SAFETY CONTROLLER SELECTION CRITERIA

Transcription

1 SAFETY CONTROLLER SELECTION CRITERIA It helps the selection process to view a safety controller as having four basic characteristics, each determined by the application requirements. This approach can be applied to any safety controller. FOUR BASIC SAFETY CONTROLLER CHARACTERISTICS Supply Requirements Select your supply voltage. While many voltages are possible (4VDC, 4VAC, 4VAC/DC, 5VAC and 30VAC), 4 VDC gives the most flexibility since virtually all controllers are available in this voltage. Also, since a transformer and rectifier are not required, this unit generally is less expensive and smaller than a 5VAC model. Regardless of supply voltage, it is always converted by the controller electronics to 4VDC for internal operation and for powering monitored input devices. Hence monitored devices only need to be rated for 4VDC. Requirements The first step is to determine whether you need single channel (up to control category designs used for safety functions up to PLd) or dual channel (control category 3 & 4 designs used for safety functions of PL d and PL e ) operation. Single-channel systems must monitor one NC positivebreak contact. Dual-channel systems can monitor NO/NC or contacts. Generally, these need to be isolated dry contacts since most controllers will view C-form contacts as a short circuit. Remember that 4VDC is supplied by the safety controller for monitoring these contacts. controllers are available for monitoring nonpotential free contacts (such as PNP outputs from light curtains). s are also available that allow users to field select the monitored contact configuration. Another consideration is crossed wire detection (a short between channels). This requires special circuitry in the safety controllers and is required for category 4 designs. monitor control relays and motor contactors with positive-guide contacts. Such feedback is required for safety control category 3 & 4 designs. A NC auxiliary contact is wired into the feedback loop (with or without a reset (start) button) to detect welded contacts in these external control devices. The safety controller detects the existence of a weld when the relay shuts down due to a power loss or open machine guard and prevents a restart. In order to reset the controller, the feedback loop must be closed (at least temporarily). If the NC auxiliary contact stays open due to a contact weld, the controller cannot be reset. Reset can be automatic or be manual. With automatic reset the controller will automatically reset (outputs close) when the machine guard is closed. A reset or start button can be added to the feedback loop if desired. The controller only needs to momentarily see a 4VDC signal at the feedback terminals to reset. With a manual monitored/trailing edge reset, some type of manual pushbutton is required. The feedback loop circuitry is designed so that it needs to see a 4V to 0V transition (trailing edge) in order to reset. This method of reset is generally required when a person can actually get inside a machine guard (where they would be at risk if the equipment should automatically restart when the guard closes). Output Requirements Determine the number and type of safety controller outputs required for machine control elements and signaling. Following are the types of safety controller outputs: A. NO safety enable circuits instant or timed. B. NO or NC auxiliary relay contacts not to be used Feedback & Reset Circuit Requirements for safety functions, but only for annunciation controllers with feedback capability can also C. Semiconductor outputs for annunciation. 3

2 INPUT OUTPUT No. of Independent Dual Channel Devices Output Type Outputs (Delayed) Auxiliary Output Dry Contact (Semiconductor) NO/NC (Isolated) NO/NC (C-Form) 6 4VDC 4VAC/DC 4-30VAC/DC Delayed (0) 0 () AES 35 (0) 0 (0) AES 35 3 (0) (0) SRB 30 MC SRB 30 MA SRB 30 ST SRB 30 LC(I) SRB 30 LC/B 5 (0) (3) SRB 504 ST () 0 () SRB ST 3 () (3) SRB 34 ST 0 (3) (0) SRB 03 MC (0) 0 () AES 35 3 (0) 0 () AES VAC 3 (0) (0) 4VAC/DC (0) 0 (6) 48-30VAC (0) 0 (6) 4VDC 4VAC/DC 4-30VAC/DC SRB 30 ST-30 SRB 30 SQ SRB 06 ST SRB 06 SQ SRB 06 ST-30 SRB 06 SQ-30 (0) 0 () AES 35 (0) 0 (0) AES 35 3 (0) 0 () AES (0) (0) SRB 30 AN Delayed () 0 () SRB AN 4VDC 6 (0) 0 () AES 35 3 (0) 0 () AES 335 (0) 0 (0) AES 65 (0) 0 () AES 65 4VDC (0) (6) SRB 07 AN-4VDC AES VAC (0) (6) SRB 07 AN-30 4VAC/DC (0) 0 (0) AES 0-4VAC(DC) 0VAC (0) 0 (0) AES 0. 4VAC/DC (0) 0 (0) AES -4VAC(DC) 0VAC (0) 0 (0) AES. NC 4VAC/DC 4 (0) (0) SRB 40 LC Isolated : Galvanically separated contacts C-Form : having a common contact between them 4

