The Schmersal SRB301MC-24V is a high-performance safety relay module. Avantajele sale de bază includ 3 contacte de siguranță plus 1 semnal de ieșire, STOP 0 categoria de oprire, Nivel de performanță e (PL e) și acoperire de diagnostic ≥99%. It is widely deployed in safety protection systems for various industrial automation equipment. Featuring a dedicated design for magnetic safety switches and cross-wire detection function, it delivers outstanding performance in safety gate monitoring applications. Please check compatibility with safety input devices during model selection, and strictly follow wiring specifications during installation to ensure safe and reliable system operation.
- Codul modelului Explicația
The SRB301MC-24V is a safety relay module of the PROTECT SRB series manufactured by Schmersal, Germania. The breakdown of the model code is as follows:
| Segment de cod | Definiţie |
| SRB | Cod de serie: Safety Relay Block |
| 301 | Codul funcției: 3 safety contacts and 1 semnal de ieșire, compatible with single/dual-channel safety inputs |
| MC | Characteristic code: Designed for signals from BNS series magnetic safety switches, supports cross-wire detection |
| 24V | Rated operating voltage: 24V AC/DC, compatible with AC and DC power supply |
Order Numbers: 101190684 (Versiune standard), 161190684 (International Version), 151190684 (China Version)
- Specificatii tehnice principale
| Categorie | Date tehnice | Observații |
| General Specifications | ||
| Tip | Safety monitoring module, emergency stop safety relay | STOP 0 categoria de oprire |
| Tensiune de operare | 24V și (-15%/+10%) / 24În DC (-15%/+40%) | Maximum ripple voltage: 10% |
| Consumul de energie | 2W | Design cu consum redus de energie |
| Protecție la intrare | IP20 (Terminale) / IP40 (Locuințe) | Suitable for control cabinet installation |
| Caracteristici de intrare | ||
| Monitoring Channels | Switchable single/dual channel | Cross-wire detection supported |
| Tip de intrare | Passive contacts / Active signals (AOPDs) | Compatible with safety light curtains, butoane de oprire de urgență, etc. |
| Curent de intrare | >500mA | Reset time of monitoring circuit: aproximativ. 1 doilea |
| Caracteristici de ieșire | ||
| Contacte de siguranță | 3 contacte (2NC + 1NU) | DC13: 24V/6A; AC15: 230V/6A |
| Signal Output | 1 contact auxiliar | Pentru indicarea stării sau alarmă |
| Nivel de performanță | PL e (Highest level) | Conform cu EN ISO 13849-1 |
| Categoria de siguranță | Categorie 4 | Compliant with EN IEC 61508 |
| Diagnostic Coverage | ≥99% | Design de înaltă fiabilitate |
| Caracteristici fizice | ||
| Dimensiuni | 22.5mm × 100mm × 121mm | Montare pe șină DIN, economisind spațiu |
| Montare | 35mm șină DIN standard | Standard industrial mounting |
| Temperatura de operare | -25°C ~ 60°C | Gamă largă de temperatură pentru medii industriale |
| Terminale | Borne cu șuruburi | Cable cross-section: 0.25mm² ~ 2.5mm² |
| Certificari | BG, UL, CSA, CE | Conform standardelor internaționale de siguranță |
- Lista de compatibilitate între mărci
| Marca | Model de înlocuire | Descrierea compatibilităţii |
| Schmersal | SRB E 301MC-24V (103014374) | Enhanced replacement, fully compatible with improved performance |
| Siemens | 3SK1111-1AB30 | Equivalent safety relay, 3 contacte de siguranță, 24În DC |
| Schneider | XPSAC5121 | 24V AC/DC, 3 safety contacts and 1 semnal de ieșire |
| Omron | G9SA-321-T075 | 24În DC, 3 contacte de siguranță, STOP 0 categoria de oprire |
| ABB | MSR132TP | 24V AC/DC, 3 contacte de siguranță, single/dual channel |
Selection Guideline: Match voltage and contact quantity; do not downgrade safety performance level; keep identical mounting dimensions.
