Eaton Crouse-Hinds MTL5081 Millivolt/Thermocouple Isolator
ManufacturerEatonModelMTL5081Product TypeMillivolt / Thermocouple Isolator
01Technical Summary
The Eaton Crouse-Hinds series MTL5081 is a one-channel isolator for low-level DC millivolt signals originating in a hazardous area. It passes an isolated millivolt signal to a safe-area receiving instrument and is intended for thermocouple circuits that use external cold-junction compensation.
Selection ControlMatch the exact model, part number, installed system, wiring, approvals, and required revision before ordering.
02Applications
- Thermocouple signal isolation with external cold-junction compensation.
- Hazardous-area millivolt measurements connected to safe-area receiving equipment.
- Legacy MTL5000 installations requiring an exact MTL5081 replacement.
- Low-level sensor circuits where galvanic separation is required.
03Specifications
| Manufacturer | Eaton |
|---|---|
| Model | MTL5081 |
| Product Type | Millivolt / thermocouple isolator |
| Number of Channels | 1 |
| Signal Source | Any DC millivolt source |
| Input / Output Range | 0 to +/-50 mV; overrange to +/-55 mV |
| Output Resistance | 60 ohm nominal |
| Transfer Accuracy | <0.05% of reading or +/-5 uV, whichever is greater |
| Temperature Drift | +/-(2 uV + 0.002% of input) per deg C |
| Response Time | Typically within 10% of final value in 150 us |
| Frequency Response | DC to 4 kHz |
| Supply Voltage | 20...35 V DC |
| Maximum Current Requirement | 20 mA |
| Power Dissipation | 0.5 W at 24 V; 0.7 W at 35 V |
| Isolation | 250 V AC between safe, hazardous, and supply circuits |
| Power Indication | Green LED |
| Hazardous-Area Application | Zone 0, IIC, T4-T6 when suitably certified |
04Features
Design and Function
- Isolates low-level DC millivolt signals between hazardous and safe areas.
- Supports thermocouples when external cold-junction compensation is provided.
- Switch-selectable safety drive can be enabled or disabled.
- A second switch selects upscale or downscale drive on thermocouple burnout or cable breakage.
- Fast response supports changing low-level process signals.
- Separate safe, hazardous, and supply circuit isolation is documented.
- Front power indication supports basic local status checking.
Verified Identity
- Manufacturer: Eaton Model: MTL5081 Product Type: Millivolt / Thermocouple Isolator
05Compatibility
- Confirm that the field source is a millivolt or thermocouple signal within the documented range.
- External cold-junction compensation is required for thermocouple use.
- Match terminals 1 and 2 for the field input, 11 and 12 for output, and 13 and 14 for supply.
- Confirm the 20...35 V DC supply and the hazardous-area loop certification.
- Eaton identifies MTL5581 as the nearest current equivalent, but wiring, mounting, and loop approval must be reviewed before migration.
06Maintenance & Replacement
- Record the safety-drive enable and upscale/downscale switch settings before replacement.
- Verify input polarity and reproduce field, output, and supply wiring exactly.
- Test zero, span, burnout response, and isolation after installation.
- Do not interpret a shorted sensor cable as a guaranteed detected condition; the documented safety drive addresses burnout or open cable.
- Retain loop-approval and entity-parameter documentation with the maintenance record.
FAQFrequently Asked Questions
What signal does MTL5081 handle?
It handles a DC millivolt source over a 0 to +/-50 mV range, with overrange to +/-55 mV.
Can it be used with thermocouples?
Yes, when the thermocouple application uses external cold-junction compensation.
What happens on thermocouple burnout?
Switch settings can enable an upscale or downscale safety drive.
What supply voltage is required?
It requires a 20...35 V DC supply.
How many channels are provided?
MTL5081 is a one-channel isolator.
What replacement does Eaton list?
Eaton lists MTL5581 as the nearest equivalent, subject to wiring, mounting, and certification checks.
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