You buy an EtherNet/IP AC drive from Rockwell Automation. It works with your ControlLogix PLC. You later buy a different AC drive from a different manufacturer — say, Yaskawa or ABB — and it works with the same PLC too. Why? Because both drives implement the CIP AC Drive Device Profile (Device Type 0x02). They expose the same… Read More »
Twenty years ago, synchronized motion across multiple servo drives required a dedicated motion bus — SERCOS, MACRO, FireWire, or a proprietary fieldbus. The motion network ran separately from the control network because standard Ethernet couldn’t deliver the deterministic microsecond timing motion needs. Today, with CIP Motion running over standard EtherNet/IP, the motion bus and the control network are… Read More »
When a six-axis servo system has to coordinate moves across drives that may be sitting in different cabinets, on different switches, in different rooms — sub-microsecond timing matters. When a sequence-of-events recorder needs to log which fault tripped first across a network of distributed I/O — microsecond timing matters. When a process control application needs to correlate data… Read More »
Open any CIP packet in Wireshark and you’ll see paths encoded as hex bytes — 20 04 24 66 2C 67 2C 68, 20 06 24 01, 34 04 01 00 0C 00 B8 00 04 01. These are CIP path segments — the universal addressing format that tells every CIP service where to go. Class IDs, Instance… Read More »
If you have ever built a system on MQTT 3.1.1 and ended up encoding metadata into topic names or stuffing JSON envelopes inside payloads to carry information about the message, you have already felt the gap that user properties fill. MQTT 3.1.1 had no place for application-defined metadata in a message; the protocol’s headers were rigidly defined, and… Read More »
If you have ever debugged an MQTT 3.1.1 deployment where a client mysteriously refuses to connect, or where a publish silently fails to reach its subscribers, you have run into MQTT 3.1.1’s biggest weakness: it tells you almost nothing about what went wrong. The handful of CONNACK return codes are vague, most other packets carry no failure indicator… Read More »
Behind every Forward_Open is one object. Behind every Forward_Close, every Unconnected_Send, every “connection timeout,” every “out of connections” error — one object. The Connection Manager Object (Class 0x06) is the CIP object that allocates and manages all the connection resources in a device. If Forward_Open is the service, the Connection Manager Object is what answers the door. This… Read More »
When your I/O block reports “Link Down,” when error counters spike in Studio 5000, when a DLR ring takes longer than expected to converge — the data you need lives in the Ethernet Link Object, Class 0xF6. It’s the CIP object that holds every Ethernet-layer diagnostic on every EtherNet/IP device: link status, link speed, duplex mode, MAC address,… Read More »
The S7-1500 talks Modbus TCP straight out of its PROFINET port. No CP module, no license, no third-party library. You drop in two instructions — MB_CLIENT and MB_SERVER — point them at a connection structure, and you have a working Modbus link. That said, the part that trips people up isn’t dropping the block in. It’s the connection… Read More »
Every EtherNet/IP device has an IP address. Every device has a subnet mask and a gateway. Every device decides whether to get its address from DHCP, BOOTP, or static configuration. Every device that participates in multicast I/O has a multicast address range. All of this lives in one CIP object — the TCP/IP Interface Object, Class 0xF5. When… Read More »