signal converter 5v to 4-20 ma, 0-5V to 4-20mA Signal Conversion Module V/I Voltage Converter to Current Board, Analog V/I Converter Output Board: Amazon.co.uk: Business, Industry & Science
MCP3428 8-Channel 4-20mA 16-Bit Current Receiver with IoT Interface at MG Super Labs India
Raspberry Pi and the PI-SPI-2AO 4-20mA Output Interface – Widgetlords Electronics