Every PLC and HMI tutorial on plctr.com: project setup, ladder and structured text, communication, troubleshooting and commissioning, written from the plant floor.
An MQTT Broker for Plant Data: Topics, QoS, Retained Messages and Last Will The topic string plant2/pack/carton1/tr14/belt1/amps is 42 bytes. The float it carries is four. Every publish of the motor current on one belt of the carton transfer therefore spends ten times as much on saying where the number came from as on the … Read more
Scaling a Kinetix Axis in Real Units: Position Units, the Conversion Constant and the Gearbox A new Kinetix axis is scaled one Position Unit per motor rev, at 1,000,000 Motion Counts per rev, and on Unlimited travel that axis rolls its position accumulator over after 2,147 revolutions. The motion runs through the rollover perfectly smoothly. … Read more
Tuning a Kinetix 5700 Axis: Load Ratio, Bandwidth and the Autotune That Lies Loop Response on the General page of a Kinetix axis is a three-item dropdown, and on a drive with the default 1.5 ms model time constant it moves the position loop between 8.2 Hz and 101.7 Hz. That is a factor of … Read more
Driving a Motor from a ControlLogix: From a Rung to a Turning Shaft on a Kinetix 5700 A 2198-D032-ERS3 inverter, a VPL-B1303C motor on one Hiperface DSL cable, and a 1756-L83E that has never carried a motion group. Two rungs will turn that shaft — an MSO and then an MAM — and neither is … Read more
MCD and MCCP: Changing the Speed of a Move in Flight, and What MCCP Actually Calculates An MCD that lowers Decel from 1000 mm/s² to 200 mm/s² 1.72 seconds into an absolute move catches the axis at 391.6 mm with 131 mm/s still to lose. Stopping at the new rate takes 42.8 mm and only … Read more
Arrays, UDTs and Structures Over OPC UA: What the Client Actually Sees Insert one DINT called Jam_Count into the TR14_Belt user-defined type, put it after the State member where it belongs logically, and download to the 1756-L83E. Fault_Code moves from byte 4 to byte 8, and Starts, Run_Seconds, Speed_mps, Motor_Amps and Last_Fault_S each move four … Read more
MAG and Gearing Two Axes: The Ratio, the Slave, and What Happens on a Fault A MAG with a Ratio of 0.5 and Clutch enabled, fired at a slave whose master is already running at 600 mm/s, ramps the slave to 300 mm/s in 0.30 seconds at 1000 mm/s² and leaves it permanently 44.9 mm … Read more
MAH and Homing a Kinetix Axis: The Switch, the Marker, and the Home That Lands in the Wrong Place A home-to-switch-then-marker sequence at a Home Speed of 25 mm/s and a Home Return Speed of 5 mm/s takes just over four seconds on a 2198-D032-ERS4 axis, and 1.5 of those seconds are spent crawling back … Read more
Browsing an OPC UA Server Against a Static Tag List: Which One, and When Each Is Wrong Node i=2255 is the NamespaceArray, and one Read of it is the single most-skipped call in industrial OPC UA. Skip it and you type ns=3 into a client, which works for a year and then reads the wrong … Read more
MAM Against MAJ on a Logix Axis: A Move That Ends and a Move That Does Not An absolute MAM to 400.000 mm at 250 mm/s, with 1000 mm/s² either side of the cruise, sets its .PC bit 1.83 seconds after the rung goes true. An MAJ at 120 mm/s on the same axis sets … Read more
MSO, MSF and MASD on a Logix Axis: Enabling It, Dropping It, and the One That Opens the OK Contact An MSO against a 2198-D032-ERS4 axis sets ServoActionStatus and DriveEnableStatus, and it does not set its own .DN bit in the scan that fired it. On a 2 ms coarse update period the drive answers … Read more
The Motion Group and the Coarse Update Period: What Happens When You Ask for Too Much Bit 2 of MOTION_GROUP.GroupFault is GroupTaskLoadingFault, and the motion instruction reference describes it in plain words: the group coarse update period is too low, and user application tasks are not getting enough time to execute. That is a 1756-L84E … Read more