The MTL5573 converts a low-level dc signal from a temperature sensor mounted in a hazardous area into a 4/20mA current for driving a safearea load. Software selectable features include linearisation, ranging, monitoring, testing and tagging for all thermocouple types and 2-, 3- or 4-wire RTDs. (For thermocouple applications the HAZ-CJC plug on terminals 1–3 includes an integral CJC sensor). Configuration is carried out using a personal computer.

　　SPECIFICATION

　　See also common specification

　　Number of channels

　　One

　　Location of signal source

　　Zone 0, IIC, Hazardous area

　　Division 1, Groups A-D, hazardous location

　　Signal source

　　RTD excitation current

　　200µA nominal

　　Cold junction compensation, THC input Selectable ON or OFF

　　Cold junction compensation error

　　≤ 1.0°C

　　Common mode rejection

　　120dB for 240V at 50Hz or 60Hz

　　Series mode rejection

　　40dB for 50Hz or 60Hz Calibration accuracy (at 20°C)

　　(includes hysteresis, non-linearity and repeatability) Inputs:

　　mV/THC: ± 15µV or ± 0.05% of input value (whichever is greater)

　　Pt 100 - RTD: ± 80mΩ

　　Output: ± 11µA

　　Temperature drift (typical)

　　Inputs:

　　mV/THC: ± 0.003% of input value/°C

　　Pt 100 - RTD: ± 7mΩ/°C

　　Output: ± 0.6µA/°C

　　Example of calibration accuracy and temperature drift (RTD input)

　　Span: 250Ω

　　Accuracy: ± (0.08/250 + 11/16000) x 100% = 0.1% of span

　　Temperature drift: ± (0.007/250 x 16000 + 0.6) µA/°C = ±1.0µA/°C

　　Safety drive on sensor failure

　　Upscale, downscale, or off

　　Early burnout

　　Early burnout detection for thermocouples (when selected) EBD indicated when loop resistance increase is > 50Ω

　　Output range

　　4 to 20mA nominal into 600Ω max. Out of range characteristic - MTL or NAMUR NE43

　　Maximum lead resistance (THC)

　　600Ω

　　Response time

　　Typical 500 ms

　　LED indicator

　　Green: EBD alarm indication, power and status indication Yellow: alarm indication

　　Maximum current consumption (with 20mA signal)

　　50mA at 24V

　　Power dissipation within unit (with 20mA signal)

　　1.2W at 24V

　　Safety description

　　Refer to certificate for parameters. Um=253V rms or dc

　　Configurator

　　A personal computer running MTL PCS45 software with a PCL45USB serial interface.