Control system migration: from Simatic S5 to S7
Is your stacker crane or conveyor system still running on a Simatic S5, an S7-300/400 or an S7-mEC? Then your installation depends on a control system whose spare parts are running out. We replace that control system without you having to replace the installation.
A large share of the retrofits we have carried out came from exactly this: a control system that could no longer be maintained, while the mechanics had years of service left. We work from our own software framework for stacker cranes and conveyor systems, running on Siemens Simatic S7-1500F.
From Simatic S5 to S7-1500
Have you done this before?
Yes. A large share of the retrofits we have carried out came from exactly this: a control system that could no longer be maintained, while the installation itself was still perfectly sound.
This is not a side note to our work, it is the reason for it. Anyone calling us about an obsolete control system is calling about precisely what we have worked on most often.
Why does a Simatic S5 have to be replaced eventually?
Because Siemens took the S5 out of production decades ago. New parts are no longer made; what is still available comes from remaining stock and from dismantled installations.
As long as everything runs, you notice none of this. That changes on the day a central unit or an I/O card fails. You are then dependent on whatever can be found at that moment, at whatever price is asked for it.
My S5 has run for thirty years without trouble. Why act now?
That is precisely the argument that hides the risk. An S5 that runs for thirty years proves the installation was well built — not that spare parts exist.
The difference lies in who chooses the moment. Migrate while the installation is running and you plan the downtime yourself. Wait until something breaks and the moment is chosen for you, usually the worst possible one.
There is more to it: who can still work on it? The number of engineers who read STEP 5 and can get to the bottom of an S5 fault shrinks every year.
Is the existing program converted or rewritten?
Neither. We do not start from scratch, and we do not convert blindly either.
For stacker cranes and conveyor systems we have our own software framework that already contains the recurring functionality: positioning, motion profiles, load handling, transport routing, diagnostics and alarm handling. It runs on Siemens Simatic S7-1500F.
What remains is the part specific to your installation. That shortens the lead time considerably and it limits the risk: most of the software has already proven itself elsewhere.
There is another reason. An S5 program that has grown over thirty years contains ways of working that stem from the constraints of that time. Carrying those over one to one means taking those constraints into a control system that no longer has them. We work out what the installation has to do, and build that up with our framework.
Does the whole control cabinet have to be replaced?
Usually yes, and that is a deliberate choice — not additional work.
Time on site becomes shorter. A new cabinet is built and tested beforehand at our own workshop. What remains at your site is connecting and commissioning. Rebuilding the existing cabinet means all of that work happens on your premises, during the hours your installation is down.
The result is more reliable. Leaving obsolete components in an otherwise renewed installation means keeping the weakest link. The first fault then comes from exactly that part — on an installation that has just been handed over.
How much downtime does a migration cost?
That depends heavily on the scope of the migration, and the difference is large enough to make a decision about it beforehand.
Replacing only the control system is considerably faster: the existing cabinet and wiring stay in place, and the work on site is limited to swapping, connecting and testing.
Replacing control system and cabinet takes more time on site, because the field wiring is laid again as well. In return you are set for years, and we build and test the cabinet beforehand at our own workshop.
Which of the two makes sense for you depends on the condition of the existing installation. We assess that on site and set out both sides, including what each means for your downtime — so that you can make the trade-off yourself.
What does it deliver, apart from being supported again?
Diagnostics that tell you what is wrong instead of that something is wrong. Remote support, so that a fault is often resolved before anyone is on the road. Components that stay available for years. And documentation your own maintenance department can read.
Does this apply to S7-300 and S7-400 as well?
Yes, with a different urgency. This generation is still in full use at many companies, but is being phased out step by step: some components are already unavailable and the rest will follow.
It happens gradually, and that is exactly where the risk sits. With an S5, everyone knows it is over. With an S7-300 or S7-400 everything still looks normal — until the part you need happens to be gone.
If an extension or a rebuild is on your agenda anyway, this is the moment to take that step along with it.
Siemens S7-mEC that is no longer available
My installation runs on an S7-mEC. Why is that a problem?
Because the product is no longer supplied. If the unit fails, there is no equivalent replacement to order — you depend on whatever the second-hand market happens to offer that day.
With an embedded controller there is something on top of that. The control system does not run on a classic PLC but as software on hardware with a lifecycle of its own. If that hardware disappears, you lose not only the control system but the platform underneath it.
This controller was widely applied in warehouse systems at the time, including installations by Lalesse. If you have such a unit, this question will come up before long.
What can an S7-mEC be replaced with?
With a Simatic S7-1500 as a hardware PLC.
That is the platform we standardise on and the one our software framework for stacker cranes and conveyor systems runs on. Components stay available for years, and it is a control system for which engineers can be found anywhere — including if you ever want to continue with another party.
The step back from a software-based control system to a real PLC is deliberate. You get a control system that stands on its own, instead of software that depends on the lifecycle of the computer underneath it.
Will my operation and visualisation keep working?
Your higher-level system is left untouched; the operator panels are renewed.
The warehouse control system you work with stays the same. Your processes, your order flows and the way your people run the warehouse therefore do not change.
The HMI panels at the installation we do replace. They belong to the old control system and come along in the migration. Your operators get panels that respond faster and that, in the event of a fault, show what is wrong instead of only that something is wrong.
What happens to the existing I/O and field devices?
The control cabinet can usually stay in place for this migration. That is the big difference from an S5 migration.
An installation with an S7-mEC is considerably younger than one with an S5. The cabinet, the field wiring and the I/O are generally still sound. We replace the control system and the HMI panels; the rest stays as it is. That saves considerably on downtime and on cost.
We do advise going through the cabinet at that moment for components that have themselves been phased out. Whatever is already unavailable is best dealt with straight away: the cabinet is open anyway, and this is the cheapest opportunity you will get.
Is your installation still running on an obsolete control system?
Tell us which make you have, what year it was built and which control system is in it. We will tell you what is possible — including when the answer is “there is nothing you need to do here for now”.