Safety Sensor CSS 180Product Information

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ApplicationThe CSS 180 non-contact, electronic safetysensor is designed for application in safetycircuits and is used for monitoring the positionof movable safety guards. In this applicationthe safety sensor monitors the closed positionof hinged, sliding or removable guards with theaid of a coded actuator.

The CSS 180 Safety Sensor fulfils the require-ments for proximity devices with definedbehaviour under fault conditions according toEN 60947-5-3 with the classification PDF-M(self-monitoring). Furthermore, the requirementsof Control Category 4 to EN 954-1 are alsosatisfied.

The standard IEC EN 61508, the latest specifi-cation for ensuring universal compliance tointernational safety standards, was used as a guideline for the development of the safetysensor. Consequently, the CSS 180 safety sen-sor can be used in SIL 3 applications to IEC61508.

Function, principle of operationThe CSS 180 Safety Sensor and CST 180actuator are a matched pair. As the actuatorapproaches the sensor, the sensor excites theactuator at a predetermined resonant frequencyand then reads back the actuator oscillation.The sensor evaluates the actuator frequencyand its distance to the actuator.

Identification of the actuator is interpreted as a closed guard by the safety sensor, and thesafety outputs are enabled.

The safety sensor is a dual channel design withtwo short-circuit proof, safe PNP outputs, eachof which can switch up to 500 mA. Due to con-tinuous internal function tests and the monitor-ing of the safety outputs, a number of CSS 180 Safety Sensors can be wired in se-ries without detriment to the control category.Series wired safety sensors continue to fulfilthe requirements of Control Category 4according to EN 954-1.

The Safety Sensor CSS 180and corresponding Actuator CST 180

Safety Sensor CSS 180

CSS180CSS 180• PDF-M / EN 60947-5-3• EN 954- 1 Control Category 4 • IEC 61508, suitable for use

in SIL 3 applications• BG Type-Certification

in preparation

The application, mounting and usageBoth the sensor and actuator are small andcompact. They can be fitted easily in any posi-tion on a machine guard or other object to bemonitored. The actuator has two sets of fixingholes for attachment parallel or square to themounting surface. The sensor can be attachedusing a mounting clamp (accessory) or with thetwo M18 nuts (supplied).

If required, both the actuator and the sensorcan be flush mounted using the M18 x 1mmstandard housing threads.

The sensor and actuator are encapsulated,vibration-proof and suitable for application in harsh, dusty or dirty environments. Theycomply to the requirements for the degree of protection IP 67.

Adjustment is simple. A large switching dis-tance and the possibility of also being able tooperate the sensor and actuator with an offsetenables large tolerances to be accommodatedon the safety guard.

The small hysteresis of 0.5 mm and a repeat-ability of 0.2 mm result in precise, repeatableswitching points throughout its operationallifetime.

The correct functioning of the sensor, a fault inthe sensor output, a crosswire short and finallyactuation of the sensor itself by the actuatorare signalled by the visual diagnostic 3 colourLED. The LED can also be used as an adjust-ment aid during fitting.

The electronic diagnostic output indicates anactuated sensor. If a sensor is operated nearthe limit of its switching distance, for exampledue to the sagging of a guard door, it is detect-ed even before the safety outputs are disabled,and results in an intermittent pulse on the elec-tronic diagnostic output and visual diagnosticLED.

In a similar way, faults which do not immediate-ly compromise the safe operation of the sen-sor, for example a crosswire short, are sig-nalled as an advance warning. The machinecan in this case be run down in a controlledmanner.

Misalignment in the safety guard can be easilycompensated

Key features of the Safety Sensor CSS 180:• Non-contact, no wear• Can be flush-mounted• Assured operating distance Sao 7 mm,

assured release distance Sar 9.5 mm• Accurate, repeatable switching points,

hysteresis 0.5 mm, repeatability 0.2 mm,can be actuated offset

• Monitored series wiring of the sensorsin Control Category 4 to EN 954-1.

• Max. length of the sensor chain 200 m(depending on output load and cablecross-section).

