I/O Addresses:Quick Access to Remote I/O
People in the field need to know where a signal is wired: which remote panel, which card, which bit. The app brings the addresses of several plants together, and the control room, far from there, answers in minutes.
- Role
- Author, during my control and automation engineering internship
- Period
- 2025 – Feb 2026
- Status
- completed
- Industrial automation
- Power Apps
Plain explanation
The problem
In a plant, every signal from a piece of equipment, such as a sensor or a switch, runs on a wire to a cabinet in the field. When a signal disappears from the screen, or before working on a piece of equipment, the person there needs to know exactly where that wire is connected: which cabinet, which module and which point.
That person asks the control room, which is far away. And the control room had to open one system after another, each plant recording the address its own way, in between shutdowns and other priorities. The answer took about 24 minutes on average, with the person who asked standing in the field, often next to an open panel or to moving equipment.
What it does
- Puts everything in one place
The addresses of several plants, once scattered across several systems, become a single base in one format.
- Finds it by the signal's code
The control room picks the group of plants and types the signal's code; the list narrows with each letter, on a phone or a computer.
- Shows the address piece by piece
Instead of a cryptic code, the app shows the address in named fields, down to the cabinet, the module and the exact point of the wire.
- Prints the whole module
A button opens the list of every point on the module, each with its signal, ready to print.
What changes
- Before
- 24 min
- After
- 3 min
The person in the field gets the answer in minutes and spends less time standing in a hazardous area, waiting.
The control room and the automation analyst get back the time they spent hunting for addresses. The control room itself checked the app's addresses, and the project was registered in the continuous improvement program (Kaizen).
And the same approach can serve other lookups that today depend on someone searching through several systems, such as a piece of equipment's spare part or a panel's wiring diagram.
Technical explanation
Problem, improvement and result
- Problem
- The I/O addresses of several plants were scattered across several systems (the process screen, the controller program, the search, the hardware tree), each in its own format, and in the program the address appears in a cryptic form, such as IX2.5.4.6. When the field asked the control room for a signal's remote panel, card and bit, the control room started from the code and opened one system after another, in between shutdowns and other priorities: the average wait was close to 24 minutes.
- Improvement
- The I/O addresses from each system, across several plants, were exported and put into a single format, split into fields: CPU, Profibus master, Profibus node, remote panel, card, bit, description and signal. That base feeds a Power Apps app on phones and computers: you pick the group of plants, its base loads (thousands of rows), the search by code narrows with each letter, and the app shows the address with the bit highlighted and the report for the whole card, ready to print.
- Result
- According to the control room's call records, which keep the time from each request from the field to the answer, the average wait dropped from about 24 to 3 minutes, eight times less. In the first period of use, the control room checked the app's addresses, and they were correct. The project was validated and registered as a Kaizen.
Evidence
Average wait from 24 to 3 minutes
From the control room's call records, which keep the time from each request from the field to the answer, before the app and in the period when the control room started using it.
Measured.
Addresses checked
In the first period of use, the control room itself checked the app's addresses, and they were correct.
Measured.
Registered as a Kaizen
Validated and registered in the continuous improvement program.
Measured.
What an I/O address is
Every signal in the plant has a code, such as SN1047, and a description, such as “belt misalignment switch”. The signal’s wire runs to a cabinet in the field, the remote I/O panel, which has its own name (RM203, for example). The remote panel connects to the controller over a fieldbus, Profibus: the network master sits in the controller, and a node of it sits in the remote panel. Inside the remote panel are the cards, modules that receive or send signals, each in a slot. Each card has several connection points, and the team calls each one a bit (“bit 6”).
In the controller’s program, the signal’s location is written in a short, cryptic form, such as IX2.5.4.6. The I means input and the X, an on/off signal; each number is a level, from top to bottom, like a tree. The app shows the same location split into named fields:
| Field | Example (made up) | What it is |
|---|---|---|
| CPU | 07 | the controller that runs the logic |
| Profibus master | 2 | the controller module that drives the fieldbus |
| Profibus node | 5 | the remote panel’s communication board, its address on that network |
| Remote panel | RM203 | the name of the cabinet in the field |
| Card | 4 | which slot of the remote panel holds the card |
| Bit | 6 | the point on the card where the wire comes in |
| Description | Belt misalignment switch | what the signal is |
| Signal | SN1047 | the code you search by |
With these fields, the person in the field goes straight to remote panel RM203, finds card 4 and measures at bit 6.
The problem
People in the field, operators or maintenance technicians, need this address: when a signal does not show up on the control room’s screen and the wire has to be traced to the card, or to check a signal before working on a piece of equipment. The question goes to the control room, by message or by phone, because the control room is far from the operation.
On the other side, the answer was scattered. The control room started from the code and opened one system after another until it found the address: the process screen, the program, the search, the hardware tree. Each system, in each plant, wrote the address its own way, and the control room also handles shutdowns and other priorities. The average wait was close to 24 minutes, with the person who asked standing in the field, often next to a panel or to moving equipment.
How it works
I downloaded the I/O addresses from each system, across several plants, and put them all into a single format. That base feeds a Power Apps app that opens on phones and computers. On the home screen you pick the group of plants, and that group’s base loads, thousands of rows. In the search, you type the signal’s code, the list narrows with each letter, and you tap the item. The app shows the address already split into fields, with the bit highlighted, and a button opens the report for the whole card, with every bit, each with its signal and description, ready to print.
The answer that goes back to the field is short: “remote panel RM203, card 4, bit 6”. The search that went through several systems became a single lookup.
The result
With the app, the control room started answering in minutes: according to the control room’s own call records, the average wait dropped from about 24 to 3 minutes. In the first period of use, the control room checked the app’s addresses, and they were correct. The project was validated and registered as a Kaizen.
That time gain turns into two gains:
- Less time in hazardous areas. The person asking is in the field, often next to an open panel or to moving equipment. The faster the answer arrives, the less time they spend standing there, waiting.
- More engineering time. Every lookup that no longer takes tens of minutes gives the automation analyst back the time spent hunting for addresses.
The next step
Bring the same lookup to the people in the field. With the app on the phones of operators and maintenance crews, the address comes out on the spot, without going through the control room, and the control room is free for what only it can solve.
In the same period
During the same internship, I also built apps for downtime alerts and event logging, with SharePoint and Power Automate, and dashboards in Power BI.
How it works
From the field's question to the address, in a single lookup.
- Question
Someone in the field messages or calls the control room, far from there, with the signal's code.
- Plants
In the app, the control room picks the group of plants, and that group's base loads, thousands of rows.
Power Apps - Code
You type the signal's code, the list narrows with each letter, and you tap the item.
- Address
The app shows the address split into fields, from the CPU down to the bit, with the signal's description.
- Answer
The control room answers with the remote panel's name, the card and the bit.
3 min on average
Limits
- The app covers the plants and systems whose addresses were brought into the base; each new plant comes in through the same format.
- The next step is to bring the same lookup to operators and field crews, on their phones, so they find the address on the spot, without going through the control room.
Today and next
Today
Built during my internship and registered as a Kaizen. The next step is to bring the same lookup to operators and field crews, so they find the address straight on their phones, without having to ask.
The images are illustrations. The cover and the remote I/O cabinet are this portfolio's 3D scene; in the video, the app's screens are a mockup that follows its flow, with made-up plants, codes and addresses.