Calibration resistors R4 and R5 along with the RT1 and RT2 RTD sensors can sink this current when the corresponding GPIO pin is driven low. When not used, the GPIO pins are tri-stated. The voltage ...

Equipment needed for calibration of the RTD transmitter includes: Precision DMM with mA accuracy of ±0.002 and mA resolution of 0.001; Precision RTD simulator; Precision Decade Resistance Box with ohm ...