• 2 PNP safety outputs, 24 VDC, 500 mArating per output, short-circuit proof

• Visual diagnostics via LED.• Electronic diagnostic output 24 VDC,

50 mA.• Advance warning on approaching

hysteresis area.• Advance fault warning, enabling

controlled machine shut-down.• Control Category 4 to EN 954-1.

• Self-monitoring, PDF-M classification to EN 60947-5-3.

• Suitable for use in applications up toSIL 3 to IEC 61508, PFH value < 5,5 x 10-9

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Properties, mounting and use

4

Wiring in Series

200 m

Series wiring of the Safety Sensor CSS 180:A number of CSS 180 safety sensors can bewired together in series to form a chain. The re-dundant outputs of the first sensor are in thiscase wired to the inputs of the second sensor,and so on. The safety sensors in the chain areself-monitoring. The last sensor in the chainprovides the two short-circuit proof, PNP out-puts each rated at 500 mA for further connec-tion to the safety control circuit. The safetyrequirements according to EN 954-1, ControlCategory 4 remain fulfilled for the completechain. Faults within the chain, e.g. a cross-wireshort, are detected. This includes faults in thewiring to the safety control monitor, which arealso automatically detected.

To make cable routing and interconnection ofthe safety sensors as simple as possible, awide range of pre-wired options are available:

For large, extensive guard systems, the SafetySensor is available with separate input andoutput cables. The series wired safety sensorscan then be built up to a length of over twohundred metres by "daisy chaining" the de-vices. When the cables are routed in controlcable channels, the cables do not need to be shielded. The Y in the part number of theSafety Sensor CSS 180 identifies this version.

For compact systems, or where the controlcables are parallel routed to a centralisedcontrol cabinet, the input and output leads ofthe safety sensor are combined in one cable.The series wiring of a number of sensors in thiscase can be realised in the control cabinet orjunction box. This version is identified by an M inthe part number of the Safety Sensor CSS 180.

A single cable version is available for individualsensor monitoring and is also suitable for thefirst sensors in a series. The E in the partnumber of the Safety Sensor CSS 180identifies this version.

Note on the total length of a safety sensor chainThe voltage drop over a long sensor chainshould be taken into account when planningcable routing.

The exact value of the operating voltage, wirecross-section and cable length, its temperature,the number of sensors connected and theinput load of the safety control monitor are all factors that must be considered.

An approximately 200 m long sensor chainconsisting of six sensors has at 20°C, 100 mAinput current into the safety control monitorand 0.5 mm2 cable cross-section, a voltagedrop of approximately 1.5 V. If junction boxesare installed, a cable with 1.5 mm2 cross-section should be laid between the junctionboxes. When the cables are routed in controlcable channels, shielding is not necessary. The cables must however be routed separatelyfrom supply and power cables. Local sourcesof external interference must be properly sup-pressed.

The power supply for the CSS 180 safetysensors must provide protection againstpermanent overvoltage. Therefore, SELF orPELF mains supply units are reccomended.The maximum permissible fuse protection forthe sensor chain is 1.6 A gL/gG.

55

DiagnosticsVisual diagnostics is achieved using an LED inthe end cap of the safety sensor. The operatingstate is indicated using three different colours.Supply voltage, sensor actuation, operationnear critical limits (sensor operation near max.switching distance, too high an ambient tem-perature) and faults in external wiring are indi-cated. In this way maintenance is simplified.Misalignment, for example due to the saggingof a safety guard, is indicated before the safeenabling outputs switch off.

Diagnostics

6

Diagnostics

The diagnostic function of the Safety Sensor CSS 180The safety sensor indicates the operating stateand faults in three colours in the transparentend cap. The electronic diagnostic output signalsfaults before the safety outputs switch off andenables a controlled shut-down in emergency.

Function table of visual diagnostic LED, electronic diagnostic output and safety outputs

Sensor condition Diagnostic LED colour in Electronic diagnostic output Safety the sensor end cap 24 VDC, 50 mA outputs

No target/ Power on Green 0 V 0 VActuated Yellow 24 V 24 VActuated in the limit area Flashes yellow 2 Hz cycle 24 VFault Flashes red 3 s delay 1 min delay

24 V -> 0 V 24 V -> 0 V

Mode of operation: Safety outputsThe opening of a guard door disables the safeoutputs of the CSS 180 sensor immediately.

