- -
10
4.
PROBES
AND
MEASUREMENTS
The instrument measures absolute, relative and differential pressure using the PP471 SICRAM
module and the TP704 and TP705 series probes. It also measures the temperature with a Pt100
sensor fitted with SICRAM module, or with direct 4 wire Pt100 probes.
The SICRAM module acts as an interface between the sensor on the probe and the instrument.
There is a microprocessor circuit with a permanent memory inside the module that enables the
instrument to recognize the type of probe connected and to read its calibration information.
The probes are detected during turn on, and this cannot be performed when the instrument is
already on, therefore if a probe is connected and the instrument is on, it is necessary to turn it
off and on
.
The probes fitted with SICRAM module are calibrated in the factory; no calibration is required by
the user.
4.1
PP471
MODULE FOR PRESSURE MEASUREMENT
The PP471 module acts as an interface between the TP704 and TP705 series Delta Ohm probes and
the instrument.
The
TP704
series pressure probes have a 1/4" BSP threaded male connection, and must be screwed
into the system using the necessary sealing gaskets.
The
TP705
series have two Ø5 connections where the suitable tubes are inserted in order to perform
the desired measurement.
Caution!
Please pay careful attention to the joint pressure sealing; use suitable gaskets and joints.
The threaded connection is protected by a plastic cap. Put it back after use as it protects the pressure
cell from foreign bodies.
IMPORTANT! Ensure the probe's bottom scale is higher than the pressure that will be
measured. In case this value is unknown, start by using higher-capacity probes.
For every pressure probe a range of overload pressure and a burst pressure are declared:
pressures in the range of overload pressure don’t cause the break of the sensor but the
declared accuracy can be overcome. Pressure over the stated burst pressure may break the
sensor. The application of higher pressures than the overload pressure limit, although lower
than the burst pressure, may produce permanent damage to the probe (e.g. offset shift). Never
exceed the stated burst pressure.
Please see the technical characteristics of the probes on paragraph “Technical characteristics”.
Upon turning on the instrument automatically detects the PP471 module. The probe's type
(absolute, relative or differential) and bottom scale value are detected even when the instrument is
on (see chapter 3).
To change the instantaneous or peak value unit of measurement, press UNIT. The following units of
measurement are available:
Pa, hPa, kPa, mbar, bar, atm, mmHg, mmH
2
O, kgf/cm
2
, PSI, inchHg.
Some units of measurement require a degree of multiplication:
the "-3" symbol indicates the displayed value must be divided by 1,000;
the "3" and "6" symbols indicate the displayed value must be multiplied respectively by 1,000
or by 1,000,000.
The instrument does not automatically detect the probes which are not fitted with SICRAM module.
