The MTL5511 from the MTL5500 series interfaces one digital input from a switch or proximity detector located in a hazardous area. This device provides a 7-9Vdc sensor supply and delivers a relay contact output to safe-area circuits. The relay is rated for 35V, 2A, and 100VA for Zone 2 installations. Additionally, the unit includes green power, yellow status, and red line fault detection (LFD) LEDs. Its compact 15.8mm width saves panel space while delivering SIL2 and SIL3 safety integrity levels.
This isolator requires a 20-35Vdc power supply and consumes only 25mA at 24V. Typical power dissipation is 0.6W. The maximum safe input voltage is ±35V. Sensor supply voltage measures 7-9Vdc from a 1kΩ ±10% source, which complies with NAMUR standards.
The MTL5511 accepts digital inputs from mechanical switches, NAMUR proximity detectors, or other dry contact devices. Output characteristics follow clear thresholds: the relay opens when input current falls below 1.2mA (input circuit resistance above 10kΩ). The relay closes when input current exceeds 2.1mA (input circuit resistance below 2kΩ). Hysteresis is set at 200µA (650Ω) nominal, which prevents relay chatter near switching points. Response time is 10ms maximum.
The relay contact on the MTL5511 is designed for Zone 2 hazardous area locations. Contact rating is 35V, 2A, 100VA (resistive load). This relay provides a clean dry contact output that connects directly to PLCs, DCS systems, or other control devices. Unlike transistor outputs, the relay offers complete electrical isolation and handles a wider range of load types.
Line fault detection (LFD) is user-selectable via switches on the side of the unit. When enabled, the red LFD LED illuminates to indicate a broken wire or short circuit in the field wiring. This feature dramatically reduces troubleshooting time. The green LED confirms power is present, while the yellow LED shows the output relay state (energized or de-energized).
The MTL5511 carries SIL2 and SIL3 ratings according to IEC61508. Therefore, it is suitable for safety instrumented functions (SIF) up to SIL3 when used in appropriate architectures. This certification makes the device ideal for emergency shutdown systems, burner management, and other critical applications.
Galvanic isolation is rated at 250V rms between safe-area circuits and the power supply. The MTL5511 is approved for hazardous locations including Zone 0 input areas. It meets EN61326 EMC standards and carries IECEx/ATEX certification.
Operating temperature ranges from -20°C to 60°C. Storage temperature spans -40°C to 80°C. Humidity tolerance is 5-95% relative humidity, non-condensing. Dimensions are 109.8mm (L) x 118.8mm (H) x 15.8mm (W). Weight is only 150g.
Terminals accept stranded or solid conductors up to 2.5mm². Use crimp ferrules for secure connections. Mount the MTL5511 on a standard T-section 35mm DIN rail.
First, verify the power supply is within 20-35Vdc. Next, mount the unit on a 35mm DIN rail. Then, connect your switch or NAMUR proximity detector to the input terminals. The MTL5511 supplies 7-9Vdc to power the sensor. After that, wire the relay output (Zone 2 rated) to your safe-area control system. Finally, apply power and check that the green LED turns on. Use the side switches to enable or disable line fault detection per your application needs.
MTL5511 isolator (1 unit)
Pre-installed terminal blocks
Product identification label
Printed quick start guide
Note: Cables, sensors, and mounting accessories are sold separately. No certificates or warranty documents are included in the package.
1. What is the difference between MTL5511 and MTL5513?
The MTL5511 has one channel with a relay output (35V/2A). The MTL5513 has two channels with transistor-style outputs.
2. Can the MTL5511 be used in a SIL3 loop?
Yes. It is certified to SIL2 and SIL3 according to IEC61508, making it suitable for safety instrumented functions up to SIL3.
3. What does the red LFD LED indicate?
The red LED lights up when line fault detection is enabled and a wiring fault (open circuit or short circuit) is detected on the input side.
4. Is the relay output suitable for direct connection to a PLC input card?
Absolutely. The relay provides a dry contact rated at 35V, 2A, which works perfectly with most PLC digital input modules.
5. What is the maximum switching frequency of the relay?
The MTL5511 has a 10ms response time, so it handles switching frequencies up to approximately 50Hz. For higher speeds, consider the transistor-output MTL5513.
| Brand Name | MTL |
| Model No. | MTL5511 |
| Product Type | Isolator |
| hasMerchantReturnPolicy | Adjust according to reality |
| Shippingdetails | Adjust according to reality |
