Every PLC and HMI tutorial on plctr.com: project setup, ladder and structured text, communication, troubleshooting and commissioning, written from the plant floor.
Write a torque reference into DINT 1 of a PowerFlex 755’s output image and the drive will run at that many hertz. DINT 1 is the Reference, it is a 32-bit REAL, and 750COM-UM001 says plainly what it scales to: drive speed, in whatever P300 [Speed Units] is set to. There is no torque word … Read more
Fault 64 on a PowerFlex 755 reads Drive OverLoad on the HIM, and the first move most people make is to open the motor overload group and start editing P413 [Mtr OL Factor]. That is the wrong fault. A PowerFlex 755 fault 64 is P940 [Drive OL Count] arriving at 100 %, and P940 counts … Read more
The bagger came back with 0.0 in every recipe setpoint at 06:10, with nobody at the HMI and no download on the log. The only change on that shift was a program that had been inhibited while somebody edited it and then put back in, and the initialisation rung inside it — one XIC on … Read more
A 20-750-S seated in port 4 of a PowerFlex 755, SP and SE landed on separate contacts of a 440R-D22R2, twenty-four volts measured on both pairs, and the drive faults the moment the contactor closes. The SAFETY enable jumper is still on the main control board, where it ships from the factory, and the manual … Read more
Four guard doors on a packing cell, a Trojan T15 tongue switch on each, 440K-T11390, all four pairs of contacts daisy-chained into one 440R-D22R2 relay, and the calculation for that stop function will not go past PL c. Every switch in the chain has its two direct-opening N.C. contacts, the wiring matches the drawing, and … Read more
Reading a CompactLogix Fault: The Four Places the Controller Says What Broke I/O Fault Local:2 #0203 Connection Timeout scrolls across the front of a CompactLogix 5380 for a few seconds and then the display moves on to the project name and the IP address. That one string is four separate pieces of information, and on … Read more
When the 1734-IB8S Will Not Run: Reading the Diagnostics First MS flashing green on a 1734-IB8S means the device is in the Idle or Standby state, and the recommended action printed next to it is to configure the module and establish a connection. Nothing about the module is broken. It has powered up, passed its … Read more
Scaling a 4-20 mA Temperature Transmitter on a CompactLogix 5380 Put Low Signal 4 mA, High Signal 20 mA, Low Engineering 0.0 and High Engineering 250.0 into a 5069-IF8 channel and Local:2:I.Ch00.Data arrives at the controller as a REAL already in degrees Celsius. There is no scaling rung, no raw count, and nothing for a … Read more
Driving a 24 V Solenoid from a 1769-OB16: Leakage Current and the Bleeder The 1769-OB16 specification table puts off-state leakage current at 1.0 mA maximum at 26.4V DC, and the footnote underneath tells you what to do about it: a 5.6 kΩ, 1/2 W loading resistor in parallel with your load. For a 24 V … Read more
The guard door opens once and gets recorded twice: 06:41:12.310 in the Logix log, 06:41:12.650 in the S7-1500’s diagnostics buffer. The two controllers are eight metres apart on the same machine, both nominally synchronised, and the gap is a third of a second every time you look. Neither clock is broken. The Logix side is … Read more
A 5069-L320ER comes out of the box with no IP address, both Ethernet ports DHCP-enabled and firmware revision 1.xxx on it. Set the address first and then flash it to 29.011 or later, and the controller quietly moves itself into Dual-IP mode, applies the address you just typed to port A2 instead, throws away the … Read more
The 1734-AENT drops out for roughly six hundred milliseconds once a shift, never twice in the same hour, and the controller log says the same thing every time: the connection timed out. That sentence tells you the connection stopped. It does not tell you which end stopped it, and while you do not know that, … Read more