Rockwell Studio 5000 - PLC Programming & Automation

Adding a Generic EtherNet/IP Module to the Ethernet Card: Connection Parameters and RPI

Assembly instances, sizes, Comm Format and RPI for a device with no catalogue profile and no EDS file, plus the connection error codes that follow.

Writing a Setpoint Back to the PLC from a Pi: The Handshake That Stops It Being a Safety Problem

by PLC

The write path from dashboard to Pi to CompactLogix, with the panel selector switch drawn as a hard-wired input beside the controller and no safety tag anywhere on the path

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

Safety Network Number and Signature: What Has to Match When You Replace a Safety Module

by PLC

plc programming safety network number signature replace safety module 1 plc

The 1791ES-IB8XOBV4 on the palletiser cell failed on a Sunday, the spare from stores has the same catalogue number and the same three address switches set to 21, and the yellow triangle over it in the I/O tree has not moved in forty minutes. The GuardLogix 5580 project has a safety signature, the module’s Safety … Read more

Gapping Cartons Before a Scanner: Speed Ratio, Gap Length and the Eye That Measures It

by PLC

Side view of zone 12 at 0.280 m/s, the metering belt at 0.513 m/s and the scanner belt, two 300 mm totes nose to tail before the step and 250 mm apart after it, the gap eye PE_G 2 m past the step, and the gap arithmetic for three product lengths

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

Two Zones That Disagree About Who Owns the Box: The Handshake That Restarts a Stuck Conveyor

by PLC

Zones 4, 5 and 6 in side view with the 900 mm blind length between PE4 and PE5 marked, a 600 mm carton standing 30 mm short of PE5 with every ownership bit clear, and the next carton on PE4 about to be released into it

Zone 5 is stopped, PE5 is clear, Zone[5].Expecting is 0, and there is a 600 mm carton standing 30 mm short of the beam that no zone on the line is driving. Zone 4 behind it has a carton on its eye, Owns clear, its hold timer done, and every permissive it needs to release … Read more

Restarting a Fully Accumulated Conveyor After an E-Stop Without Stalling the Line

by PLC

Plan of the twelve full zones after the E-stop, a carton on every eye and two coasted past theirs, the seconds until each zone first moves, and the five things that have to be true before Line_Running

The E-stop is reset, the safety relay is closed, every one of the twelve PowerFlex 525s on the accumulation line has S1 and S2 at 24 V again and F059 cleared from its display, and nothing moves. No fault on any drive, no alarm on the HMI, twelve zones with a carton on every eye … Read more

Sortation Verification: Proving the Carton Went Where the Logic Sent It

by PLC

plc programming sortation verification confirm eye mis sort counter 1 plc

The warehouse system’s report for the night shift said 4,629 cartons sorted, 100% to the lane the order wanted, and the lane 2 pallet had 19 cartons on it that belonged in lane 3 and a picker who found them at 06:40. The sorter had no way to know. Its scanner read the label, its … Read more

One Photo-Eye, Two Signals: Light-Operate, Dark-Operate and the Setting That Inverted Your Zone Logic

by PLC

One retroreflective 42EF with its reflector, beam made on an empty zone and beam broken by a carton, and below it the output and LED state of a light-operate J model and a dark-operate K model in each case

Zone 6’s eye came out of stores as a 42EF-P2KBB-F4, went onto the bracket in place of a 42EF-P2JBB-F4, and from the next 600 mm carton on, zone 6 reported occupied while it was empty and empty while a carton stood on it. One letter in the fifth position of the catalogue number, K for … Read more

Accel and Decel Times on a Conveyor PowerFlex 525: The Parameters That Stop F005 on Stop

by PLC

plc programming powerflex 525 decel time f005 overvoltage on stop 1 plc

The takeaway conveyor’s 25B-D010N104, a 480 V PowerFlex 525 on a 4 kW motor, ran all day and tripped F005 OverVoltage on the first stop of every shift, with the PowerFlex 525 decel time at 2.00 s, b005 [DC Bus Voltage] sitting at 812 V in the fault history, and a belt carrying forty cartons … Read more

Wiring a Pt100 into an Analogue Input and Getting Degrees Out: Three-Wire Compensation and the Open-Circuit Reading

by PLC

The Pt100 head with its three leads, the 22 m run, and the two terminal strips it lands on: IN-0/A, IN-0/B and RTN-0/C on the 1756-IR6I with the two-wire short drawn dashed, and M+, M-, I+ and I- on the SM 1231 RTD with the bridge the S7-1500 function manual describes

A Pt100 RTD input wired two-wire over 22 m of 0.5 mm² cable into channel 0 of a 1756-IR6I reads 104.1 °C in a bath that the reference thermometer says is 100.0 °C, and the same sensor with its third lead landed on RTN-0/C reads 100.0 °C. Lift lead A off the module and the … Read more

Counting Cartons at the End of the Line: Debounce, Minimum Gap and the Count That Drifts

by PLC

Side view of the takeaway end with PE_EOL 0.4 m before the palletiser infeed, a 300 mm tote, a 600 mm carton and a 1219 mm carton with the 210 mm gaps, the block and clear times at 0.500 m/s, and a strap end re-making the beam for 30 ms in the middle of the carton

A CTU on the end-of-line eye of a takeaway running 0.500 m/s read 12,480 at the end of a shift in which the palletiser stacked 12,116 cartons, and it had been drifting the same way, 2.6% to 3.4% high, for three weeks. Counting cartons was one contact and a counter, and there was nothing wrong … Read more

Speed Matching Two Conveyor Sections So Product Does Not Bunch at the Transfer

by PLC

The transfer in side view: the takeaway at 0.500 m/s handing over the nose-over to the palletiser infeed at 0.462 m/s, a 1219 mm carton bridging the gap with its nose on the slow belt, the pitch closing from 1429 to 1320 mm, the 210 mm gap becoming 101, and PE_X 0.6 m past the transfer

Two PowerFlex 525s with 42.50 Hz on both keypads were running the takeaway at 0.500 m/s and the palletiser infeed it hands over to at 0.462 m/s, and every carton that crossed the transfer between them arrived 7.6% closer to the one in front than it had left. A 1219 mm carton that left the … Read more