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
At 02:30 on Sunday 25 October 2026 a logger in Berlin writes a row, and sixty minutes later it writes another row stamped 02:30, and the trend viewer draws the second hour on top of the first. Meanwhile the controller it reads from keeps its own idea of the time as a LINT of microseconds … Read more
A pusher divert with its trigger eye 1.20 m upstream and a 2780 ms delay in the program was diverting 97% of the 600 mm cartons and 61% of the 300 mm totes, and every tote it missed was hit on its back corner and spun onto the takeaway sideways. The 2780 ms was right … Read more
Two cartons released 1.1 seconds apart from line A and line B arrive at a 30 degree merge at the same moment, because line A’s release eye is 1.3 m from the junction and line B’s is 1.7 m, and 0.4 m at 0.28 m/s is 1.4 seconds. The rung that let that happen was … Read more
A 42EF retroreflective eye bolted 150 mm back from the discharge roller of a 1.5 m zone stops a 600 mm carton with 750 mm of zone still behind it, and stops a 1219 mm carton with 131 mm. Move the same eye to 50 mm from the discharge and the first carton overshoots into … Read more
Siemens gives you a Retain checkbox and a published memory budget. Rockwell gives you neither. Here is what each one really keeps, and how to check it.
Store a ControlLogix project to a 1784-SD2 card, pick the Load Image setting you need, and what an upload or a card restore will not give back at 3am.
Four lines of Python on a Raspberry Pi 4 read a CompactLogix tag – a REAL out of a 5069-L306ER – and nothing at either end is licensed. pycomm3 1.2.16 speaks EtherNet/IP to TCP port 44818 itself, which takes the OPC server, the Windows box it used to live on and the licence out of … Read more
On a 1.5 m zone pitch at 0.28 m/s, a 600 mm carton is invisible to both photo-eyes for 3.2 seconds of its journey between them. An upstream zone whose release permissive is nothing more than “the next eye is clear” will use that window to send a second carton, and the two of them … Read more
Time it with a stopwatch before you type anything into the preset: the longest carton you run, crossing the photo-eye, on the slowest zone. A 1219 mm carton at 0.28 m/s sits on that eye for 4.35 seconds, which is why the 2000 ms that came across with the copied project trips every time the … Read more
A pycomm3 write of 95.0 to Line4_SP on a CompactLogix comes back to the Raspberry Pi with no error, and the line is now running at 95 % because nothing between the driver and the tag asked whether it should. A read-only logger becomes a control path the first time somebody puts a slider on … Read more
A 300 mm tote leaving zone 12 at 0.280 m/s onto a metering belt running 0.513 m/s arrives at the scanner 250 mm behind the tote that left in front of it, and a 600 mm carton on the same two belts arrives 499 mm behind its neighbour. Neither number has a timer in it: … Read more