MTL5081 takes a low-level dc signal from a voltage source in a hazardous area, isolates it and passes it to a receiving instrument located in the safe area. The module is intended for use with thermocouples utilizing external cold junction compensation. A switch located on top of the module enables or disables the safety drive in the event of thermocouple burnout or cable breakage; a second switch permits the selection of upscale or downscale drive as required.
Number of channels: One
Signal source: Any dc millivolt source
Location of millivolt source: Zone 0, IIC, T4–T6 hazardous area if suitably certified Div 1, Group A, hazardous location
Input and output signal range: 0 to ±50mV, overrange to ±55mV
Output resistance: 60Ω nominal
Transfer accuracy: Linearity and repeatability <0.05% of reading or ±5µV, whichever is the greater
Temperature drift: ±(2µV + 0.002% of input) per °C
Response time: Settles to within 10% of final value within typically 150µs
Frequency response: DC to 4kHz
Safety drive on THC burnout: Two switches on top of the module enable or disable the safety drive and select upscale or downscale drive
LED indicator - Green: provided for power indication
Power requirement, Vs: 20mA max, 20 to 35V dc
Maximum power dissipation within unit: 0.5W at 24V, 0.7W at 35V
Isolation: 250V ac between safe circuits, hazardous circuits and power supply circuits
Safety description - Terminals 1 and 2: Non-energy-storing apparatus (≤1.2V, ≤0.1A, ≤20µJ and ≤25mW). Can be connected without further certification into any IS loop with an open circuit voltage <28V.