Specific conditions of use - HMT370EX - HMP370EX

HMT370EX User Guide

Document code
M212305EN
Revision
B
Language
English
Product
HMT370EX
Document type
User guide
CAUTION Potential risk of sparking from aluminum alloy enclosure. The equipment shall be installed in such manner as to prevent the possibility of sparks resulting from friction or impact against the enclosure.

Wiring requirements

  • The cable glands and blanking elements used with the transmitter shall conform to requirements of ANSI/UL 60079-0.
    • Unused lead-throughs must be sealed using Ex compliant blanking elements.
  • 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).
CAUTION Connect only de-energized wires. Never switch on the power supply input before completing the wiring and closing the transmitter body.
WARNING Review the FM Approvals wiring requirements for intrinsically safe operation in FM Approvals control drawing before installation.

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 1.

Table 1. Intrinsically safe input parameters
Parameter Value Associated apparatus entity parameters
Ui 28 VDC Uo ≤ Ui
Ii 100 mA Io ≤ Ii
Pi 700 mW Po ≤ Pi
Ci 12.1 nF Co ≥ Ci + Ccable
Li 16 µH Lo ≥ Li+ Lcable

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 1. Accessing the test points on the component board requires opening the transmitter enclosure.
Figure 1. Location of test points and service port
1
Multimeter test points for analog output channels 1 and 2
2
Service port for PC connection
CAUTION

The transmitter body enclosure must not be opened in an explosion hazardous area, unless a safe work permit has been issued in accordance with the standard IEC 60079-14. Either remove the transmitter from the hazardous area before opening the enclosure, or ensure that an IEC 60079-14 compliant safe work procedure has been implemented in the hazardous area.

Use an intrinsically safe multimeter that won't cause the intrinsically safe input parameters listed in Table 1 to be exceeded when it is connected in series (current measurement) or parallel (voltage measurement) to the associated apparatus.

Using the service port

The service port (see Figure 1) must only be used in a safe area. Either remove the transmitter from the hazardous area or ensure that a safe work procedure has been implemented in the hazardous area. Only use the Vaisala accessory PC connection cable with the service port.

Maintenance

The probe (includes probe body and head) can be detached and replaced by the user. The probe head filter (see Figure 1) is also user-replaceable. For other maintenance requirements, contact Vaisala.

CAUTION The probe can be detached and changed when HMT370EX is powered. Any other live maintenance, including changing the probe head filter, is not allowed.