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The thing that costs money

The expensive part of PLC work is not writing it

Every controller we have ever taken over was working when we found it. That is not the problem. The problem is that the person who wrote it has left, the program has no comments, the tag names are abbreviations only they understood, and the copy on the laptop in the control room is two revisions behind what is actually running.

At that point any change, however small, starts with reverse engineering. On a pump station that means somebody sitting with a laptop working out why a permissive exists before they dare remove it. On a substation it can mean not touching it at all, which is how plant ends up frozen around software nobody understands.

So the useful question when buying PLC programming in the UAE is not who can write it cheapest. It is what you will be holding at handover, and whether a different engineer could pick it up in a morning.

Who writes it

Three ways PLC logic gets written, and what each leaves behind

The equipment supplier

The pump, chiller or package skid vendor supplies the controller pre programmed. Convenient, and often locked. Ask before purchase whether you receive the source and the tool, because after delivery you have no leverage.

A programming house

A specialist writes to your functional design specification. Good code, usually well structured. They are rarely on site during commissioning, so the inevitable field changes get made by somebody else and frequently never make it back into the master copy.

The integrator who commissions it

The same party writes the logic, wires the panel, commissions the loops and stands at site acceptance. Field changes go back into the master because the same people own it. This is how we work, and it is the reason our as built software matches the plant.

Handover

What to demand at handover, in writing

  • Commented source code, not a compiled or password protected download
  • The programming software and licence, with the version recorded
  • A tag list with descriptions, addresses, engineering units and alarm limits
  • A functional description of every interlock and permissive, in plain language
  • Confirmation that the master copy matches what is running, dated and signed after final commissioning
  • A backup of the controller and the HMI taken on the last day, not the first
  • Any passwords, keys or dongles, held somewhere other than the contractor's office
  • A written note of every field change made during commissioning and why

Track record

Controller work delivered

Irrigation PLCs and RTUs, park pumping stations, and the drive and motor replacement that came out of a controller reaching end of support.

See all 19 delivered projects →

Platforms

Controllers and tools we work with

  • Schneider Electric
  • Siemens
  • Allen Bradley
  • GE Vernova
  • IEC 61131 languages
  • Modbus
  • DNP3
  • OPC UA

Method

How the logic gets proved

  1. Functional description before code

    What the plant should do, written in language the operator and the client engineer can both check. Disagreements are cheap at this stage and expensive after commissioning.

  2. Structured, commented code

    Consistent tag naming, reusable blocks, and comments written for the engineer who arrives in ten years. This costs a little time once and saves it repeatedly.

  3. Simulated testing

    Logic driven from simulated inputs in the workshop, so interlocks and alarms are exercised without waiting for plant availability or risking equipment.

  4. Loop check and point to point

    Every input and output proved from the field device through the controller to the screen. Slow, and there is no substitute for it.

  5. As built software, dated

    After the last field change, the master is updated, backed up and handed over with a date on it. This is the step most often skipped and the one you will care about later.

Common questions

Questions we are asked about this

Which PLC brand should we specify?

Usually the one your maintenance team already carries spares and skills for, unless the application needs something specific. Standardising across a site is worth more than picking the theoretically best controller for each job, because it decides how quickly a fault gets fixed at two in the morning.

Can you modify a PLC program written by someone else?

Yes, and much of our work is exactly that. If the source is available it is straightforward. If only a compiled program is on the controller, the honest answer is that it becomes a survey job first, and we price that separately rather than hiding it in the change.

What is the difference between PLC programming and SCADA configuration?

The PLC decides what the plant does, including when the link to the control room is down. SCADA presents it and lets an operator intervene. A plant with good logic and a poor SCADA is inconvenient. A plant with a beautiful SCADA and poor logic is dangerous.

Do you provide the source code at the end?

Yes, commented, with the tag list and the programming tool version recorded. We regard a client who cannot have another contractor work on their own plant as a problem rather than a commercial advantage.

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Emailinfo@almafor.com
Sales+971 55 954 5801
Technical+971 55 954 5802
Office+971 2 665 5540
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Abu Dhabi, United Arab Emirates

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