This is a RTD Pt-100 Transmitter, It can Convert Thermocouple mV or RTD mV to 4-20 mA Current Transmitter. The output is a current source and not a current sink.
These are the circuits and boards of a Mini Temperature Transmitter for a Platinum hundred ohms temperature Sensor. The customer wanted a two wire system, this needs low power opamps
Below is a Electrical Control Panel, It has a Strip Chart Recorder which is electro-mechanical, It has a PLC Inside. A handheld PLC Programming unit. The computer is showing the