About

Written by a process automation engineer who still works on live plant, for a Tier-1 DCS vendor. PIDSnap is tuning software built from that field experience. No photograph. Signed SS. The byline is the work.

The number that was right in one controller and wrong by sixty in another

A flow loop was sluggish, so the integral time was cut to thirty seconds. The change was typed into a controller that expressed reset in a different convention, and what was stored was eighteen hundred seconds — thirty minutes. The loop got slower, not faster. The number on the faceplate looked ordinary. Nobody caught it for weeks.

Integral time is the same quantity in every controller. It is written four ways: minutes per repeat, seconds per repeat, repeats per minute, and repeats per second. The first two are a time per repeat; they differ by a factor of sixty. The last two are repeats per time, the reciprocals, running in the opposite direction. The same thirty seconds is 0.5 minutes per repeat, 30 seconds per repeat, or 2 repeats per minute. Carry a number from one convention into a field that expects another and the loop is wrong by sixty, or inverted.

That is not a documentation footnote. It is a live-plant failure mode. A 30 that meant seconds/repeat, entered as minutes/repeat, is a factor-of-sixty error that still looks like a plausible number. A minutes/repeat value dropped into a repeats/minute field is not even the same direction. The arithmetic is trivial. The damage is not.

This is the credential. Not a resume. The mistake PIDSnap exists to stop, seen on a console rather than read in a textbook. Nothing the author could write about themselves would tell you as much about whether the tool is worth trusting as that one number does. The full conversion is in why a 30-second reset became 30 minutes.

Why PIDSnap refuses work it cannot do

Most bad loops are not tuning problems. Valve stiction. Backlash. An output already sitting on its stop. Selling a session against those is charging for a fix that cannot land.

The pre-flight check runs first, in deterministic code, before any constant is touched. If the trend or the configuration says the problem is mechanical, PIDSnap says so and does not take the money. It will not tune a stuck valve because you asked it to. Rejecting a bad problem is the product behaving correctly. How that refund works is on the refunds page, not buried in a footer.

What it will take on is the arithmetic you should not be doing in your head at a live console. It reads the photograph, asks you to confirm the values off your own faceplate, and computes the next step in your plant's units and algorithm form — once, in code, and checked. It never originates a tuning number. The value it shows is the value you confirmed, multiplied by a step factor, converted into the convention on that controller.

Air-gapped on the plant side

PIDSnap connects to zero plant networks. It does not sit on the DCS. It reads no historian. It writes nothing to any controller. The only input is optical: a photograph of a trend screen and a faceplate, taken on a phone that does not need to be on the control network. If it is not in the picture, it is not in the tool.

That is the OT boundary. A web application that pulled tags from your historian would be a different product, and a different argument with your cybersecurity group. This one has no plant interface to argue about. What happens to the photographs after they leave the phone is on the security page, stated as what the code does.

Who is behind it

The author publishes as SS because they are employed in the industry, on the vendor side of the console. A named page about the software, written by someone still on a DCS payroll, is a conflict. Silence without a reason would read as evasion. The reason is stated. The operator of the service is named in the terms.

The knowledge that matters here is the field mistakes: reset units, stiction mistaken for hunting, a saturated valve sold as sluggish tuning. That is what the pages are built from. Questions, corrections, or a plant-floor story of your own: write to support.

What it is

A software service that computes the next step in your plant's units and algorithm form. It never originates a tuning number. You type the value it shows you. The decision to act is yours, under your own management-of-change process. The disclaimer on every page says so.

— SS