Vaisala HMT370EX - Table 13 Intrinsically Safe Input Parameters

• Select a strain relief option that suits the application (either use cable glands that include
strain relief or install separate clamps: see IEC 60079-14).
• Japan: Use only cables suitable for +80°C (+176 °F).
Connect only de-energized wires. Never switch on the power supply
input before completing the wiring and closing the transmitter body.
CAUTION!
Intrinsic safety
The overvoltage category of HMT370EX transmitters is I (non-mains equipment), and ambient
pollution degree is 4, as specified in IEC 60664-1. For intrinsically safe input parameters, see
Table 13 (page 30).
Table 13 Intrinsically safe input parameters
Parameter Value Associated apparatus entity
parameters
U
i
28 VDC U
o
≤ U
i
I
i
100 mA I
o
≤ I
i
P
i
700 mW P
o
≤ P
i
C
i
12.1 nF C
o
≥ C
i
+ C
cable
L
i
16 µH L
o
≥ L
i
+ L
cable
Using analog output test points
There are test points for measuring the voltages and currents of the analog outputs, located
above each screw terminal block as shown in Figure 8 (page 31). Accessing the test points on
the component board requires opening the transmitter enclosure.
HMT370EX User Guide M212305EN-B
30