BD Sensors PCB+ User manual

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Power supply : …………………………………………………………
Range : …………………………………………………………
Pressure overload : …………………………………………………………
Accuracy : …………………………………………………………
Technical inspection of offset : …………………………………………………………
Technical inspection of range : …………………………………………………………
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BD SENSORS s.r.o. • Hradišťská 817 • 687 08 Buchlovice • Tel. [phone] • 572 432 116 • E-mail: [email protected]
PCB2 Rev. 5/04
Operating instructions for
Pressure sensor, PCB+ type, two wires, 4 … 20 mA
Description
Pressure sensors of the PCB+ type are used to measure very small pressures (relative and differential ones). The
measured pressure is sensed by a semiconductor strain-gauge sensor or a ceramic capacitive sensor. The sensors are
designed for gases. In case of a semiconductor sensor, gases have to be non-aggressive and dry.
The sensors are not manufactured in the EX design.
The sensors are adjusted at the factory. Further calibration has to be performed according to calibration instructions.
Selected technical parameters:
Pressure ranges: 0.6 kPa to 100 kPa
Accuracy: 0.5% (1%) of range according to range and type of used sensor
Supply voltage range: 19 to 31 VDC (12 to 31 VDC for sensor without display)
Influence of supply voltage on accuracy: max 0.05% of range / 10 V
Output signal: 4 to 20 mA, two wires (max. load ((Un (V) - 19) / 0.02) Ω)
Influence of load resistance: max.0.05% of range / 10 V
Power polarity reversal resistance and short circuit resistance at the output: permanent.
semiconductor sensor capacitive sensor
Operating range of temperatures : -40°C to 80
°
C 0°C to 60°C
Compensated range of temperatures : 0°C to 60°C 10°C to 40°C
Influence of temperature in the compensated range of temperatures
a. zero: 0.1 … 1.8% of range / 10°C depends on the pressure range and the sensor type
b. range: 0.1 … 1.8% of range / 10°C depends on the pressure range and the sensor type
Material of the box:ABS
Fig. 1 Mechanical dimensions: Fig. 2: Location of terminal blocks and adjusting elements on the
printed circuit board (view with the removed cover of the sensor in
a vertical position)
Mechanical assembly
The sensor should be fixed using four clips on the housing. The sensor cannot be placed in an immediate proximity
of interference sources (transformers, transmitters, motors) and heat sources. Shocks or vibrations at the installation
site can cause an error. Correctly, the sensor has to be mounted in a vertical position (pressure inlets oriented down).
In this position, the sensors are adjusted at the factory. This position prevents a condensate from the penetration into
the sensor. WARNING! Prior to mounting, make sure that there is no liquid in the threaded insert of the closed
valve. Remaining liquid has to be removed properly. The sensor cannot be mounted if there is liquid in the thread.
Connection of the measured pressure (using 1/4“ hose)
The higher pressure is connected to the "+" inlet, the lower pressure to the "-" inlet. In case of a risk of water vapor
condensation, condensation loops have to be created on the hoses. The version of the sensor for measuring the
relative pressure includes only a single inlet. Blowing into pressure inlets is not allowed. Sensors to be used up to
100 mbar can be damaged or destroyed by air pressure from lungs.

Commissioning
Remove the cover of housing. Connect electrical power using the connection terminals (see Fig. 2). Thread the
outlets through the cable gland. The sensor is equipped with the polarity reversal protection.
Fig. 3 Electrical schematics (DC supply U = 19-31 V; without display U = 12 - 31 V)
Display
The display shows data in pressure units or according to user's request. The user can adjust the range of the display.
After switching on, the output signal can be measured. When changing the output signal, two circumstances have to
be taken into account.
1) The starting time is 5 minutes. After that time, the output signal has to be stable at the zero differential pressure
and the constant temperature.
2) For measuring ranges below 100 mbar, the shift of zero occurs due to the change of the sensor position. After
passing the starting time, the error can be reset by zero-setting potentiometers RP2 or RP101.
