Schneider / Zelio smart relays and plug-in relays

On a Zelio Logic smart relay, deleting one letter from the part number changes the supply to 24 V AC and removes the analogue inputs. Changing another letter removes the clock and restricts you to ladder programming.

Zelio covers two different Schneider ranges: Zelio Logic programmable smart relays, and Zelio plug-in interface and power relays. Both are panel staples.

Zelio Logic smart relays

A real alternative to cabled logic or a small PLC, for systems up to 40 I/O.

Reading the part number

Take SR2B121BD, a compact smart relay with 12 I/O, 24 V DC, clock, display and 4 relay outputs.

Three ordering rules from Schneider's own catalogue

These are the ones that catch people, and Schneider states each of them directly.

1. Relay or transistor output is a single digit.

Schneider: replace the digit with 1 for relay output or 2 for transistor output. So SR2B121BD is relay and SR2B122BD is transistor.

Relay outputs switch AC and higher currents. Transistor outputs switch DC faster and last longer on high cycle work. They are not interchangeable and the difference is one character.

2. Deleting the D gives 24 V AC and loses the analogue inputs.

Schneider: to order a smart relay for a 24 V AC supply, delete the letter D from the end, giving references such as SR2E121B and SR2E201B. And the note in brackets is the important part: no analogue inputs.

So the AC version is not simply the DC version on a different supply. It has fewer capabilities. If the application uses an analogue input, it needs the DC version.

3. Removing the clock also removes a programming language.

Schneider: to order a smart relay without a clock, replace the letter E with the letter D, giving references such as SR2D201BD and SR2D201FU. And then: these units can only be programmed in LADDER language.

That is a much bigger difference than a missing clock. If your application is written in function block diagram, a no-clock unit cannot run it.

So check the existing part number carefully. One letter decides whether your program will load.

Only the 24 V DC modular base takes a communication module

A constraint worth knowing before specifying.

So if the application needs Modbus or Ethernet, the base has to be 24 V DC. A 240 V AC base cannot take a communication module at all.

Note also the limit is one of each. You cannot stack extension modules.

That constraint tends to decide the panel. Choosing a 24 V DC base for the communication module means the panel needs a 24 V supply, which then also feeds the interface relays and any DC field devices. See our Phaseo power supplies page for the ABL range.

Specifications

26 I/O in 125 mm of DIN rail is genuinely compact. That is the argument for a smart relay over a small PLC on a tight panel.

Zelio Soft 2

A replacement smart relay arrives blank. The program lives in Zelio Soft, and on a small machine that program is often the only documentation of how it works.

If you run Zelio Logic, back up the program files. They are small and easily lost.

Zelio plug-in relays

A separate range under the same brand: interface and power relays with sockets, Schneider class 8501.

The LED is a digit in the part number

Schneider's rule: catalogue numbers are shown for relays with LED. For relays without LED, replace the number 2 in the catalogue number with 1.

The LED is what tells a technician the relay is energised. On a panel that gets fault-found regularly, it is worth the small extra cost. And if you are replacing a relay that has one, match it, or the next person loses a diagnostic they were relying on.

Relay plus socket in one part number

A useful ordering shortcut.

Schneider: to order a relay complete with socket, add the suffix S. The example given is RSB2A080RD plus RSZE1S48M becomes RSB2A080RDS.

Note these are sold in lots of 20. So the combined part is for panel building rather than a single spare.

For one relay, order the relay and socket separately.

Two things that catch people on sockets

The relay and socket combination can derate. Schneider specifies that when mounting an RXM2 series relay on an RXZE2M socket, the thermal current must not exceed 10 A.

So the relay rating alone is not the answer. The pairing sets the limit.

And some sockets need terminals jumpered. Schneider notes that when using a relay with the RSZE1S48M socket, terminals must be jumpered.

That is a wiring step, not a fault. If a relay on that socket does not operate, check the jumpers before replacing anything.

Socket wiring layouts differ

Worth knowing when replacing a socket, because it changes the panel wiring.

Fitting the wrong layout means rewiring, not just replacing. Check which one is in the panel before ordering.

The separated layout is generally preferred where control and load circuits are at different voltages, because it keeps them physically apart on the socket.

Relay or smart relay?

Worth stating because customers ask.

A smart relay replaces a panel full of relays and timers. If a machine has six timers and a dozen relays doing sequencing, one SR2 does the same job in less rail space and can be changed without rewiring.

The trade-off is that the logic becomes invisible. A relay panel can be read from the drawing; a smart relay cannot. Keep the program backed up and the drawing marked up.

Before ordering a replacement

What to send us

The full part number. Every character matters on Zelio Logic, because output type, supply, clock and analogue capability are all single characters.

Whether you need the socket, and which layout.

Whether the relay has an LED.

For a smart relay, whether extension or communication modules are fitted.

Which programming language the application uses, since that constrains which variants will run it.

What we can supply

Current production. Zelio Logic SR2 and SR3 bases, I/O and communication extension modules, programming cables and Bluetooth interfaces. Zelio RXM, RSB, RPM, RUM and RPF relays with sockets, retaining clips and marker accessories. Quoted with a delivered lead time.

Bulk. Interface relays are a panel consumable. Send us the schedule and we will quote relays, sockets and accessories together.

Discontinued. Earlier Zelio and Telemecanique relays. Surplus where available.

Related

Schneider overview, Phaseo power supplies for the 24 V supply behind the panel, TeSys contactors and Modicon M340 and M580.

For interface relays from other brands see Phoenix Contact PLC-INTERFACE and Omron MY and G2R.

Send us your part numbers

On Zelio Logic, send the reference exactly. A missing letter is not a typo, it is a different supply voltage and a different feature set. 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 Schneider Electric. Schneider Electric, Zelio, Zelio Logic, Zelio Soft, Phaseo and Telemecanique are trademarks of Schneider Electric. All trademarks, brand names and catalogue numbers are the property of their respective owners and are used here for identification purposes only.