PLC Programming & Automation Forum - Recent Posts

RE: 1734-AENTR display keeps restarting and the Point I/O drop faults a few times a shift

plctr_mod — Tue, 22 Sep 2026 21:02:57 +0000

Marking solved. That display is a status line, not a fault code.

RE: STEP 7 V5.5 says object not found with 256:31 and I cannot find that number anywhere

hanab — Tue, 22 Sep 2026 19:02:58 +0000

Good one to write on the cabinet door. Nobody ever remembers the 256 family exists.

RE: CIP Generic MSG to a PowerFlex 525 comes back 16#0005 every time

billr — Tue, 22 Sep 2026 19:02:58 +0000

Everything in that dialog is hex. Learned that one the same way.

RE: TON preset for a 30 day filter timer overflows, what do people use instead

kiran_s — Tue, 22 Sep 2026 19:02:57 +0000

It will fire. Nothing wrong with that on a filter.

RE: Modbus TCP gateway drops four seconds at a time since a remote I/O block was swapped

boris_h — Tue, 22 Sep 2026 19:02:57 +0000

My wrong guess cost you a block. Decent spare now though.

RE: 1734-AENTR display keeps restarting and the Point I/O drop faults a few times a shift

petek — Tue, 22 Sep 2026 19:02:57 +0000

Meter on the terminals overnight on min max and the minimum came back 17.8V. Watched it sag this morning every time the dust extractor contactor pulls in, roughly every twenty seconds while the bagger runs.

The adapter, the field wiring and both extractor coils all feed off one small 24V supply somebody fitted years ago. It was never the network. It was browning out and running its display sequence again from the top, and I was reading the catalogue number off a module that had just come back up.

Adapter is on the 1606 control supply now, own pair. Two shifts, no triangles. I still can't say why it ran a whole year first. Thanks boris_h, and northbay for telling me what I was looking at.

RE: TON preset for a 30 day filter timer overflows, what do people use instead

wandak — Tue, 22 Sep 2026 18:52:47 +0000

Put the clock version in on Thursday. GSV WALLCLOCKTIME into a 7 element DINT array, the date written to a retentive tag when the operator presses Filter Changed, and a compare on an hourly basis against that plus 30 days.

The original problem was me assuming a TON preset was just a big number. It's a signed DINT in ms, so 24 days 20 hours is the ceiling and the MOV let me sail straight past it into negative without a word.

Still not sure what happens if someone sets the controller clock forward while the timer is pending, I expect the reminder just fires. Thanks jcasey, kiran_s and louk.

RE: TON preset for a 30 day filter timer overflows, what do people use instead

louk — Tue, 22 Sep 2026 18:42:51 +0000

Then don't count, compare. GSV WALLCLOCKTIME into a DINT array at the point somebody presses the filter changed button, store the date, and every hour compare today against stored plus 30. The controller's clock keeps running on the battery through an outage and the comparison doesn't care how long you were off.

Counting suits a machine that only matters while it's running. A calendar job wants the calendar.

RE: TON preset for a 30 day filter timer overflows, what do people use instead

wandak — Tue, 22 Sep 2026 18:33:26 +0000

That's the shape I was after. One thing though, this station drops power more often than I'd like, maybe a couple of hours at a time when the co-op has a line down.

A minute counter that loses its place every outage is going to drift and the reminder ends up meaningless by the third month.

RE: TON preset for a 30 day filter timer overflows, what do people use instead

louk — Tue, 22 Sep 2026 18:22:58 +0000

Cascade it and stop fighting the instruction. One TON with a 60000 ms preset that resets itself on DN, feeding a CTU with a preset of 43200. Counter DN is your 30 days, the accumulator tells you how many minutes in you are, and both numbers stay small.

We had these on filter and belt reminders on a dozen sites and none of them ever needed better than a minute of accuracy.