SiteIt's Saturday, 11pm. The case packer has stopped on a servo alarm. Your fitter is on their own and has never seen this one before. They ring a controls engineer they trust, who says, "Switch to video. Show me the drive."
Ten minutes later the fitter has found a parameter that was changed during the week and never saved. The machine runs. Nobody had to drive anywhere.
That's the good version. The other version is an hour on a shaky phone call, a fitter holding a camera in one hand and a meter in the other, and a line that's still stood at 1am.
A video call is a brilliant tool for some breakdowns and a slow way to fail at others. The trick is knowing which kind you've got in the first few minutes.
What a video call is good at
Remote help works best when the problem is information, and the person on site has the hands and the skills to act on it. In our experience that covers a lot of night shift faults:
- reading an alarm code or a fault history the fitter doesn't recognise
- finding a changed or lost drive parameter
- talking through the sequence to find which step the machine is stuck on
- spotting a sensor that's out of line, dirty or looking at the wrong target
- pointing out where a component is, when the fitter has the drawings but not the machine knowledge
Reading fault codes with someone who knows the drive is often quicker than the manual. Our post on reading drive fault codes covers what to look for first.
What it can't do
A camera can't feel a bearing that's running rough. It can't smell a winding that's cooked. It can't tell whether a chain has stretched or whether that gearbox noise is new.
Mechanical failures, worn parts and anything that needs a part swapped usually need hands on site. So do safety circuit faults. If the light curtain or the guard switch won't reset, someone needs to find out why it won't, and fix that properly. A remote voice telling a fitter how to get round it is the last thing you want. See our post on safety relays and light curtains for the safe way in.
The person holding the phone matters most
Here's the bit people forget. A video call doesn't move the skill to site. The person on site still does the work, and they need to be competent for it.
The Electricity at Work Regulations say nobody should do work that needs technical knowledge or experience to prevent danger, unless they have that knowledge or experience, or are under the right level of supervision (regulation 16). HSE's code of practice for PUWER says the same for maintenance in general: it should only be done by people competent to do it (L22, paragraph 79).
Can someone on a video call give that supervision? For reading a screen or changing a parameter the fitter already understands, often yes. For a fitter who has never been inside a drive cabinet, being talked through it on a phone is a different matter. We'd say no.
Watch for one request in particular. "Can you just put your meter across those two terminals?" With the cabinet live, that's live work. The regulations only allow it when it's unreasonable for the kit to be dead, reasonable to work on it live, and proper precautions are taken (regulation 14). The person on the call can't see the whole cabinet, the fitter's probes or how close their hand is to the busbar. If the job needs live testing, the fitter has to be competent to do it and has to make the call themselves. The voice on the phone doesn't get a vote.
Remote access to the PLC
Some suppliers and integrators can log in to your PLC or HMI over a remote link. That can save hours. It can also start a machine nobody expected to move.
Before you let anyone in, agree a few rules:
- someone on site is stood at the machine, with the area clear, for the whole session
- the remote engineer says what they're about to do before they do it
- nobody forces outputs or changes safety settings remotely
- a backup of the program is taken before any change, and again after
If you've never taken a backup, start this week. Our post on PLC program backups and version control explains how to keep them straight. And our guide to going online to a PLC to fault-find covers what to watch when anyone, local or remote, is online.
Set a time limit on the call
A video call that isn't working feels like progress. Every five minutes, someone says "nearly there".
We think the same rule applies here as to any breakdown. If it isn't diagnosed in 30 minutes, call for hands on site. Make the call to an engineer while the video call carries on, not after it's given up. The 30-minute rule post explains why waiting is so expensive. An engineer on the road at midnight is a lot better than one you start looking for at 2am.
Keep what you learned
The best thing about a video call is that it leaves a trail. Ask if you can screenshot the screens that mattered. Write down the parameter that was changed, the old value and the new one.
PUWER expects the information you give people to include "any conclusions to be drawn from experience in using the work equipment" (regulation 8). The code of practice says to record those conclusions, or make sure the right people know about them (L22, paragraph 114). Put the fix in the breakdown log against the machine, and tell the day shift. If the parameter changed once, someone changed it, and they may do it again.
What to do on Monday
- List three people you could video call on a night shift, and check they're happy to take the call.
- Write the rules for remote PLC access and stick them inside the panel door.
- Take a backup of the PLC and drive parameters on your five worst machines.
- Agree when a video call stops and an engineer gets called, and tell every shift.
* Paragraph numbers refer to L22, fourth edition (2014, amended 2018). Check HSE's PUWER code of practice for the latest.