The MSI-RM2B-01 safety relay, part number 547954, is a high-reliability module designed for the conversion of electronic safety outputs into potential-free relay contacts. It serves critical functions in safety systems, ensuring electrical isolation and enabling safe restart and feedback monitoring.
✅ Dual Safety Outputs: Two NO relay outputs (OSSD) for reliable circuit separation.
✅ EDM Integration: Feedback path support for External Device Monitoring (Y1/Y2).
✅ SIL 3 / PL e Certified: Meets highest safety levels (SIL 3, PL e, Category 4).
✅ Automatic Restart Functionality: No need for manual reset, reducing downtime.
✅ Wide Input Range: 24 VDC ±20% with tolerance for power fluctuations.
✅ High Mechanical Durability: 10 million cycles mechanical life.
✅ Compact & Durable: 17.5 mm wide PA66 housing with screw terminals.
✅ Status LEDs: Two green LEDs for output status indication.
✅ Overload Protected: Fuse protection at output and input levels.
✅ Simple Installation: Snap-on mounting and screw terminals for fast integration.
Series: MSI-RM2B
Application: Signal conversion of electronic safety outputs
Functions:
Feedback path for EDM (External Device Monitoring)
Automatic restart
SIL: 3 (IEC 61508)
SILCL: 3 (IEC/EN 62061)
Performance Level (PL): e (EN ISO 13849-1)
Category: Up to 4 (depends on upstream protection), EN ISO 13849-1
Mission Time (T<sub>M</sub>): 20 years
Mechanical life: 10,000,000 actuations
| Load Type | Current & Voltage | B10<sub>d</sub> (Cycles) |
|---|---|---|
| DC1 (Ohmic) | 2 A, 24 V | 10,000,000 |
| AC1 (Ohmic) | 0.5 A, 230 V | 1,300,000 |
| DC13 (Inductive) | 2 A, 24 V | 10,000,000 |
| AC15 (Inductive) | 0.5 A, 230 V | 1,300,000 |
| Low Load | – | 1,860,000 |
Supply Voltage (U<sub>B</sub>): 24 V DC ±20%
Max Power Consumption: 2.5 W
Safety Outputs: 2 OSSD relays (Normally Open, AC/DC type)
Signaling Output: 1 relay (non-delayed)
Max Continuous Current: 3 A per path
Fuse Protection:
5 A quick-acting
3.15 A time-delay
Input Line Resistance: Max. 50 Ω
Pickup Delay: 20 ms
Release Delay: 10 ms
Connections: 1 terminal block (screw type), 12-pin
Cable Cross-Section: 0.2 to 2.5 mm²
Mounting: Snap-on
Housing: PA66 plastic, gray color
Contact Material: AgNi10 + 5 mm Au
Weight: 120 g
Display Type: LED
No. of LEDs: 2 (Green)
LED 1 (K1): Relay 1 picked up
LED 2 (K2): Relay 2 picked up
Operating Temp.: 0°C to +50°C
Storage Temp.: -25°C to +70°C
Protection Class: IP20
Class: Protection Class II
Approvals: TÜV NRTL US, c UL US
| Pin | Function |
|---|---|
| 11 | Relay contact 1 OUT |
| 12 | Relay contact 1 IN, NC |
| 14 | Relay contact 1 IN, NO |
| 21 | Relay contact 2 OUT |
| 22 | Relay contact 2 IN, NC |
| 24 | Relay contact 2 IN, NO |
| A2 | 0 V |
| B1 | Sensor input channel 1 (24V) |
| B3 | Sensor input channel 2 (24V) |
| Y1/Y2 | EDM loop |
| n.c. | Not connected |
Customs Tariff No.: 85371098
ECLASS: 27371819 (Version 8.0 to 15.0)
ETIM: EC001449 (Version 5.0 to 10.0)
| Issue | Possible Cause | Recommended Action |
|---|---|---|
| ❌ No LED lights on the device | No power supply or incorrect wiring | Check 24 VDC supply and terminal connections |
| ⚠️ Only one green LED turns on | One relay is not activated | Check both sensor inputs and output load conditions |
| 🔄 Relay does not reset | Faulty automatic restart or blocked feedback loop | Verify EDM circuit wiring (Y1–Y2) and restart conditions |
| 🔌 Output not switching | Overload or fuse blown | Inspect output load, check 5 A/3.15 A fuse |
| 🔁 Repeated tripping | Excessive line resistance or intermittent fault | Ensure line resistance < 50Ω, check for wiring issues |
| 🌡 Overheating of housing | Exceeding current limits or ambient temperature | Reduce load, verify < 3 A per path, ensure ventilation |
| 🔄 Switching delay observed | Normal timing behavior | Observe pickup (20 ms) and release (10 ms) delays |
| Terminal | Description |
|---|---|
| 11 | Relay contact 1 OUT |
| 12 | Relay contact 1 IN, NC |
| 14 | Relay contact 1 IN, NO |
| 21 | Relay contact 2 OUT |
| 22 | Relay contact 2 IN, NC |
| 24 | Relay contact 2 IN, NO |
| B1/B3 | Sensor input channels (24V) |
| Y1/Y2 | External Device Monitoring loop |
| A2 | 0 V (Ground) |