Faults, where the safe functioning of a safetysensor can no longer be assured, also lead tothe immediate disabling of the safe outputs. A fault that does not immediately effect thefunction of a safety sensor, for example due toa cross-wire short, does not result in an imme-diate disabling of the safe outputs. The dia-gnostic output switches to low and the safeoutputs remain enabled.

The production process is not stopped abrupt-ly and the machine can be set to a hold posi-tion. If the fault is still present after one minute,the safe outputs disable. After fault rectifica-tion, the sensor can be reset by opening andclosing the relevant guard door. The safe out-puts enable and allow a restart. This preventsunexpected (automatic) start up.

Visual diagnostic (red) Cause of fault1 pulse Fault on Output Y12 pulses Fault on Output Y23 pulses Cross-wire short Y1/Y24 pulses Ambient temperature too high5 pulses Incorrect or defective actuatorContinuous Internal fault

Mode of operation: Diagnostic LEDThe green LED signals that the sensor is readyfor operation. The supply voltage is presentand there are no faults. The sensor is notactuated.

When the CSS 180 sensor is actuated by theCST 180 target, the LED changes from greento yellow. The safety outputs switch to enable.

If the actuator is near the limit of the sensorswitching distance, the yellow LED flashes. Thesafe outputs remain enabled and the sensorcan be readjusted before the safety outputsstop the machine. Errors in the actuator codingor the sensor outputs are signalled by a redflashing LED. The safe outputs then switch offafter a delay of one minute. An internal fault isindicated by a continuous red LED and, if safeoperation is not ensured, results in an immedi-ate disabling of the safety outputs.

Mode of operation: Electronic diagnostic outputThe short-circuit proof electronic diagnosticoutput can be used for central monitoring orcontrol operations, for example in a PLC. Innormal operation, the diagnostic output is high(+ 24 VDC) when the door is closed, i.e. thesensor is actuated by the target.

If a sensor is operating near the limit of thesensor switching distance, for example due toa misaligned guard, the diagnostic outputsends a 2 Hz pulse sequence. The fault canthen be rectified before the target becomescompletely misaligned, i.e. outside the maxi-mum switching range, and disables the outputs.

A fault is not only indicated by the red LED,but also by the electronic diagnostic output,which switches to low after a 3 second delay.In combination with the safety outputs (which,unless safe operation is not ensured, disableafter a delay of 1 minute) it is therefore possibleto bring the production process to a stop in acontrolled manner.

Six different fault conditions are signalled bythe diagnostic LED flashing with predefinedpulse sequences or with continuous red light.

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Switching distances, flush mounting, dimensions

Flush mounting of the sensor CSS 180The CSS 180 sensor and the CST 180 actuatorcan be flush-mounted. Flush mounting how-ever reduces the switching distance. Theswitch point of the sensor is reduced byapprox. 1.5 – 2 mm when flush-mounted. Theexact reduction depends on the immediate en-vironment and must be determined in situ.When the sensor and actuator protrude 2 mmout of their mountings the switching distance isnot reduced.

Typical response range of the sensor CSS 180

SON

Switch-on point SON

< SH

< SOFF

SOFF

Switch-off point SH

= Hysteresis area

Sao

Assured operation pointS

ar Assured release pointaccording to EN 60947 –5-3

The envelope curves indicate the switch-onand switch-off points of the CSS 180 sensorrelative to the target. The maximum offset ofthe target from sensor axis is approx. 5 mm.Flush-mounting of the sensor or actuator re-duces the switching distance. Changes in tem-perature have only a slight effect on the switch-ing points.

Sw

itchi

ng d

ista

nce

S

Offset

Dimensions of the CSS 180 Safety Sensor.

Dimensions of the CST Actuator.

Refer to order information for cabletypes, cable length and cable cross-sectional area.

