Schneider / OsiSense sensors and limit switches

Changing one letter from A to B turns a normally open sensor into a normally closed one. Changing L to P changes the cable material. And the last digit is the cable length in metres.

OsiSense is the Schneider sensor range, now also sold under the Telemecanique Sensors brand. Inductive and photoelectric sensors, limit switches and pressure switches.

Reading an OsiSense XS part number

Take XS612B1PAL2. Schneider describes it as an inductive sensor, XS6, M12, 53 mm long, brass, Sn 4 mm, 12 to 48 V DC, 2 m cable.

Three ordering rules that look like typos

Straight from the Schneider catalogue, and these are the ones that make a parts list look wrong when it is right.

1. A is normally open, B is normally closed

Schneider: to order a normally closed version, change the A to B.

One letter, and the sensor does the opposite. If a machine is behaving inversely after a sensor change, this is the first thing to check.

2. The last digit is the cable length

Schneider: XS508B1DAL2 becomes XS508B1DAL5 with a 5 metre cable.

So a 2 becomes a 5 and you have three more metres of cable. Useful when the existing sensor is short and someone has added a junction box. Order the longer version instead.

3. L is PvR cable, P is PUR

Schneider: for a PUR cable, replace the letter L by P.

And the two rules combine: XS518B1DAP2TF becomes XS518B1DAP5TF for a 5 metre PUR cable.

PUR matters more than it sounds. It stands up to oils, cutting fluids and constant flexing far better than PvR. On a machine with a moving cable or a coolant environment, the PUR version is what lasts.

If a sensor cable keeps failing rather than the sensor, that is the change to make.

Connector or cable

Compare these two:

M12 at the end means a connector rather than a flying lead. The connector version needs a mating cordset, which is a separate part.

On a machine that gets stripped down regularly, connectorised sensors save a lot of time. On a fixed installation, a cabled sensor is one less connection to fail.

The rated sensing distance assumes mild steel

The most important technical point about inductive sensors, and the cause of a lot of intermittent detection.

Sn, the rated sensing distance, is quoted for a standard mild steel target. Detecting anything else means applying a correction coefficient.

A sensor rated 8 mm on steel will detect aluminium at considerably less. If a sensor works on the bench and not on the machine, the target material is usually why.

The Fe/NFe models solve this

Worth knowing because it is a specific product rather than a workaround.

Schneider makes fixed sensing distance models for ferrous and non-ferrous materials, which detect different objects at a fixed distance irrespective of the type of material.

So on a line handling mixed materials, an Fe/NFe sensor gives the same sensing distance for all of them. No correction coefficient, no guessing.

That is the right answer for a machine that runs steel one week and aluminium the next, and it is a different part number rather than a setting.

Repeat accuracy

For all OsiSense XS sensors the repeat accuracy is 3 percent.

Schneider also notes the published sensing curves are representative typical curves, given as a guide to the approximate usable sensing distance. They are not a guarantee for a specific application.

Design in margin. A sensor set at the limit of its range will work until the temperature changes or the target shifts a millimetre.

Sensing ranges by body size

Across the range Schneider publishes bands of Sn 1 to 5 mm, 1 to 10 mm, 2 to 15 mm and 5 to 40 mm depending on body size and whether the sensor is flush or non-flush mountable.

Flush and non-flush are different sensors. A flush sensor can be embedded in metal; a non-flush one needs clear space around the face but reaches further. Fitting a non-flush sensor into a flush mounting will cause false detection from the surrounding metal.

Two-wire sensors need a minimum voltage

A wiring constraint that produces baffling faults.

Schneider specifies for certain sensors: ensure a minimum of 5 V between the positive and the sensor output at terminal 3. On others the figure is 10 V.

A two-wire sensor drops voltage across itself even when conducting. If the PLC input impedance is wrong, or several devices are in series, the sensor may not have enough voltage across it to operate properly.

The symptom is a sensor that reads intermittently or never quite switches, with nothing visibly wrong. A three-wire PNP sensor avoids the problem entirely, which is why most new installations use them.

Output and supply types

Compare XS612B1PAL2 and XS612B1MAL2. Same body, same 4 mm sensing distance, and one is 12 to 48 V DC PNP while the other is 24 to 240 V AC or DC.

One letter, completely different electrical behaviour. Fitting a DC sensor onto a 240 V AC circuit destroys it.

PNP and NPN

The same sink and source distinction that runs through every brand on this site. PNP switches the positive to the input; NPN switches the negative.

Fit the wrong one and nothing reads. In New Zealand and Europe PNP is the norm; NPN is more common on Japanese-built machinery.

Self-teaching thresholds

On certain models Schneider notes that thresholds of minus 20 percent, minus 11 percent and minus 6 percent can be obtained by pressing the self-teaching button.

So the sensitivity is set on the sensor, not just by mounting position. A replacement arrives at default, and if the original was taught to a specific threshold that setting needs repeating.

Connector pinouts

Body materials

In a New Zealand food or dairy plant, stainless is what survives. A brass-bodied sensor in a caustic washdown area will not last, and the failure looks like a sensor fault rather than a specification error.

The OsiSense families

XS series numbers run XS1 through XS8, covering different body styles, sizes and construction.

OsiSense and Telemecanique Sensors

Worth knowing when searching. OsiSense sensors are now also sold under the Telemecanique Sensors brand, with the same part numbers.

So a part listed as Telemecanique Sensors XS612B1PAL2 and one listed as Schneider OsiSense XS612B1PAL2 are the same sensor.

What to send us

The full reference. Every letter matters: output type, NO or NC, cable material and length.

Whether it is cabled or connectorised, and whether you need a cordset.

The target material, if you are specifying rather than replacing.

The environment. Washdown, coolant or oil changes both the body material and the cable type.

Whether the sensor was taught to a threshold.

What we can supply

Current production. The OsiSense XS, XT, XU, XCK, XCS and XML ranges, plus cordsets, mounting brackets and accessories. Quoted with a delivered lead time.

Bulk. Sensors are a consumable on any machine. Send us the schedule.

Discontinued. Earlier Telemecanique sensors. Surplus where available.

Related

Schneider overview. Preventa safety, which uses XCS safety interlock switches.

For sensors from other brands see Omron E3Z and E2E, Pilz PSEN and ABB Eden.

Send us your references

Send the reference exactly as written. An A where you expected a B is a normally closed sensor, not a typing error. Quotes in NZD including GST.

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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, OsiSense and Telemecanique Sensors are trademarks of Schneider Electric. All trademarks, brand names and references are the property of their respective owners and are used here for identification purposes only.