Series Connection PSEN

Transcription

1 Product Type: Name: Manufacturer: PSEN PSENcode, PNOZsigma Pilz GmbH & Co. KG, Safe Automation Document Release Number: 02 Release Date: 8 May 2012 Application Note - No _EN_02

2 Document Revision History Release Date Changes Chapter Creation all Correction Exclusion of liability We have taken great care in compiling our application note. It contains information about our company and our products. All statements are made in accordance with the current status of technology and to the best of our know-ledge and belief. However, we cannot accept liability for the accuracy and entirety of the information provided, except in the case of gross negligence. In particular it should be noted that statements do not have the legal quality of assurances or assured properties. We are grateful for any feedback on the contents. May 2012 All rights to this publication are reserved by Pilz GmbH & Co. KG. We reserve the right to amend specifications without prior notice. Copies may be made for the user s internal purposes. The names of products, goods and technologies used in this manual are trademarks of the respective companies. Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 2/25

3 Support Technical help round the clock! Technical support is available from Pilz round the clock. This service is provided free of charge beyond standard business hours. Americas Brazil Mexico USA (toll free) PILZUSA ( ) Asia China Japan Korea Australia Australia You can reach our international hotline on: Europe Austria Belgium, Luxembourg England France Germany Ireland Italy Scandinavia Spain Switzerland The Netherlands Turkey or mailto:support@pilz.com Pilz GmbH & Co. KG Safe Automation Felix-Wankel-Straße Ostfildern, Germany Telephone: Telefax: pilz.gmbh@pilz.de Internet: Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 3/25

4 Contents 1. Useful documentation Documentation from Pilz GmbH & Co. KG Documentation from other sources of information Hardware configuration Pilz products Hardware configuration Application Task Description Monitoring safety gate Series connection PSEN Maximum number of sensors in series Calculation of off-delay time Safety assessment Functional safety Safety-related characteristics in accordance with EN ISO Safety-related characteristics in accordance with EN Circuit diagram of the application Circuit diagram 1/ Circuit diagram 2/ Special features of series connection using PSEN Parallel connection of the solenoids of PSENsgate Increasing of the input voltage for increase the maximum cable length Table of figures Abbreviations PSEN Pilz Sensor PNOZ Pilz E-STOP Positive-guided (DE: Pilz NOT-AUS-Zwangsgeführt) OSSD Output Signal Switching Device Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 4/25

5 1. Useful documentation Reading the documentation listed below is necessary for understanding this application note. The availability of the indicated tools and safe handling are also presupposed with the user Documentation from Pilz GmbH & Co. KG No. Description Item No. 1 Pilz international homepage, download section 2 Operating instructions PSEN cs1.1p FR-xx 3 Operating instructions PNOZ s FR-xx 4 Operating instructions PSEN sg1c FR-xx 5 Data sheet PSEN Y junction EN 6 Data sheet PSEN T junction EN 1.2. Documentation from other sources of information No. Description Item No. 1 2 Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 5/25

6 2. Hardware configuration 2.1. Pilz products No. Description Order number Version Number 1 PSEN cs1.1p PNOZ s PSEN Y junction PSEN T junction Hardware configuration Fig. 1: Hardware configuration Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 6/25

7 3. Application Task 3.1. Description The following example shows the combination of PSENcode as a series connection. In a production line, there are three machine units combined in series with a conveyor belt. The safety gates of the units will be monitored by a PSENcode (S1, S2, S3) respectively and they are evaluated by a PNOZ s4 (A1). At opening of one of the units, the drive (M1) of the conveyor belt is cut off Fig. 2: Application safety gate series connection The process is divided into the following functions: Monitoring Safety Gate 1 Monitoring Safety Gate 2 Monitoring Safety Gate 3 Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 7/25

8 Monitoring safety gate The PNOZ s4 (A1) monitors the function of the series connected safety switches PSEN cs1.1p (S1, S2, S3). If at least one of the safety gates is open, the safety contacts from A1 do open, contactors KM1 and KM2 de-energise and the motor (M1) is cut off. Reset The safety relay PNOZ s4 (A1) can be started if the reset button S4 was closed and then released again (monitored reset) and if following conditions are fulfilled. safety gate 1 is closed and safety gate 2 is closed and safety gate 3 is closed and the actuator of safety gate switch S1 is within the response range of S1 and the actuator of safety gate switch S2 is within the response range of S2 and the actuator of safety gate switch S3 is within the response range of S3 and contactors KM1 and KM2 are de-energised. Feedback loop monitoring function The positive-guided N/C contacts of contactors KM1 and KM2 are monitored by the feedback loop S12-S34 of the safety relay (A1). Settings The terminator on the PNOZ s4 must be connected. The operating mode selector switch (mode) on the safety relay PNOZ s4 must be set to "Monitored reset, falling edge without detection of shorts across contacts (In2+)". Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 8/25

