Microsensor MDM7000 Operation Manual page 30

g) Avoid nearby high-power electrical equipment and utilize
shielded cables (the shielding layer is well grounded at both
ends).
Warning
For flameproof transmitters, under powered conditions, it is strictly
prohibited to open the rear cover or front glass. Therefore, during
on-site use, hand terminal should not be used to calibrate the
transmitter, but the transmitter buttons can be used for calibration.
5.1.2 2-wire HART communication connection
The communication mode of the transmitter is HART, and a brief
description of the communication connection of the HART transmitter
is as follows.
The output of HART transmitter modulates HART digital signal besides
the 4mA～20mA signal. In the electrical connection diagram between
the transmitter and the external power supply shown in Figure 42, the
HART terminal device can be connected across the "+" and "-"
250Ω
Series resistor
Figure 40
28
Power supply