Wiring example

24 V

0 V

BNBU

WHBK

13 23

14 A2

E1 A1E2

24

N

L

BN BNBU BU

WHBK

WHBK

BN BNBU BU

WHBK

WHBK

BN BNBU BU

WHBK

WHBK

M

Series connection of CSS-8-180 Safety Sensors in large systemsThe sensors have separate input and outputcables. The output of one sensor can be di-rectly wired into the input of the next sensor.The sensor chain can be built up over a lengthof two hundred metres.

Sensors used: 1 Safety Sensor CSS-8-180-2P-E-L:This sensor has one output cable. It is de-signed for the beginning of a chain or for useas a single device.

3 Safety Sensors CSS-8-180-2P-Y-L:These sensors have separate input and outputcables. The output of the first sensor is wiredinto the input of the next sensor and so on.This type of sensor can also be used as thefirst sensor in a chain, if the supply voltage isbridged to the safety inputs.

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CSS-8-180-2P-Y-L

Input: grey cable

Operating voltage: (BN) brown P (+24 V)

(BU) blue 0 V

Safety input: (WH) white channel 1

(BK) black channel 2

output: black cable

Operating voltage: (BN) brown P (+24 V)

(BU) blue 0 V

Safety output: (WH) white channel 1

(BK) black channel 2

CSS-8-180-2P-E-L

Output: black cable

Operating voltage: (BN) brown P (+24V)

(BU) blue 0 V

Safety output: (WH) white channel 1

(BK) black channel 2

ActuatorCST 180-1

ActuatorCST 180-1

ActuatorCST 180-1

ActuatorCST 180-1

Safety ControlModule

Feedback

Sensor:CSS 8-180

-2P-E-L

Sensor:CSS 8-180

-2P-Y-L

Sensor:CSS 8-180

-2P-Y-L

Sensor:CSS 8-180

-2P-Y-L

This type of sensor can also be used as thefirst sensor in a chain, if the supply voltage isbridged to the safety inputs. For very long sen-sors chains it is recommended to feed thepower supply directly to the first sensor in thechain to avoid excessive voltage drop. The safeoutputs of the last sensor in the chain areconnected to the safety control module.

If junction boxes are used, standard installationcable can be used for the wiring betweenjunctions. When laid together with controlcables in a separate cable channel, shielding isnot necessary.

24 V

0 V

13 23

14A2

E1A1 E2

24

N

L

GY

BNBU

WHVT

BKWH

0 V

WHVT

0 V

GYBKRD

0 V

WHVT

0 V

24 V

0 V

BNBU

BNBU

BNBU

GY

BKRD

GY

BKRD

M

Series connection of Safety Sensors CSS 180 in small systems with a centralisedcontrol cabinet or wiring via junction boxes.

Wiring example

Sensors used: 1 Safety Sensor CSS-8-180-2P+D-E-L:This sensor has one output cable. It is de-signed for the beginning of a chain or for useas a single device.

3 Safety Sensors CSS-8-180-2P+D-M-L:The inputs and outputs of the sensors arebrought out in one cable. The sensors arewired together in series in the control cabinetor in junction boxes.

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CSS-8-180-2P+D-M-L

Operating voltage: (BN) brown P (+24 V)

(BU) blue 0 V

Safety input: (WH) white channel 1

(VT) violet channel 2

Safety output: (RD) red channel 1

(BK) black channel 2

(GY) grey diagnostic output

CSS-8-180-2P+D-E-L

Operating voltage: (BN) brown P (+24 V)

