Why minimum 250 ohm loop resistance is required for HART Field Bus Protocol Device? скачать в хорошем качестве

Why minimum 250 ohm loop resistance is required for HART Field Bus Protocol Device?

This video describes why Highway Addressable Remote Transmitter (HART) field bus protocol devices require minimum 250 ohm loop resistance. Advantages of HART field bus devices. HART - Master and slave and multi drop communication. HART current signal 1 mA P-P is converted to minimum 0.25 mV P-P using 250 ohm resistor and this 250 ohm minimum resistor is as per the HART standard. The upper limit 1100 ohm is not fixed and this limit vary according to loop resistance, minimum voltage required for transmitter operation and DC power supply voltage. Video Link1:    • What is the purpose of 250 ohm resistor at...   What is the purpose of 250 ohm resistor at the output of 4 to 20 mA Transmitter? Video Link2:    • Two wire Transmitter   Two wire Transmitter loop resistance calculation for voltage drop