Every PLC and HMI tutorial on plctr.com: project setup, ladder and structured text, communication, troubleshooting and commissioning, written from the plant floor.
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
Power up the cell and the 1734-AENT on Fa1/5 sits in module fault for about thirty seconds, every single time, then clears itself and runs all week without a hiccup. The adapter is fine, the drop cable is fine and the RPI is fine. That port spends its first 30 s after link-up walking through … Read more
Module Fault 16#0010: Mode or State of Module Does Not Allow the Object to Perform the Service The Connection tab of the module properties reads Module Fault 16#0010, and the sentence beside it says the mode or state of the module does not allow the object to perform the requested service. The general instructions reference … Read more
Unicast or Multicast on an EtherNet/IP I/O Connection: the Checkbox and What It Decides Module fault 16#0106 appeared on the second controller’s listen-only copy of a 1734-AENTR drop, and the string underneath it reads “Module owned and configured by another controller. Module may accept only one connection if Unicast is used.” The owning controller had … Read more
The Connection Timeout Multiplier on a 1756-EN2T: What It Buys and What It Hides A rack-optimised connection through a 1756-EN2T at a 100 ms RPI rides out 400 ms of total silence before the module goes yellow in the I/O tree. At a 10 ms RPI the same connection faults after 160 ms, not after … Read more
The CIP Generic MSG on a Logix Controller: Service Code, Class, Instance, Attribute Four boxes on the Configuration tab of the Message Configuration dialog, and the manual that tells you what to type in them is a different manual for every device you point the message at. Service Code 4B, Class 342, Instance 0, Attribute … Read more
Modbus TCP from a 1756-EN2T with the Socket Object: the Five Messages, the Frame, the Byte Order A 1756-EN2T in slot 3 at 192.168.1.10, a third-party power meter at 192.168.1.40 answering on port 502, and a MSG instruction that returns 16#00ff with an extended code of 16#0000_0046 on every attempt. Nothing on that network is … Read more