- Full Model List of SRB Series
| Model | Voltaj | Configurare contact | Funcții speciale | Număr de ordine |
| SRB301MC-24V | 24V AC/DC | 3 Siguranţă (2NC+1NO) + 1 Semnal | For magnetic switches, cross-wire detection | 101190684 |
| SRB301MC-24V-STSS | 24V AC/DC | 3 Siguranţă (2NC+1NO) + 1 Semnal | Protecție la scurtcircuit, for magnetic switches | 101190685 |
| SRB301-24V | 24V AC/DC | 3 Siguranţă (2NC+1NO) + 1 Semnal | General type, no optimization for magnetic switches | 101190686 |
| SRB302MC-24V | 24V AC/DC | 4 Siguranţă (3NC+1NO) + 1 Semnal | Dual-gate monitoring, for magnetic switches | 101190687 |
| SRB301MC-110V | 110V și | 3 Siguranţă (2NC+1NO) + 1 Semnal | For magnetic switches, high voltage version | 101190688 |
| SRB301MC-230V | 230V și | 3 Siguranţă (2NC+1NO) + 1 Semnal | For magnetic switches, high voltage version | 101190689 |
- Defecte comune & Depanare
| Fenomen de eroare | Cauze posibile | Soluții |
| Power indicator off | 1. Alimentare întreruptă sau tensiune anormală | 1. Check power connection and voltage (20.4V~28,8V) |
| 2. Internal fuse blown | 2. Replace 2A internal fuse | |
| Safety contacts fail to operate | 1. Semnal de intrare anormal | 1. Inspect safety input devices (Opri, light curtains, etc.) |
| 2. Incorrect cross-wire detection setting | 2. Adjust QS switch (Top: cross-wire protection off; Fund: cross-wire protection on) | |
| 3. Damaged contacts | 3. Replace the safety relay module | |
| No signal output | 1. Safety circuit not reset | 1. Check reset conditions (manual/automatic reset) |
| 2. Damaged signal output contacts | 2. Test continuity of signal contacts | |
| Deplasări false frecvente | 1. Electromagnetic interference | 1. Add shielding and keep away from interference sources |
| 2. Poor cable connection | 2. Recheck cable connections | |
| 3. Ambient temperature out of range | 3. Ensure temperature within -25°C ~ 60°C |
Check power first, then inputs; wrong settings are common causes; watch out for interference and reset requirements.
- Medii de aplicație & Cazuri industriale
6.1 Scenarii aplicabile
Machinery Safety Protection: Emergency stop systems for injection molding machines, punch presses, press brakes and other stamping equipment
Linii de producție de automatizare: Signal processing for safety light curtains to prevent personnel from entering hazardous areas
Logistică & Depozitare: Safety gate monitoring for stackers and conveyors with BNS magnetic safety switches
Mașini de ambalare: Safety interlock for filling and labeling machines to ensure operational safety
Producție de automobile: Safety zone monitoring for welding robots and coating lines
6.2 Scenarii nerecomandate
Harsh outdoor environments: IP20 protection rating is not suitable for outdoor installation
Highly corrosive environments: No anti-corrosion coating, incompatible with acid, alkali and corrosive media
Medii cu vibrații ridicate: Vibration over 5g may shorten relay service life
High temperature over 60°C: Will degrade performance and service life
6.3 Cazuri de aplicare
Caz 1: Stamping Production Line for Automotive Parts
Aplicație: Emergency stop system and signal processing of safety light curtains for 3 punch presses
Configurare: One SRB301MC-24V installed on each press, connected with emergency stop buttons and safety light curtains
Efect: Realizes instant STOP 0 shutdown with diagnostic coverage ≥99%, reducing safety risks
Caz 2: Safety System for Food Packaging Machinery
Aplicație: Safety gate monitoring for filling and capping machines with Schmersal BNS magnetic safety switches
Configurare: SRB301MC-24V monitors 2 safety gates; cross-wire detection prevents cable failures
Efect: Complies with food industry safety standards and improves equipment reliability
Caz 3: Stackers in Automated Warehouse
Aplicație: Safety gate monitoring and emergency stop system for stacker aisles
Configurare: SRB301MC-24V connected to magnetic safety switches and E-stop buttons; signal output linked to PLC
Efect: Stacker is locked when safety gates are open, upgrading warehouse safety level
Detailed Application Cases of Schmersal SRB301MC-24V Safety Relay
This model is optimized for magnetic safety switches, dual-channel monitoring and cross-wire detection, compliant with PL e / Categorie 4. It is widely used for safety gates, emergency stops and safety light curtains. Below are practical industry cases including wiring schemes, operation methods and application values.
