A 1756-OF8 is a 0…20 mA module, and at full counts it puts out 21.29 mA. Nothing in the hardware knows that the positioner on the end of the wire wants 4 mA for closed and 20 mA for open, or that 0 mA on an air-to-open valve is the same as closed and 21 … Read more
On a 1.5 m zone pitch at 0.28 m/s, a 600 mm carton is invisible to both photo-eyes for 3.2 seconds of its journey between them. An upstream zone whose release permissive is nothing more than “the next eye is clear” will use that window to send a second carton, and the two of them … Read more
Time it with a stopwatch before you type anything into the preset: the longest carton you run, crossing the photo-eye, on the slowest zone. A 1219 mm carton at 0.28 m/s sits on that eye for 4.35 seconds, which is why the 2000 ms that came across with the copied project trips every time the … Read more
A 1756-IF8 analog input in integer mode lands on roughly -20,030 counts at 4 mA and 30,920 at 20 mA, which are not numbers anybody memorises. If the value in front of you is 3277, the card in the rack is a 1769-IF4 or 1769-IF8 running the Scaled-for-PID data format, and none of the 1756 … Read more
200 tags at one row a second is 17.28 million rows a day, and at the 47 bytes a row that SQLite measured on this machine for a typed, indexed table, that is 814 MB a day and a 32 GB card full in 32 days. The same 200 tags logged on change, with a … Read more
A CPU 315-2 PN/DP with 6ES7315-2EH14-0AB0 on the label maps to a CPU 1515-2 PN, 6ES7515-2AM01-0AB0, in the Siemens migration guide’s CPU table, and the S7-1500 migration does not happen in one move. It happens in two, the second of which is a right-click on the old CPU in the device view called Migrate to … Read more
Step 2 of a two-step TIA Portal GRAPH sequencer on a CPU 1515-2 PN has been active for 4 minutes 12 seconds by its own S2.T, the transition below it has been satisfied for the last 40 of those seconds, and the sequencer is still sitting on step 2. The heater that step 2 drives … Read more
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
A know-how protected OEM block will not open. What TIA Portal still lets you do with it, why the compile error sits in your call, and how to clear it.
Write an AHU sequence on a CompactLogix: damper minimum position, supply fan VFD, chilled water PID, economizer changeover, compressor staging and BACnet.
Build PLC predictive maintenance on hardware you own: vibration and motor current inputs, runtime hours, moving averages, baselines and alarm levels.
How the BPCS, the SIS and the package PLC split the work on a batch reactor, with a cause and effect matrix, cascade temperature control and IS barriers.