9 Series connection PSEN For safety series connection, sensors are needed with the ability for series connection. All safety switches PSENini, PSENcode, PSENslock and PSENsgate with two safety inputs can be used. The sensors can be connected directly to an approved evaluation device. The connected sensors act all on the same cut off path. By the safe inputs, the OSSD outputs and the thereby involved self-monitoring of the series connectable PSEN, the masking of errors resulting from the series connection can be excluded. The detection of an error occurs directly in the sensor. The sensor cuts off it s outputs immediately and disables the enable signal for the next sensors and the evaluation device. In order to simplify the wiring of the sensors, for the series circuit the cable separator PSEN Y junction and to evaluate the diagnostic connector PSEN T junction are available. INFO The sensors PSENcode (S1-S3) are approved in accordance with IP67. When using the cable separator PSEN Y junction and suitable connecting cables, the entire sensor part of the series connection will be classified as IP67. In the following some characteristics about handling the PSEN series connection are explained in more detail. Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 9/25

10 Maximum number of sensors in series Limitation of the maximum number of sensors in series is defined by three values: The PFHd-value of the safety functions. The maximum acceptable value for off-delay time. The voltage drop of the supply voltage over the input lead. PFHd The PFHd-value of each element in the safety function is added to a total PFHd-value (PFHd total ). Fig. 3: Calculation PFHd PFHd total = PFHd S3 + PFHd S2 + PFHd S1 + PFHd A1 + PFHd Actuator This value (PFHd total ) must not exceed the permissible range of each required safety level (PL/SIL), because the safety classification otherwise falls on a smaller level. Ascending of the first sensor (S1) each individual safety function can be calculated and the number of sensors until the PFHd limit value of the selected safety level can be determined. The detailed description of the calculations for the functional safety is shown in chapter 3.2. Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 10/25

11 Off-delay time The off-delay time of the components is a part of the entire admissible turn off time of a safety function (from the actuation of the sensing function till the termination of the hazardous machine function). The admissible turn off time is defined by the machine manufacturer according to the requirements of the machine (risk assessment etc.). The turn-off time is made up from the off-delay time of the complete sensor evaluation and the rundown-time of the machine. Fig. 4: Off-delay time Maximum admissible off-delay time = admissible turn off time rundown-time of the machine The maximum off-delay time is dividing out in the off-delay times of each individual device and sensors of the serial connection. The maximum number of sensors can be determined as one the off-delay times of the actuator, the evaluation device and the sensors sums until the maximum off-delay time computed before is reached. The detailed description of the calculations for the off-delay time is shown in chapter Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 11/25

12 Voltage drop of supply voltage over the input lead For considering the fall of voltage, several factors are important: The power supply device for the sensors must be able to provide the necessary power to supply the connected devices. Length, diameter and material of the used connection conductor. General Technical Data for the calculation of the example Condition: Power supply 24V/4A, Connecting cable 0.25mm 2, Sensor cable 0.25mm 2 From Technical Data PSEN cs2.1p: U B: 24V, Power consumption at U B: 2W, Tolerable voltage tolerance -20%/+20% From Technical Data PSEN Y junction: Current rating 2A at 40 C General calculations Current consumption at PSEN (I Sen ) = 2W / 24V = A ~ 84mA The current rating of PSEN Y junction is noted with 2A. Therefore, the entire available current (I avail ) will limit to this value. Max. voltage drop (U fall_max ) up to the sensor = Tolerable negative voltage tolerance at PSEN = 20% (24V) = 24V * 0.2 = 4.8V INFO To increase the maximum cable length, the input voltage can also permanently be increased till the positive voltage tolerance (An example of increasing the input voltage is shown in chapter 4.2). This will not be used in this example. Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 12/25

13 Guidelines for calculating the voltage drop on various cable types: Cable type PSS SB BUSCABLE LC 0.1V Sensorkabel 0.25 mm² 0.15V Sensorkabel 0.34 mm² 0.11V Sensorkabel 0.5 mm² 0.07V Voltage drop per 10 m (Cable up-and-down included) and per 100mA Calculation of voltage drop at conductor Length of the sensor lines L1 and L2 is assumed as 5m each. Length of the sensor line L3 is assumed as 20m. Length of the connection line L4 is assumed as 10m. Length of the connection line L5 is assumed as 50m. Fig. 5: Calculation of voltage drop The current in the conductor L1 - L3 is the same as the current of the sensors S1 S3. It is therefore 84mA each line. L3 Factor for the voltage drop = 0.15V (per 10m and 100mA) Factor of the cable length (L3) = 2 = 20m / 10m Factor from the current = 0.84 = 84mA / 100mA Voltage drop over the conductor resistance (U L3 ) = Factor from the current * Factor of the cable length * Factor voltage drop U L3 = 0.84 * 2 * 0.15V = 0.252V ~ 0.26V L1 L2 Factor for the voltage drop = 0.15V Factor of the cable length (L1/L2) = 0.5 = 5m / 10m Factor from the current = 0.84 = 84mA / 100mA U L1/L2 = 0.84 * 0.5 * 0.15V = 0.063V ~ 0.07V Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 13/25

