Forum

marekw
@marekw
New Member
Joined: Jan 20, 2025
Last seen: Sep 19, 2026
Topics: 2 / Replies: 12
Reply
RE: MicroLogix 1400 CTU counts two or three per bag from a photoeye, count 15 percent high

Both, then. Tilt the eye as carl says and keep the timer, because any eye will give you a short edge sooner or later. Final rung: I:0/3 into a TON, T...

3 hours ago
Reply
RE: 4-20 mA level signal noisy since a PowerFlex 755 went in

A soft starter does not switch at 4 kHz. Pull the filter.

5 hours ago
Reply
RE: 1769-IQ16 input chatters after wiring it in parallel with a 1734-IB8S safety input

Yes. Put a scope on that wire, or a fast meter, and you'll see 24V with a short drop every so often. That's the IB8S pulling T0 low for a moment and c...

5 hours ago
Reply
RE: PID_Compact stays Inactive on an S7-1200, State 0, Output never moves

Before the software, one check: with the heater forced on from a watch table, does the Pt100 climb? If yes the loop is proved and it is only the block...

6 hours ago
Reply
RE: PID_Compact output twitches between 40 and 60 percent as soon as I add derivative

Trend the PV on its own for a minute at 100 ms, nothing else changing. How much does it move when the process is sitting still? And the transmitter, 4...

7 hours ago
Reply
RE: Modbus RTU RS-485 to six meters on a MicroLogix 1400, timeouts on the far three

400 ft is nothing for RS485, a kilometre works at 19200. Before you buy a repeater: with the master idle, what DC voltage do you read A to B at meter ...

8 hours ago
Reply
RE: MicroLogix 1400 CTU counts two or three per bag from a photoeye, count 15 percent high

No. A CTU counts the rising edge of its rung, one per false to true, however many scans the rung then stays true. So the eye's giving you more than on...

12 hours ago
Reply
RE: MB_CLIENT on S7-1200 reads the wrong registers from a power meter, values shifted

Before the block, prove the meter. With a laptop Modbus tool, read holding register 3000 and see what comes back. If the tool shows 231 V at 3000 and ...

15 hours ago
Reply
RE: 4-20 mA level signal noisy since a PowerFlex 755 went in

Both ends grounded turns the shield into a conductor between two grounds that are not at the same potential when a 755 is switching. Current flows on ...

22 hours ago
Reply
RE: 2-wire prox keeps an S7-1200 input on with nothing in front of it

A 2 wire sensor has no separate supply. It powers itself through the load, your input, so even when off it passes a small current to keep its electron...

3 days ago
Reply
RE: S7-300 SM 331 level scaling shows only 0, 25, 50, 75 percent, DINT maths

Before the maths, prove the loop. Put a meter in series with the transmitter. What mA at the level you've got right now, and at the same moment what d...

3 days ago