 --> Wikipedia entry --> More info --> Wireshark dissector --> Siemens 300/400
- MMS (IEC61850) --> Wirehsark dissector
- OPC UA --> Some info --> Wireshark dissector
- Omron FINS --> https://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-omron-fins.c
- openSAFETY --> https://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-opensafety.c
- EGD (Ethernet Global Data)--> https://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-egd.c --> GE Fanuc
- DNP3 --> http://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-dnp.c
- Sinec H1 --> https://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-h1.c
- Profinet --> https://github.com/wireshark/wireshark/tree/master/plugins/profinet/
- EtherCAT --> https://github.com/wireshark/wireshark/tree/master/plugins/ethercat/
- SERCOS III --> https://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-sercosiii.c
- RTPS --> https://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-rtps.c
- TTEthernet --> https://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-tte.c
- CDT --> https://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-cdt.c
- EtherNet/IP --> https://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-etherip.c
- CIP --> https://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-cip.c
- CIP Safety --> https://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-cipsafety.c
- DeviceNet --> https://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-devicenet.c --> Allen-Bradley
- BACnet --> https://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-bacnet.c
- KNXnet / IP --> https://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-knxnetip.c
- Lontalk --> https://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-lon.c --> LonWorks-
- CANopen --> Wikipedia entry --> Wireshark dissector
- SAE J1939 --> https://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-j1939.c --> CAN
- USITT DMX512-A --> https://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-dmx.c
- BSSAP/BSAP --> https://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-bssap.c --> Bristol Babcock Inc
- Gryphon --> https://github.com/wireshark/wireshark/tree/master/plugins/gryphon
- ZigBee --> https://github.com/wireshark/wireshark/tree/master/epan/dissectors/packet-zbee.h
...and of course there are many more left...