SICK / Flexi Soft safety controllers

The configuration lives in the system plug, not the CPU. Move the plug across and a replacement controller runs the existing safety program without a laptop.

Flexi Soft is the SICK modular safety controller. FX3 main modules with I/O, gateway, relay and motion extensions, on machines across New Zealand.

The system plug carries the configuration

The most important thing about replacing any Flexi Soft component.

SICK describes the main module as processing logic on the basis of the configuration stored in the system plug. The plug is a separate memory device that saves the safety controller's configuration.

Three consequences

A failed CPU is a straightforward swap. Fit the new module, move the system plug across, and the machine runs the same safety program. No software, no laptop, no revalidation of a changed configuration.

A CPU without a plug will not run. If you are buying a used main module, ask whether a plug is included, and expect that it usually is not.

Do not discard the plug from a failed controller. It is the part that matters and it is rarely the part that fails.

Confirmed part: SICK order number 1043700 is a system plug for the FX3-CPU0 and FX3-CPU1.

Same principle as the Jokab IDFIX on our ABB Jokab page, and the opposite of every controller that arrives blank.

A CPU on its own is not a system

Worth knowing before ordering.

SICK's stated minimum construction is a main module plus at least one extension module: an FX3-CPU0 with an FX3-XTDI, or an FX3-CPU1 with an FX3-XTIO.

The main module has no safety I/O of its own. It processes logic; the extension modules carry the inputs and outputs.

So a Flexi Soft system is a minimum of three parts: main module, system plug and at least one I/O extension.

The main modules

All carry an RS-232 port on an M8 female connector for configuration and real-time diagnostics, run on 24 V DC and are IP20.

The full order code form appears as FX3-CPU000000 for the CPU0.

The EFI interfaces are the reason to choose a CPU1

SICK is explicit that the FX3-CPU1 has the same functions as the CPU0 plus two EFI interfaces.

EFI, the Enhanced Function Interface, is a two-wire communication link between a SICK safety sensor and the controller. It carries far more than a switched output.

That last one is genuinely useful. A light curtain or scanner on EFI can be configured from the Flexi Soft rather than by connecting to the device itself, which on a ceiling-mounted scanner saves a ladder.

So if your installation uses EFI, a CPU0 is not a substitute for a CPU1. The interfaces are not an add-on module.

Maximum EFI cable length is 3 m, and the cable must be shielded.

The extension modules

The FX0-STIO is not a safety module

Worth stating plainly, because it sits in the same rail and looks like the others.

The FX0-STIO provides 6 non-safe inputs and outputs. On the FX3-XTIO, the test outputs XY1 and XY2 can also be used as further non-safe outputs.

Non-safe means exactly that. Those signals are for status indication, lamps and handshaking with a standard PLC. They cannot form part of a safety function.

If someone has used an STIO output in a safety chain, that is a finding rather than a fault.

A motion module costs you two slots

A specific and easily missed constraint. SICK states: each FX3-MOC0 module connected reduces the possible number of other extension modules by two.

So a Drive Monitor is effectively three slots, not one. On a system already near its extension limit, adding safe drive monitoring may mean it no longer fits.

Worth checking before quoting a motion module into an existing installation.

Gateways, and the limit of two

Flexi Soft connects to a standard PLC through a gateway, and up to two gateways can be integrated.

The gateway carries diagnostics and status to the standard control system. It does not carry the safety function.

So a failed gateway blinds the PLC to what the safety system is doing without compromising safety itself. The machine still stops correctly; the HMI stops telling you why.

The gateway is selected by network, and they are not interchangeable. Send us the network the plant runs.

Power comes two ways

A wiring detail that causes confusion on commissioning.

So a module can be powered up and communicating while its outputs have no supply. If an XTIO shows healthy on the bus and nothing switches, check A1 and A2 at that module.

FLEXBUS+ is the internal bus providing both the data interface and the logic supply as modules clip together.

The software is free

A genuine differentiator against other configurable safety platforms.

Flexi Soft Designer is licence-free. SICK provides it for programming, commissioning and continuous diagnostics.

Compare that with the configurable safety controllers on our Pilz PNOZmulti and Schneider Preventa pages, where the tool is a licensed purchase.

So the barrier to supporting a Flexi Soft system in-house is low. If a site has one and nobody can open the configuration, that is solvable by downloading the software rather than buying it.

Function blocks

The muting block is why Flexi Soft is on so many palletisers. Muting logic in a safety relay needs dedicated hardware; here it is a function block.

Flexi Loop and Flexi Line

Flexi Loop is the input-saving one. Safety switches chain in series on a single connection rather than consuming two inputs each, the same idea as the Jokab dynamic signal concept.

Flexi Line links controllers, so a long line with several Flexi Soft stations can share safety state without a gateway.

Both need supporting hardware. Tell us if the installation uses either.

What to send us

Which module failed. Main module, extension, gateway or relay module.

The full type code and the 7-digit order number.

Whether you have the system plug. If you do, a main module on its own is the order.

Whether the installation uses EFI, since that decides CPU0 against CPU1.

The network, if you need a gateway.

How many extension modules are fitted, if you are adding one.

Important: safety replacements

Flexi Soft components form part of a machine's certified safety function.

A like-for-like module with the original system plug preserves the configuration and the assessment. A different module type, or a reconfigured plug, does not.

We will supply exactly what you specify. If you ask for an alternative we will say what we believe is equivalent and what differs, but the decision belongs with whoever is responsible for the machine's safety. We are a parts supplier, not your safety engineer.

What we can supply

Current production. FX3 main modules, system plugs, XTIO, XTDI, XTDS and STIO extensions, all gateway variants, UE410 relay modules, Drive Monitor modules and encoder connection boxes. Quoted with a delivered lead time.

System plugs separately. The part that is usually missing from a used main module.

Discontinued. Earlier Flexi Classic and legacy SICK safety controllers. Surplus and tested used.

A note on spares holding

Because the configuration lives in the plug, a single spare main module covers every Flexi Soft station on a site.

Whichever controller fails, the spare goes in and that station's own plug goes with it. One module on the shelf, however many systems you run.

Add one spare of whichever extension module you have most of, and a Flexi Soft installation is well covered for very little.

We buy SICK Flexi Soft

Flexi Soft modules hold value. Keep system plugs with their controllers where you can, though a plug from a decommissioned machine has no value to anyone else and a bare main module does. See Sell To Us.

Related

SICK overview, safety light curtains, encoders and photoelectric sensors.

For safety controllers from other brands see Pilz PNOZmulti, ABB Pluto, Schneider Preventa and Allen-Bradley Guardmaster.

Send us your part numbers

Tell us whether you have the system plug. With it, a replacement main module is a swap rather than a commissioning job. Quotes in NZD including GST.

Request a quote

Industech is an independent supplier of new, surplus and used industrial automation equipment. We are not an authorised distributor of, approved by, sanctioned by, or affiliated with SICK AG. SICK, Flexi Soft, Flexi Loop, Flexi Line and EFI are trademarks of SICK AG. All trademarks, brand names and part numbers are the property of their respective owners and are used here for identification purposes only. Information on this page is for identification and does not constitute a safety assessment.