MA-21 20 mA Current loop converter … Conversion between 20 mA current loop and RS-232 … Transmitter and receiver can be configured as active or passive … Galvanic isolation … Transient suppression … Ensures communication over long distances and in environments with high levels of interference … Code independent/transparent … AC-/DC-supply … Reliable performance and function Field of application 166 MA-21 is used in point-to-point applications where interface conversion from a 20 mA current loop to RS-232 is required to permit communication between different devices. In some cases the converters are used for connection in loops, these are then limited to a total of 6 connected devices. The converter can be set “active” to supply the line with current or “passive” depending on how the connected device is configured. Date rates up to 19.2 kbit/s and transmission ranges up to 6 km (3.73 mi) are possible depending on the data rate. MA-21 is designed as a table top device. Converter, 20 mA current loop www.westermo.com

Application Also see application on page 45 Interface DIP-switches Accessible under lid LED indicators Mechanical Dimensions (W x H x D) Weight Assembly Degree of protection 161 x 53 x 139 mm (6.34 x 2.09 x 5.47 in) AC 0.5 kg (1.10 lb) DC 0.3 kg (0.66 lb) Table top IP 20 RS-232 Up to 19.2 kbit/s Line connection ±20 mA balanced current loop Power Operating voltage Rated current Rated frequency Connection www.westermo.com MA-21 AC 107 – 132 VAC 207 – 264 VAC 22 mA @ 230 VAC 48 – 62 Hz Power MA-21 DC 12 – 36 VDC 140 mA @ 12 VDC DC Detachable screw terminal Converter, 20 mA current loop 167