- Machine Tool Industry (Main Application)
Caz 1: Poarta de siguranta & E-Stop Interlock for CNC Punch Press / Press Brake
- Dispozitive de potrivire: Schmersal BNS magnetic safety switches (machine protective gates) + Mushroom-head emergency stop buttons
- Operațiunea:
Adopt dual-channel input and cross-wire detection to monitor front and rear protective gates;
Safety contacts open immediately when gates are opened or E-stop is triggered, executing STOP 0 instant shutdown;
Auxiliary signal contacts connect to PLC for gate status and fault alarm upload.
- Valoare: Prevent personnel from accessing stamping hazardous areas; detect cable breakage and short circuit to avoid safety failure.
Caz 2: Rotating Hatch Monitoring for Machining Centers
- Dispozitive de potrivire: BNS magnetic safety switches (rotating protective gates)
- Operațiunea: Switchable single/dual channel; equipment cannot start if gates are not fully closed; power circuit cuts off immediately if gates are opened during operation.
- Echipamente aplicabile: Vertical machining centers, drilling & mașini de frezat, polizoare.
- Linii de producție de automatizare & Robotics
Caz 1: Safety Fence Monitoring for Robot Workcells
- Dispozitive de potrivire: Magnetic safety switches (fence access gates) + Safety light curtains
- Operațiunea:
Signals from safety gates and light curtains are wired in series to the relay;
Robot stops and locks when personnel intrude or gates are opened; on-site reset is required for restart.
- Scenarii tipice: Automotive component handling, welding robots, loading/unloading robot cells.
Caz 2: Centralized Emergency Stop Control for Production Lines
- Operațiunea: Emergency stop buttons at multiple workstations are connected in parallel to the module, cutting off power of motors and conveyors via unified safety circuit.
- Avantaje: Fast response and powerful circuit diagnosis, ideal for full-line safety interlock.
- Ambalare, Mâncare & Pharmaceutical Machinery
Caz 1: Guard Safety Protection for Automatic Filling & Sealing Machines
- Dispozitive de potrivire: BNS non-contact magnetic safety switches (movable machine guards)
- Operațiunea:
Frequent opening/closing of guards in food equipment leads to no mechanical wear for magnetic switches and longer service life;
Enable cross-wire detection to avoid safety hazards caused by aging and short-circuited cables in humid environments.
- Echipamente aplicabile: Beverage fillers, daily chemical packaging machines, pharmaceutical blister packaging machines.
Caz 2: Access Gate Interlock for Carton Packaging & Palletizing Machines
Magnetic switches are installed on equipment access gates. The palletizing mechanism and conveyors lock completely once gates are opened, protecting maintenance personnel.
- Logistică & Warehousing Equipment
Caz 1: Aisle Safety Gate Monitoring for Warehouse Stackers
- Monitoring Points: Protective gates and access gates of stacker travel aisles
- Logică: Stacker is disabled for travelling and lifting when gates are open; immediate shutdown and alarm during operation.
- Caracteristică: Cross-wire detection effectively diagnoses faults of long-distance cables in warehousing systems.
Caz 2: Zone Safety Protection for Belt / Roller Conveyors
Access gates on both sides of conveyors and line-mounted E-stop buttons are connected to the module, realizing full-section emergency stop. Widely used in express sorting and material conveying lines.
- Rubber, Plastic & Injection Molding Machinery
Caz: Poarta de siguranta & Mold Area Protection for Injection Molding Machines
- Dispozitive de potrivire: Magnetic safety switches (faţă & rear safety gates of injection machines)
- Operațiunea: Mold opening and part picking areas are high-risk zones. Mold closing action is locked when gates are opened to prevent pinching accidents. Complies with national safety standards for rubber & plastic machinery.
- General Auxiliary Applications (Small Equipment & Control Cabinets)
Caz: Small Automated Tooling & Test Equipment
For various custom assembly and test tooling, this relay builds cost-effective high-level safety circuits (Categorie 4 / PL e) with single E-stop and simple protective gates, suitable for small and medium-sized custom equipment.
Supplementary Operation Notes
- For optimal performance, use with Schmersal BNS magnetic safety switches (original manufacturer recommended combination).
- Enable cross-wire detection for long-distance wiring, humid or dusty sites.
- All above applications meet EN ISO 13849 PL e and Category 4, acceptable for equipment exported to the EU.
- Not recommended for outdoor, highly corrosive or severe vibration environments. IP40 rating is only for indoor control cabinet installation.
Contactor,întrerupător de circuit,invertor solar,contor electric,baterii solare















NH42-63-318x560.png)




