Vaisala HMT310 - Manual (Page 21)

Chapter 3 ________________________________________________________________ Installation
VAISALA ________________________________________________________________________ 21
CHAPTER 3
INSTALLATION
This chapter provides you with information that is intended to help you
install the HMT310.
Measuring at Overpressure
HMT314 and HMT318 are designed for humidity measurement at
overpressure. The maximum measurement pressures depend on the probe
as follows:
- HMT314: 0 ... 100 bar (10 MPa), for pressurized rooms and processes,
probe is provided with a nut, fitting screw and sealing washer
- HMT318: 0 ... 40 bar (4 MPa), for pressurized pipelines, ball valve set
available
The actual pressure in the process or sampling cell needs to be set to the
transmitter by using the serial line command PRES (Set Ambient
Pressure for Calculations).
CAUTION In pressurized processes it is essential to tighten the supporting nuts and
screws very carefully to prevent loosening of the probe by the action of
pressure.
Pressure Regulator Recommended
When sampling pressurized processes exceeding the maximum
measurement pressure of the probe, the pressure in the measurement
chamber must be regulated to acceptable level or below. It is
recommended to use a pressure regulator before the measurement
chamber to prevent significant pressure variations.
Selecting Location
Finding a suitable site for the Humidity and Temperature Transmitter
HMT310 is important for getting representative ambient measurements.
The site should represent the general area of interest.