14 L4 The summation of the currents I L3 and I L2 results in current of line L4 = 168mA. Factor for the voltage drop = 0.15V Factor of the cable length (L4) = 1 = 10m / 10m Factor from the current = 1.68 = 168mA / 100mA U L4 = 1.68 * 1 * 0.15V = 0,252V ~ 0.26V L5 The summation of the currents I L4 and I L1 results in current of line L5 = 252mA. Factor for the voltage drop = 0.15V Factor of the cable length (L5) = 5 = 50m / 10m Factor from the current = 2.52 = 252mA / 100mA U L5 = 2.52 * 5 * 0.15V = 1.89V ~ 1.89V I L5 < I avail Entire voltage drop The summation of the voltage for the highest total voltage drop (U fall_total ) applies to the farthest connected sensor (S3). U fall_total = U L3 + U L4 + U L5 = 2.41V U fall_total < U fall_max Result: The voltage drop in the example (2.41V) is smaller than the maximum admissible voltage drop up to the sensor of 4.8V. Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 14/25

15 Calculation of off-delay time In series connection of multiple devices, the off-delay time is added by the number of intermediary safety switches. Fig. 6: Off-delay times on series connection The calculation values can be taken from the respective Pilz operating manuals. The calculation values (t O_Actuator ) of the motor contactors (Actuator) can be taken from the technical data of the respective manufacturer. In the following examples maximum values are used for the calculation of off-delay time. Example: Actuation S3 Sensor Off-delay time (max) Activator Selection Inputs Actuator of time PSENcode (S3) 20ms 260ms Actuator 260ms 260ms PSENcode (S2) 20ms 260ms Input 20ms 280ms PSENcode (S1) 20ms 260ms Input 20ms 300ms PNOZ s4 (A1) 20ms - Input 20ms 320ms Entire off-delay time (max) at actuation of sensor S3 = 320ms + t O_Actuator Example: Actuation S2 Sensor Off-delay time (max) Activator Selection Inputs Actuator of time PSENcode (S3) 20ms 260ms PSENcode (S2) 20ms 260ms Actuator 260ms 260ms PSENcode (S1) 20ms 260ms Input 20ms 280ms PNOZ s4 (A1) 20ms - Input 20ms 300ms Entire off-delay time (max) at actuation of sensor S2 = 300ms + t O_Actuator. Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 15/25 Time accumulated Time accumulated

16 Safety assessment The circuit of PNOZ s4 (A1) is redundant with built-in self-monitoring. The safety function A1 remains effective in the case of a component failure. The correct opening and closing of the safety function relays of A1 is tested automatically in each on-off cycle. The PNOZ s4 has an electronic fuse. With a monitored reset, short circuits in the reset circuit on A1 are detected. Shorts are detected by the OSSD outputs from each PSENcode (S1, S2, S3). The safety relay PNOZ s4 (A1) and contactors KM1 and KM2 must be installed in a single mounting area (control cabinet) in order to exclude a short across the output. The safety relay A1 should be installed in a control cabinet with a protection type of at least IP54. The terminator on the PNOZ s4 must be connected. The distance between two transponder systems PSENcode (S1, S2, S3) must be at least 40 cm. Caution When connecting several units in series, the off-delay time increases in direct proportion to the number of interconnected safety switches. Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 16/25

17 3.2. Functional safety Safety-related characteristics in accordance with EN ISO No. Safety function Achieved 1 Machine shut down when a safety gate (S3) is opened. 2 Machine shut down when a safety gate (S2) is opened. 3 Machine shut down when a safety gate (S1) is opened. Prerequisites: Performance Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 17/25 Level Safety-related parts of the control system PL e Sensor (PSEN cs 1.1p S3) Sensor (PSEN cs 1.1p S2) Sensor (PSEN cs 1.1p S1) Logic (PNOZ s4 A1) Actuator (contactors KM1, KM2) PL e Sensor (PSEN cs 1.1p S2) Sensor (PSEN cs 1.1p S1) Logic (PNOZ s4 A1) Actuator (contactors KM1, KM2) PL e Sensor (PSEN cs 1.1p S1) Logic (PNOZ s4 A1) No. Description Identification Actuator (contactors KM1, KM2) 1 Common cause failure (CCF): Requirements are considered to be met 2 Mission time: 20 years 3 Operating interval (electromechanical components): Actuator KM1/2 4 Characteristic data of contactors KM1/KM2: B10d 2,000,000 (must be tested on implementation) 3 operations per hour Please note the further requirements of EN ISO , e.g. requirements for avoiding systematic faults.