3 Control Category (Performance Level) E-Stop Switch 4 d Magnetic INPUT DEVICE TYPE AOPD 5 Pulse Echo Compatible Method of Reset 6 Cross Short AES 35 3 (d) Automatic AES 35 3 (d) Leading Edge SRB 30 MC 4 (e) Leading Edge Dipswitch Selectable SRB 30 MA 4 (e) Trailing Edge Dipswitch Selectable SRB 30 ST 4 (e) Trailing Edge Dipswitch Selectable SRB 30 LC(I) 4 (e) Leading Edge Hardwire Selectable SRB 30 LC/B 3 (d)/4 (e) 3 Leading Edge SRB 504 ST 4 (e) Trailing Edge Hardwire Selectable SRB ST 4 (e) Trailing Edge Dipswitch Selectable SRB 34 ST 4 (e) Trailing Edge Hardwire Selectable SRB 03 MC 3 (d) Leading Edge Dipswitch Selectable AES 35 3 (d) Automatic AES (d) Leading Edge SRB 30 ST-30 4 (e) Trailing Edge SRB 30 SQ 4 (e) Trailing Edge SRB 06 ST 3 (d) Trailing Edge SRB 06 SQ 3 (d) Trailing Edge SRB 06 ST-30 3 (d) Trailing Edge SRB 06 SQ-30 3 (d) Trailing Edge AES 35 3 (d) Automatic AES 35 3 (d) Leading Edge AES (e) Trailing Edge SRB 30 AN 4 (e) Trailing Edge SRB AN 4 (e) Leading Edge Dipswitch Selectable AES 35 3 (d) Automatic AES (d) Leading Edge AES 65 3 (d) Automatic AES 65 3 (d) Leading Edge SRB 07 AN-4VDC 3 (d) Trailing Edge AES 85 3 (d) Trailing Edge SRB 07 AN-30 3 (d) Trailing Edge AES 0-4VAC(DC) (c) Automatic AES 0. (c) Automatic AES -4VAC(DC) (c) Automatic AES. (c) Automatic SRB 40 LC 3 (d) Leading Edge 3 SRB 30LC/B: Performance Level e (Control Category 4) when used with a PL e device which features self-monitoring 4 5 AOPD: Active Optical Protective Device, e.g. safety light curtain 6 Automatic: outputs close as when inputs are satisfied Leading Edge: outputs close when inputs are satisfied and reset circuit is closed Trailing Edge: outputs close when inputs are satisfied and reset circuit is closed and reopened 5

4 Expansion Modules A majority of standard safety controllers used in the industry today will monitor discrete device with channels. Depending on the safety level to be obtained, wiring multiple switches in series to one safety controller can be a solution to scenarios such as an expanding application. This form of daisy-chaining however will not allow for individual diagnostics for low level safety device (i.e., limit switches) and can increase installation time and costs. expanders allow multiple devices to be wired to one safety controller while still having the ability of individual diagnostics. Multiple PROTECT input expanders can be used to wire a maximum of 80 dual channel devices. No. of Channel Devices Type of Output Configuration Configuration Terminal Connection E-Stop Switch d Magnetic AOPD Pulse Echo Compatible Module Indicator 3 (PNP Out) Expander 4 Dry NO/NC PROTECT-IE- PROTECT-PE- PROTECT-IE--SK PROTECT-PE--SK PROTECT-IE-0 PROTECT-IE-0-SK NO/NC NO/NC PROTECT-PE--AN PROTECT-PE--AN-SK Dry/Non- Floating PROTECT-PE-0 PROTECT-PE-0-SK AOPD: Active Optical Protective Device, e.g. safety light curtain 3 Module Indication: +4VDC PNP auxiliary signal indicating that all inputs are satisfied on the expansion unit S S S S SRB 6