Settings
In general
When designing the display, a simple operation and a customer control were primarily emphasized. Particular
functions are set by two buttons on the front side via the system of menus.
The settings are permanently saved in the Flash-EPROM memory and can be password-protected against an
unauthorized manipulation.
The indicator of measured values (or individual menus) comprises a four-digit seven-segment display with the
height of digits being 7.62 mm.
Location of control elements and the display
Unit
The unit of the displayed measured value is determined at the time of ordering. By default, bar, mbar and m v.s.
are considered (to be specified when ordering). Nevertheless, the unit can be selected later by attaching one of
the enclosed stickers.
Display of measured values and settings menu
In the center, there is the four-digit display showing the measured value and supporting the configuration. The
measured value is displayed in units defined by the user and depends on the scale and adjusted settings.
Control elements for setting the functions
For the control, two buttons located under a foil can be used. The user moves forward in the menu system or
increases the values on the display by the "▲" button . The "▼" button is used to decrease the values and to
move backward in the menu system.
The menu system is closed. By scrolling the particular menu settings forward and backward, the desired set-
point can be achieved.
By pressing the buttons for a longer time (> 5 seconds), the pulse rate is increased.
By simultaneous pressing of both the buttons,
-the display mode is changed to the configuration mode,
-the adjusted value is saved
or
-the display mode is restored.
ATTENTION: Adjusted parameters are changed just after changing the display mode.
Erasing the display at a different offset of the pressure sensor
(regardless of the measuring range of the pressure sensor, the pressure reference is necessary)
During the lifetime of the pressure sensor, the offset (nominally set at 4,000 mA) may shift. This phenomenon
can cause that the display shows a signal value which differs from the adjusted beginning of the measuring
range. The control software of the display considers this phenomenon and offers a function to eliminate this
phenomenon.
•The PAof menu should be selected. Both the buttons should simultaneously be pressed.
•The number 0247 should be entered to select the special function.
•Both the buttons should be pressed simultaneously again. The following sample value appears on the
display.
•Now, the pressure sensor has to be pressurized via the pressure reference. The pressure has to
correspond to the beginning value of the measuring range.
•When pressing both the buttons simultaneously afterwards, the current output signal of the sensor is
saved as an offset. From this moment, the adjusted beginning of the measuring range (zero-point)
appears on the display, although the sensor signal is shifted in the offset.
ATTENTION: Please note that the output signal remains unaffected by this change. Furthermore, the shift of the
range value ("Full Scale") is performed simultaneously with the shift of the offset.

Change of the display at different range of pressure sensor
(regardless of the measuring range of the pressure sensor, the pressure reference is necessary)
During the lifetime of the pressure sensor, the value of the range being nominally at 20,000 mA e.g., might be
shifted. This phenomenon could cause that the display shows a signal value which differs from the adjusted
boundary of the measuring range. In the control software of the display, this phenomenon was considered and
a function eliminating this phenomenon was implemented.
•The PAof menu should be selected.
•Both the buttons should simultaneously be pressed.
•The number 0238 should be entered to select the special function.
•Both the buttons should be pressed simultaneously again. The following sample value appears on the
display.
•Now, the pressure sensor has to be pressurized via the pressure reference. The pressure has to
correspond to the ending value of the measuring range.
•When pressing both the buttons simultaneously afterwards, the current output signal of the sensor is
saved as a voltage signal. From this moment, the adjusted ending of the measuring range (end-point)
appears on the display, although the sensor signal is shifted in the voltage signal.
ATTENTION: Please note that the output signal remains unaffected by this change.
Entering the data of the basic adjustment of the mechanism ("Load Defaults")
The control system of the display is equipped with the possibility to re-create the adjustment of the mechanism.
That way pre-made changes related to the compensation of the offset or the voltage can be performed
retroactively.
•To load the basic adjustment, the PAof menu should be selected.
•Then, both the buttons should simultaneously be pressed.
•The number 0729 should be entered to select the special function.
•Both the buttons should be pressed simultaneously again. The following sample value appears on the
display,
•If both the buttons are simultaneously pressed again, the basic adjustment of the mechanism is
activated again.
