UDT - PLC Programming & Automation

PLC Program Documentation That Survives a Night Call

September 12, 2026February 8, 2024 by PLC

Ladder rung showing a filler conveyor motor start/stop with seal-in and descriptive tag names L3_FIL_Start_PB, L3_FIL_Stop_PB, L3_FIL_Mtr_OL and L3_FIL_Mtr_Run

Tag naming, rung comments, UDT and AOI descriptions, pass-through and L5X exports that keep a Studio 5000 or TIA Portal project readable years later.

RFID PLC Integration: Read and Write Tags from Ladder

September 13, 2026January 30, 2024 by PLC

Timing chart of an RFID read cycle: the trigger bit, the reader busy bit, the done bit, and the UID landing in the UDT before the trigger is cleared

Pick HF or UHF, connect the reader over EtherNet/IP or Modbus, map the data into a UDT, and run a trigger, busy, done handshake that does not drop reads.

PLC MES Integration: Tags, Handshakes and Work Orders

September 12, 2026January 17, 2024 by PLC

Timing chart of an MES to PLC work order handshake showing Request from the MES, Ack from the PLC, Done when the order is latched, and both bits clearing after Request drops

What MES really needs from the controller: OEE counters, downtime reason codes, a work order UDT, a request and acknowledge handshake, an OPC UA bridge.

User Defined Datatype UDT Usage Examples in RSLogix 5000 PLC

May 2, 2021July 19, 2020 by Admin

User defined data type ( UDT ) Examples in RSLogix 5000 program, how can create a plc program using UDT, start to learn advance plc programming via UDT.