The MTL5553 has been specifically developed to extend 31.25kbit/s (H1) fieldbus networks into hazardous areas. It provides power and communication to devices powered through the signal conductors. For installations in which the safe-area bus length is small an internal terminator can be enabled by a switch on top of the module. The MTL5553 complies with requirements of Fieldbus Foundation™ specified power supply Type 133† (IS power supply).

　　SPECIFICATION

　　See also common specification

　　Location of fieldbus device(s)

　　Zone 0, IIC, T4–6hazardous area if suitably certified

　　Hazardous-area fieldbus power supply

　　18.4V ± 2% 105Ω ±3% dc impedance 80mA maximum current

　　Maximum cable length

　　Determined by IS requirements, depending on other devices attached and maximum acceptable voltage drop along cable

　　Digital signal transmission

　　Compatible with 31.25kbit/s fieldbus systems and complies with fieldbus standards†

　　Supply voltage

　　20 to 35Vdc

　　LED indicator

　　Green: one provided for power indication

　　Power requirement, Vs, with 80mA output load

　　135mA typical at 24V 105mA at 35V

　　Power dissipation within unit, with 80mA output load

　　2.3W typical at 24V 2.6W maximum at 35V Note: To allow adequate heat dissipation under all likely thermal conditions, it is recommended that MTL5553’s are installed on a horizontal DIN-rail mounted on a vertical surface* with a 10mm space between adjacent units. MTL MS010 10mm DIN-rail module spacers are available for this purpose. * If an MTL5553 is mounted in a non-optimum orientation, the maximum operating temperature is reduced to 45°C.

　　Isolation

　　250V ac between safe- and hazardous-area circuits and power supply

　　Safety description

　　Terminals 1 and 2 22V, 102Ω, 216mA; Um = 250V rms or dc † The applicable fieldbus specifications and standards are: Foundation fieldbus™ 31.25kbit/s Physical Layer Profile Specification, document FF-816, IEC 61158-2: 1993 and ISA-S50.02-1992 for 31.25kbit/s fieldbus systems

　　Note: To assist the process of terminating cable screens, screw terminals have been provided in terminals 3, 6, and 10. Please note, however, that there is no internal connection for these terminals so they are not earthed.