mensor PCS 400, Руководство по эксплуатации

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3 – MULTIPLE RANGE PNEUMATICS KIT
The pneumatic module can accomodate one, two
or three internal transducers. All three can be of a
common mode, or a mix of gauge and absolute
mode transducers. For example, one frequent con-
figuration is a high and a low pressure primary and
secondary transducer and a Barometric Reference
(absolute) Transducer for the third. This arrange-
ment provides the user with better accuracy for a
second pressure range and allows a fast, conven-
ient means for setting absolute Zero on those two
transducers. This arrangement, and other multi-
range configurations, are shown by the pneumatic
schematics in the
Appendix , figures 9.3 through
9.6. The software provides the user with the capa-
bility to set the system to either AUTORANGE for
automatic best resolution, or to RANGE HOLD to
lock onto a selected transducer. AUTORANGE and
RANGE HOLD are explained in the
Local Opera-
tion and Remote Operation sections of the manual.
The use of the Barometric Reference Transducer is
explained under Option 3a which follows. There
are some design constraints on a multiple range
PCS 400
.
Contact Mensor to discuss the feasibility
of your particular multi-range requirements.
3a – Barometric Reference Transducer
A Barometric Reference Transducer is a special
i n t e rn a l h igh a cc u ra cy ba ro m e t ric ra n g e
transducer. This special transducer will always
have transducer address 02. Normally it is open to
atmosphere only, and is pneumatically isolated
from the system. For some special applications it
is connected to the reference port as shown in
figures 9.4 and 9.5. The purpose of this transducer
is that it can be used as a calibration reference to
quickly set zero for the other absolute pressure
transducers in the system, or it can be used in a
gauge pressure instrument to provide an absolute
emulation mode of operation.
Barometric Calibration
This mode allows the active transducer (other than
the Barometric Reference Transducer, itself) to be
corrected to the same pressure reading as that of
the Barometric Reference Transducer. Obviously,
the Barometric Reference Transducer cannot be
used to calibrate itself. The procedure to accom-
plish the barometric calibration is as follows:
1. Select the transducer to be calibrated as the
active transducer. (See LIMITS–SELECT
ACTIVE TRANSDUCER).
2. Press [2nd] [CAL] to enter the CALIBRATION
MODE (top line of the display).
3. Use [+] and [–] to scroll until the display
shows:
CALIBRATION MODE
CALIBRATE WITH BAROMETRIC REFERENCE
then press [=].
4. Enter the zero password followed by [=].
5. When the password is accepted the display
will prompt ENTER ‘=’. Press [=] once more.
6. The display will show the barometric refer-
ence pressure on the top line, and the active
sensor reading on the bottom line.
7. When both readings are stable except for the
last digit, which may remain nervous, press
[=] to execute the calibration. The barometric
pressure will be copied to the active
transducer.
The calibration of the selected transducer is imme-
diate. The zero offset in memory is immediately
displaced by the new, calculated zero, and the
display returns to the calibration screen shown
above. Press [CE] to return to the previous mode.
3b – Two Independent Internal
Transducers
This option uses a modified pneumatic module
(see figure 9.6 in the
Appendix ) to provide two
independent internal pressure transducers of ap-
proximately the same range in an exclusive
either/or arrangement. The modification allows for
the pressure submitted to the rear panel MEAS-
URE/CONTROL pressure port to be routed to
either the primary transducer (address 0) or to an
alternate transducer (address 1) on command. The
two transducers can be both the same type, or a
mix of absolute and gauge types. The AUTORANGE
feature is disabled for this option.
PCS 400
OPTIONS
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