Presys PCA-570-RM Technical Manual page 50

46
Fig. 32 - Transmitter powered by external source
®
mA + HART input (internal resistor enabled)
®
For the connections shown in figures 31 and 32, use the option mA INPUT + HART and INTERNAL
RESISTOR enabled. In this mode, the 250 Ω HART
®
resistor is enabled internally, in series with the calibrator's mA
®
input. The calibrator will be able to measure the transmitter current and also read and set parameters via HART . If
the internal resistor isn't enabled, an external resistor of at least 150 Ω must be inserted in series with the mA input.
To power the transmitter, the PCA-570 TPS supply (Fig. 31) or an external supply (Fig. 32) may be used.