Description
Technical Specifications
| Parameter Name | Parameter Value |
|---|---|
| Product Model | MTL3052 (MTL3052-RU-18-0-0 variants available) |
| Manufacturer | Eaton MTL (Measurement Technology Limited) |
| Product Type | Digital isolator, intrinsically safe interface unit |
| Series / Platform | MTL3000 Series interface units |
| Number of Channels | One, fully floating |
| Input Voltage | 4 to 12 V dc |
| Signal Bandwidth | DC to 10 kHz |
| Minimum Output Voltage | Vin minus (0.25 x current in mA) V |
| Input and Output Ripple | <1 mA peak-to-peak |
| Power Dissipation | 160 mW maximum at 12 V with 20 mA signal |
| Output Circuit Option A | Terminals 5 & 6: 15 V, 100 Ω, 150 mA, Um = 250 V rms or dc |
| Output Circuit Option B | Terminals 7 & 8: 15 V, 180 Ω, 83.3 mA, Um = 250 V rms or dc |
| FM Entity Parameters | Voc = 15 V, Isc = 83.3 mA, Ca = 0.75 µF, La = 5.2 mH |
| Location of Load | Zone 0, IIC, T4-6 hazardous area; Div 1, Group A hazardous location |
| Location of Unit | Safe area |
| Isolation | 250 V ac between input, output and power supply terminals; tested at 1500 V rms minimum |
| Replaceable Fuse | 50 mA, 5 x 20 mm glass to DIN 41571 sheet 2, semi-time-lag (M) |
| Earth Fault Protection | Optional, enabled by connecting terminal 8 to MTL4220 |
| Maximum Loop Impedance | 50 Ω with terminals 7 & 8; 130 Ω with terminals 5 & 6 |
| Transmission Distance | 0.5 km typical for IS applications (up to 3 km achievable with screened twisted pair) |
| Terminal Capacity | Conductors up to 4 mm² (12 AWG) |
| Mounting | 35 mm DIN top-hat rail to EN 50022, or flat surface |
| Ambient Temperature | -20 °C to +60 °C continuous; -40 °C to +80 °C storage |
| Humidity | 5 to 95% RH |
| Weight | 130 g |
| Lifecycle Status | Discontinued; MTL5500 Series is the recommended replacement |
Main Features and Advantages
Dual safety descriptions matched to the real loop: The MTL3052 gives the installer two output circuits rather than one compromise. The 15 V, 180 Ω output suits standard MTL800 data highways, while the 15 V, 100 Ω output absorbs the extra series resistance introduced when surge protection units are placed in the highway — a scenario that would otherwise push the loop beyond its permitted impedance and cause intermittent communication. Selecting the right pair of terminals at installation is the difference between a highway that runs reliably and one that fails only when a transient event occurs.
Certified for the most demanding classifications: With a Zone 0, IIC, T4-6 rating and FM approval for Division 1 Groups A through G under the entity concept, the MTL3052 can be applied in hydrogen and acetylene atmospheres where many interfaces are restricted to IIB. Entity parameters are explicitly published, so the design engineer can verify cable capacitance and inductance against the BASEEFA group values rather than relying on a generic statement of compliance. Optional connection of terminal 8 to an MTL4220 earth leakage detector adds “no-fail” earth fault protection, announcing a line-to-earth fault while the unit continues to work — particularly valuable on long data highways where a single ground fault would otherwise go unnoticed until it became a second fault.
Low energy, low heat, easy service: At only 160 mW dissipation, the MTL3052 places negligible thermal load on a densely packed marshalling cabinet, and its ripple of less than 1 mA peak-to-peak keeps the digital signal clean. The 50 mA semi-time-lag fuse is a standard 5 x 20 mm glass type that can be replaced in the field without returning the unit, and the 130 g housing clips onto a standard 35 mm top-hat rail alongside the rest of the MTL3000 family.
Application Field
The primary application of the MTL3052 is MTL800 Series multiplexer installations, where a single twisted-pair data highway carries both power and serial communication between a safe-area host and a distributed population of hazardous-area transmitters. One is installed in-line in the safe area for each highway, and a second unit serves the redundant highway in dual-highway configurations. Typical hosts are tank gauging systems, terminal automation systems and large tank farms where hundreds of field points must be gathered without running individual IS loops back to the control room.
Beyond multiplexers, the is used to return digital status from hazardous-area devices: mechanical limit switches on valve actuators, opto-transistor sensors on packaging and filling machines, and magnetic shaft encoders on rotating equipment located in classified areas, each through suitable current-limiting resistors. Because the unit passes DC to 10 kHz, it handles pulse trains and encoder outputs that a conventional 4-20 mA isolator cannot reproduce.
In brownfield plants, the is most often procured as a sustaining spare. MTL800 multiplexer networks in refineries, chemical terminals, pharmaceutical solvent stores and offshore facilities were installed decades ago and remain in service, and when an isolator fails the fastest recovery is a like-for-like unit with the same safety description and terminal configuration. The is also specified by system integrators building replacement cabinets for legacy multiplexer systems, where retaining the original IS interface avoids re-certifying the hazardous-area field wiring.