5 Output Expansion Modules Output expanders allow a safety controller to increase the number of safe signals that can be delivered. Each SRB-EM module will provide an additional 4 dry contact safety outputs, dry contact auxiliary contacts and a connection to the main monitoring safety controller to complete an external feedback monitoring loop for the safety function. Additional Outputs Additional Auxiliary Outputs Terminal Connection Output Expanders 4 4VAC/DC 5VAC SRB 40 EM SRB 40 EM Dual Zone The SRB 0C and SRB 400C safety controllers allow for dual zone monitoring without adding the complexity of using a safety PLC. No software or programming tool is required for zone setup. is reserved for a global shutdown (the release of all safety outputs) such as an E-Stop actuation. is reserved for dropping out only half of the safety outputs of the relay. (More information can be found on Page 9.) Outputs Auxiliary Outputs Reset Cross Short Control Category (Performance Level) E-Stop Switch d Magnetic AOPD 3 Pulse Echo Compatible NO/NC Trailing Edge No SRB0CA 4 (e) Yes SRB0CA/Q 4 (e) No SRB0CA/T 4 (e) Yes SRB0CA/QT 4 (e) SRB0CS 4 (e) No Trailing Edge SRB0CS/T 4 (e) 4 0 NO/NC Trailing Edge No SRB400CA 4 (e) Yes SRB400CA/Q 4 (e) No SRB400CA/T 4 (e) Yes SRB400CA/QT 4 (e) SRB400CS 4 (e) No Trailing Edge SRB400CS/T 4 (e) Cross short monitoring and trailing edge not available for device. 3 AOPD: Active Optical Protective Device, e.g. safety light curtain 7

6 Safe Speed Speeds Standstill Safe Speeds Method Timer PNP Impulse PNP Impulse s 400VAC Back EMF 690VAC Back EMF Encoders/Resolver PNP Impulse s Control Category (Performance Level) Outputs 4VDC AZS 305-4VDC 4 (d) 3 0VAC AZS 305-0VAC 4 (d) 3 30VAC AZS VAC 4 (d) 3 4VDC FWS 06 3 (d) 4-30VAC/DC 4VDC 4-30VAC/DC FWS 06 3 (d) FWS (d) 4 FWS 05 3 (d) DNDS 4 (e) Selectable FWS 05 3 (d) FWS (d) 4 4VDC(VAC) AZR 3 S-4VDC(AC) 4 (e) 3 0VAC AZR 3 S-0VAC 4 (e) 3 30VAC AZR 3 S-30VAC 4 (e) 3 5VAC SSW 30 HV-5VAC 4 (e) 3 30VAC SSW 30 HV-30VAC 4 (e) 3 4VDC DNDS 4 (e) Selectable Mats/ -Hand Controls 4VAC/DC 48-30VAC Type of Reset E-Stop Switch Mat Two-Hand Control Rest SRB 30HC/R-4 Auto Rest SRB 30HC/T-4 SRB 0 ZH Rest SRB 30HC/R-30 Auto Rest SRB 30HC/T-30 mats operating with an electrical cross-short principle to detect actuation. Edges Monitors 4VDC Maximum Number of Edges Control Category (Performance Level) Method of Reset SE-400C 4 (e) Trailing Edge SE-00C (c) 4VAC/DC 4 SE-304C 3 (d) Trailing Edge 8