Restrictions on entering a password
Dealing with special functions for the compensation of the offset, the range, recording the basic adjustment and
password change, various codes have been entered to call the function.
ATTENTION: Please note that these codes cannot be used as passwords.
Structure of the menu system

Adjustment of the access security - secured status
If the password is activated, the user is asked to enter the
unlock code after pressing both the control buttons to make
settings in the menu system.
Adjustment of the password security - unsecured status
If not activate, the password can be activated by pressing
both the buttons simultaneously and entering
a predetermined secret number. In settings of the
mechanism, 5 is the secret number. To change this number,
both the buttons should be pressed simultaneously in this
menu. Then, the number 0835 should be adjusted by the
cursor. Afterwards, both the buttons should be pressed
simultaneously again, and the secret number within 0 and
9999 should be adjusted by cursor buttons. The number is
confirmed by pressing the cursor buttons simultaneously.
That way, the new password is adjusted. To activate the
password protection, instructions given in the PAon menu
should be followed.
Adjustment of decimal point
After pressing of both the buttons simultaneously, position
of the decimal point can be adjusted. The desired position
can be selected using "▲" or "▼" buttons. Pressing both
the buttons simultaneously, the settings are closed.
Adjustment of zero
Pressing both the buttons simultaneously, zero can be
adjusted. The adjusted value is shown when the electrical
output signal of the pressure sensor corresponds to 4 mA
(zero). Pressing both the buttons simultaneously, the
settings are closed.
Adjustment of the ending value
After pressing both the buttons simultaneously, the ending
point can be adjusted. The programmed value is shown
when the electrical output signal of the pressure sensor
corresponds to 20 mA (the ending point). Pressing both the
buttons simultaneously, the settings are closed.
Adjustment of attenuation (filter)
After pressing both the buttons simultaneously, the time
interval for updating the displayed value can be adjusted.
The range of the adjustment is from 0.3 to 30 seconds. To
close the configuration, both the buttons should be pressed
simultaneously.
Activation of report about exceeding the range
After pressing both the buttons simultaneously, the report
about exceeding or failing to meet the display range can be
activated. Only the "ON" status or the "OFF" status can be
selected. Pressing both the buttons simultaneously, the
settings are closed.
High-Pressure
After pressing both the buttons simultaneously, the
maximum pressure saved during the measurement is
displayed. If both the buttons are within one-second interval
pressed again, the saved value is deleted. Please note that
the value does not stay saved when the power supply is
interrupted (current loop).
Low-Pressure
After pressing both the buttons simultaneously, the
minimum pressure saved during the measurement is
displayed. If both the buttons are within one-second interval
pressed again, the saved value is deleted. Please note that
the value does not stay saved when the power supply is
interrupted (current loop).
Transport and storage
The range of storage temperatures: -10°C to +50°C
When transporting, make sure that both the inputs of differential pressure sensors are open.
Calibration instructions
Required equipment: pressure gauge: (e.g., high-precision digital pressure gauge)
pressure source: (e.g., a pump, a bag)
power supply: according to the design of the pressure gauge
measuring device: mA-meter for measuring the output signal.
Output settings
1) The sensor should be connected to the corresponding power supply (see operating instructions). Instead of
a load resistor and a voltmeter, a suitable mA-meter of the accuracy class at least 2 times better than the sensor
should be connected.
2) After switching on, the starting time should be let to pass (see operating instructions).
3) Adjusting zero (trimmers RP2 or RP101)
When adjusting zero, both the pressure inputs have to be open. The output current is adjusted to 4 mA by the
RP2 trimmer or the RP101 trimmer (only one of them is available).
4) Adjusting range (trimmers RP1 or RP102)
The nominal pressure is set on the pressure source. This pressure is connected to the inlet "+" (at over-pressure)
or to the inlet "-" (at under-pressure). The output current is adjusted to 20mA by the RP2 trimmer or the RP101
trimmer (only one of them is available). If necessary, the procedure according to points 3) and 4) is repeated.