Ex ia DP/PA coupler for hazardous-area fieldbus segments
The Siemens 6ES7157-0AD82-0XA0 is a SIMATIC DP field device interface that couples a PROFIBUS DP segment to an intrinsically safe PROFIBUS PA segment per IEC 61158-2. It carries the Ex [ia] rating, meaning the PA-side outputs are limited to intrinsically safe levels — max Uo 15 V, max Io 247 mA, max Po 1.95 W — so it can connect directly to field instruments in Zone 1 or Zone 0 hazardous areas without additional barriers. The coupler supplies up to 110 mA to the PA segment and can drive up to 31 PA field devices at the 31.25 kbit/s transmission rate.
Extended temperature range and physical fit
The 80 mm width, 125 mm height, and 130 mm depth fit a standard IP20 enclosure with DIN-rail mounting — account for the 9-pin Sub-D connector clearance on the front face. Reverse-polarity protection on the 24 V supply is built in, and the 5 ms hold-up time on mains failure keeps the PA segment alive through a brief power dip — useful if the upstream DP master cycles but the PA instruments need to finish a measurement cycle.