(BU) blue 0 V

Safety output: (WH) white channel 1

(BK) black channel 2

(GY) grey diagnostic output

ActuatorCST 180-1

ActuatorCST 180-1

ActuatorCST 180-1

ActuatorCST 180-1

Safety ControlModule

Feedback

Sensor:CSS 8-180

-2P-E-L

Sensor:CSS 8-180

-2P-Y-L

Sensor:CSS 8-180

-2P-Y-L

Sensor:CSS 8-180

-2P-Y-L

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Ordering information

Ordering informationSafety Sensors Cable VersionCSS- 8- 180- 2P -E -L 4-wire End or single device with pre-wired cableCSS- 8- 180- 2P -E -LST 4-wire End or single device, pre-wired cable with connectorCSS- 8- 180- 2P +D -E -L 5-wire End or single device with diagnostic output, pre-wired cableCSS- 8- 180- 2P +D -E -LST 5-wire End or single device, diagnostic output, pre-wired cable with connectorCSS- 8- 180- 2P -Y -L 2 x 4-wire Series device with double pre-wired cableCSS- 8- 180- 2P -Y -LST 2 x 4-wire Series device with double pre-wired cable with male / female connectorsCSS- 8- 180- 2P +D -M -L 1 x 7-wire Multifunction device with diagnostic output, pre-wired cableCSS- 8- 180- 2P +D -M -LST 1 x 7-wire Multifunction device with diagnostic, pre-wired cable with connector

Requirements for the Safety Control Module: Dual-channel safety inputs, suitable for PNP semiconductor outputs. The internalfunction tests of the sensor cause the outputs to sporadically switch off for a millisecond. This must be tolerated by the control module. The following safety control modules from the Schmersal programme are suitable for this application: AZR 200 TL, AZR 321 AR, SRB 308 IT, SRB 219 IT

Mounting clamp Magnetic latch

Safety Sensor Actuator Mounting clamp Magnetic latch

AccessoriesCSA- M-1 Magnetic latchH 18 Mounting clamp

Actuator CST-180- 1

Technical data: Safety Sensor CSS 180

Standards EN 60947-5-3, EN 954-1, IEC 61508Enclosure Glass-fibre reinforced thermoplasticProtection class IP 65, IP 67Mode of operation InductiveActuator CST 180-1Cable type, depending on version 4 x 0,5 mm2, 5 x 0,34 mm2 or 7 x 0,25 mm2

Connecting plug (optional), depending on version M12, 4-pole, 5-pole or 8-poleCable length: 2 m, with 2 connecting cables 2 m + 0,25 m Switching distances:

Nominal switching distance Sn 8.0 mmIndicated limit range Sn 7.0 mm – 8.5 mm

Assured operating distance to EN 60947-5-3 Sao = 7.0 mm, Sar = 9.5 mmHysteresis H ≤ 0.5 mmRepeatability ≤ 0.2 mm

Ambient conditions:Ambient temperature -25 ºC to +55 ºC (at +70 ºC Ie = 0.1A)Storage and transport temperature - 25 ºC to +85 ºCResistance to vibration 10-55 Hz, amplitude 1 mmResistance to shock 30 g / 11 msSwitching frequency f 3 Hz

Response time ≤ 30 msRisk time ≤ 30 msElectrical characteristics:

Rated operating voltage Ue 24 VDC -15% / +10%Rated operating current Ie 1.0 ANo load current I0 0.05 AResidual current Ir ≤ 0.5 mAProtection class IIOvervoltage category IIIContamination level 3Rated impulse withstand voltage Uimp 0.8 kVRated insulation voltage Ui 32 VAC/VDC

Safety outputs PNP, short-circuit proofOutput current Max. 0.5 A per outputVoltage drop on output DU Max. 0.5 VUtilisation category DC12 Ue/Ie 24 VDC / 0.5 A

DC13 Ue/Ie 24 VDC / 0.5 ASignalling output: PNP, short-circuit proof

Rated operating voltage Ue2 Max. 4V below UeRated operating current Ie2 Max. 0.05 AUtilisation category DC12 Ue/Ie 24 VDC / 0.05 A

DC13 Ue/Ie 24 VDC / 0.05 ASafety standards

According to EN 954-1 Control Category 4According to EN 60947-5-3 PDF-M According to IEC 61508 PFH value < 5,5 x 10-9

For the calculation of the PFH Value for a machine or system according to IEC 61508, the PFH value for individual sensors must be added together. This is independent of the method of sensor wiring.

BG approval: In preparation. The certification is based on six sensors in series.

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Technical data

K. A. Schmersal GmbHIndustrielle SicherheitsschaltsystemeMöddinghofe 30D-42279 WuppertalTel.: +49-(0)2 02 / 64 74-0Fax: +49-(0)2 02 / 64 74-100Internet: www.schmersal.comE-Mail: info@schmersal.com 5.0

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