The MSG Control Tag on a Logix Controller: What Each Tab Writes Into It Line_Msg.DN came true on rung 13 of a 1756-L71 and the forty DINTs the rung was guarding still held last shift’s numbers. The bit had been set by a different message — a four-element write to a capper down on rung … Read more
A Node-RED Logix tag read takes one install script, one palette install and two dialogs on a Raspberry Pi 4: Zone7_Speed from a 5069-L306ER appears in the debug sidebar as 30.0, and none of it involves typing a line of code. The node that does it is node-red-contrib-cip-ethernet-ip 1.1.3, installed from the palette manager, configured … Read more
16#0204 appears twice in the same Rockwell reference manual with two different meanings, and which of the MSG instruction error codes tables you are reading decides where you spend the next hour. In the extended error codes for error 0001 it is Unconnected message timeout. In the module fault codes it is Connection Request Error: … Read more
Produced and consumed tags stop at 500 bytes, and at 480 once the data crosses a network, because the transfer spends 20 of them on overhead. Try to produce an INT array and Logix Designer refuses: DINT, UDINT, LINT, ULINT, REAL and LREAL are the atomic types that go across on their own, and anything … Read more
Assembly instances, sizes, Comm Format and RPI for a device with no catalogue profile and no EDS file, plus the connection error codes that follow.
Wireless PLC communication done properly: choosing Wi-Fi, 900 MHz radios or cellular, RPI and timeout budgets, antennas, roaming, and link loss logic.
A repeatable PLC troubleshooting order: module LEDs, controller major faults, I/O connection status, forces, cross-reference, trends and Ethernet checks.
Set up EtherNet/IP between a Logix controller, remote I/O and a drive: RPI, unicast vs multicast, MSG paths, and the fault codes you will really see.