WIKA PGT15 User Manual
Page 4
11412101 09/2009 GB/D/F/E
WIKA Operating instructions intelliGAUGE Model PGT15 (LOG-1x)
4
GB
1. Safety instructions / 2. Operating principle
1. Safety instructions
The appropriate national safety regulations (e.g. EN 837-2
"Selection and installation recommendations for pressure
gauges") must be observed when installing, commissio-
ning and operating these devices.
Serious injuries and / or damage may occur should the appropriate
regulations not be observed.
Only appropriately qualified personnel should work on these
instruments.
The effective maximum surface temperature is not dependant upon
the device, but mainly on the temperature of the respective pressu-
re medium! In the case of gaseous substances, the temperature
may increase due to compression warming. In these cases it may
be necessary to throttle the rate of change of pressure or reduce
the permissible temperature of the pressure medium.
2. Operating principle
Bourdon tubes are widely used as measuring elements for technical
pressure measurement due to their robustness and ease-of-use. Under
the influence of pressure these measuring elements will deform within
their elastic range.
This movement is converted into a rotary motion by means of a mecha-
nical movement (gear). A "masking element", mounted on the pointer,
rotates with the instrument pointer in direct linear proportion to the pocess
pressure. The electronics, placed opposite the pointer, are equipped with
an infrared LED and infrared photodiodes.
When there is no pressure, the "masking element" on the pointer prevents
the light from the LED reaching the photodiodes. When the pressure incre-
ases, the pointer rotates, and with it, the „masking element“. Thus, as the
pressure rises, successively more photodiodes are illuminated by the light
emmitted from the LED, and this is converted into an electrical signal.
Through the electronics, the signals from the photodiodes which are
proportional to the pointer position are converted into a stepped electrical
output sigal.
An intelliGAUGE line pressure gauge with electrical output signal
combines all the advantages of an on-site display without the need for an
external power supply, with the demands of modern electronic measure-
ment for electrical signal transmission.