In this guide 6 sections
Ask who buys and owns the devices. Find out who holds the data and source code. Find out what happens when the internet drops, which protocols get read, how readings are checked and who supports sensors after commissioning. Written answers to these six questions separate a team that has worked on a shop floor from one that has not.
Who owns the devices, the data and the code?
Start with ownership. It is the cheapest question to ask. Gateways, sensors and panels may be bought by you, leased, or billed as a subscription. Each choice changes what happens on the day you part ways with the vendor.
Then ask where readings are stored and who holds the admin login. Ask whether you receive the source code, the database export and the cloud account, or only a dashboard link. Get it in writing. A partner who hesitates here is telling you something.
Short answers are best. “You own it” beats a paragraph of conditions.
- Purchase, lease or subscription for gateways and sensors
- Owner of the cloud account and the admin login
- Source code and database export on request
- Notice period and handover steps on exit
What happens when the internet drops?
Plants lose connectivity often. A gateway in a pump house or a poultry shed may sit behind a weak 4G signal or a router that trips with the mains. Ask what the device does in the meantime.
The right answer names a local buffer, a stated number of hours of stored readings and an automatic back-fill once the link returns. Ask also whether alarms still sound locally, through a hooter or a relay, without any cloud call.
Request a test. Pull the network cable during the demo and watch the timestamps afterwards.
Which machines and protocols can they actually read?
Name your own equipment. Give them the PLC make, the energy meter model, the weighing indicator and the old lathe with only a 4-20 mA output. A capable team asks for the manuals and the wiring diagram before quoting.
Ask which protocols they have commissioned before, such as Modbus RTU, Modbus TCP, OPC UA or MQTT, and which they would need to learn. Ask who touches a controller, because a careless write to a PLC register can stop a line.
Read-only access is the safer default for the first phase.
- Controller makes and firmware versions they have connected
- Read-only or read and write access to registers
- Sensors retrofitted on machines with no digital port
- Written sign-off from your maintenance head before any wiring
How will you know a reading is correct?
A dashboard that looks tidy can still be wrong. Ask how the team verifies each signal against the gauge on the machine, the manual log or a handheld meter. A good answer includes a parallel run of a few days before anyone relies on the numbers.
Ask about calibration dates, sensor scaling and the alert thresholds. Who sets them, and who approves a change? Ask how a bad reading, such as a flat line or a sudden spike, is flagged instead of plotted as if it were true.
The test is simple. Can they show you one alarm that fired for a real reason?
Who supports the sensors after commissioning?
Installation is a week. Sensors live for years. Ask who replaces a failed probe, who handles a gateway that stops reporting, who pushes security patches and how fast they respond when a night shift calls.
Find out whether support is a named person or a ticket queue, what hours it covers and what spare units sit on your site. Ask for the last three incidents on a comparable site and how each was closed.
Before you sign, write down five of these questions, send them to two teams and compare the replies side by side.
IoT partner question sheet
Six rows on a single sheet, one per question: ownership, data and code, offline behaviour, protocols, verification and after-sales support. Each row has columns for the vendor’s written answer, the proof offered, a red, amber or green mark and a name for who checked it. A scoring line sits at the bottom.
Open a blank worksheet to printQuestions owners ask
Should we own the devices or rent them?
Owning gives you control and a clean exit. Renting lowers the first outlay but ties you to the vendor’s billing. Ask what happens to the readings and the hardware if the subscription stops.
Do we need the source code?
If dashboards and rules are central to your plant, yes, or at least an escrow arrangement. Without it, a change of vendor means rebuilding from zero.
How long should a pilot run before we expand?
Long enough to cover a full production cycle, a shift change and one network outage. Compare every reading with your manual log before adding more machines.
Who should be in the room for vendor meetings?
Bring the maintenance head, the person who runs the line and whoever manages your network. They spot gaps that an owner reading a proposal will miss.