18 Safety-related characteristics in accordance with EN No. Safety-related control function (SRCF): Achieved Safety 1 Machine shut down when a safety gate (S3) is opened. 2 Machine shut down when a safety gate (S2) is opened. 3 Machine shut down when a safety gate (S1) is opened. Integrity Level Subsystems SIL 3 Sensor (PSEN cs 1.1p S3) Sensor (PSEN cs 1.1p S2) Sensor (PSEN cs 1.1p S1) Logic (PNOZ s4 A1) Actuator (contactors KM1, KM2) SIL 3 Sensor (PSEN cs 1.1p S2) Sensor (PSEN cs 1.1p S1) Logic (PNOZ s4 A1) Actuator (contactors KM1, KM2) SIL 3 Sensor (PSEN cs 1.1p S1) Logic (PNOZ s4 A1) Prerequisites: No. Description Identification Actuator (contactors KM1, KM2) 1 Common cause failure (CCF): ß = 2 % (must be tested on implementation) 2 Proof test interval: 20 years 3 Operating interval (electromechanical components): Actuator KM1/2 5 Characteristic data of contactors KM1/KM2: B10d 2,000,000 Dangerous failure 3 operations per hour Please note the further requirements of EN 62061, e.g. requirements for systematic safety integrity. Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 18/25 rate 65 %

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21 4. Special features of series connection using PSEN In this chapter some characteristics of the series connection of PSEN are considered in detail and generally and independently of the previous example Parallel connection of the solenoids of PSENsgate Please note that in the series connection of the safety switches the maximum solenoid current and the permitted switching capability of the evaluation device. If necessary, the solenoids must be operated individually. Calculation of the maximum solenoid current of two parallel connected PSEN sg1c On a parallel connection, all partial currents are added to a total current (I mag_total ). Fig. 7: Calculation of max. solenoid current I mag_total = I mags1 + I mags2 Extract from technical details of PSEN sg1c Max. magnet current t <150 ms = 1,5A I mag_total = 1.5A + 1.5A = 3.0A The total current of the solenoids from two PSEN sg1c sums up to = 3.0A Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 21/25

22 Example 1: Controlled by a dual-pole semiconductor output PSSu E F DI OZ 2 Extract from technical details of PSSu E F DI OZ 2: Typ. output current at 1 signal and rated voltage of semiconductor output 2.0A The permitted switching capability of an dual-pole output from a PSSu E F DI OZ 2 amounts = 2.0A Total current > permitted switching capability Result: The total current in the example exceeds the permitted dual-pole output switching capability. The solenoid must not be controlled together, but there have to be used separate outputs according to the permitted switching capacity. Example 2: Controlled by PNOZ m1p relay outputs Extract from technical details of PNOZ m1p: Relay outputs Utilisation category in accordance with EN Safety contacts: DC13 at 24 V (6 cycles/min) 3.0A, 72W The permitted switching capability of PMOZ m1p relay output in accordance with the utilisation category (Control of DC electromagnetics) amounts =3.0A Total current = permitted switching capability Result: The total current in the example relate to the permitted switching capability of the relay output. The solenoids can be controlled together. Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 22/25

23 4.2. Increasing of the input voltage for increase the maximum cable length To increase the maximum cable length, the input voltage can permanently be increased by the voltage tolerance. This will be illustrated in the following example. Example: 9 PSEN cs1.1p to be connected in series This must depend on the expected number of sensors and cable lengths of the supply line, the voltage drop of each line are calculated. Used cable: 0,25mm 2 x 20m. Fig. 8: Comparison of different input voltages Case 1: U B : 24V (blue) The sensors are supplied with U B : 24V. The voltage drop across the line is too large. After only two sensors, the tolerance lower limit of the following sensors is exceeded. Case 2: Increasing the input voltage - U B : 24V (green) To increase the maximum cable length, the input voltage U B can be increased to a value which allows the first sensor (PSEN 1) to operate on the upper tolerance limit. The increased supply voltage is outcome of: Tolerance upper limit sensor + voltage drop over the line L1 (U Fall_L1 ) to sensor 1 Fig. 9: Increasing the input voltage Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 23/25

24 5. Table of figures Fig. 1: Hardware configuration... 6 Fig. 2: Application safety gate series connection... 7 Fig. 3: Calculation PFHd Fig. 4: Off-delay time Fig. 5: Calculation of voltage drop Fig. 6: Off-delay times on series connection Fig. 7: Calculation of max. solenoid current Fig. 8: Comparison of different input voltages Fig. 9: Increasing the input voltage Recommended printer settings Adobe Acrobat Reader ( ) PDF-XChange Viewer ( ) Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, Ostfildern, Germany 24/25

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