Vaisala PTB110 User Manual
PRODUCT DESCRIPTION
Normal Mode
USER'S GUIDE
Vaisala BAROCAP®
Barometer PTB110 Series
– Several pressure ranges
– Accuracy ±0.3 hPa at +20 °C
– Long-term stability ±0.1 hPa/year
– On/off control with external trigger
– Output voltage 0 … 2.5 or 0 … 5 VDC,
frequency output
– Current consumption less than 4 mA
– Mountable on a (35 mm wide) DIN rail
– NIST traceable (certificate included)
– BAROCAP
®
sensor
The PTB110 barometer is a micro controller based barometer
including a voltage or frequency output. The barometer can be
supplied with several pressure ranges. The output of the
barometer is a calibrated barometric pressure reading.
The barometer uses the Vaisala BAROCAP
capacitive sensor developed by Vaisala for barometric pressure
measurement applications. The BAROCAP® sensor is especially
designed for accurate and stable measurement of barometric
pressure.
®
Sensor, a silicon
INSTALLATION
The PTB110 barometer is intended to be installed indoors.
Installing outdoors requires a protecting enclosure. A DIN rail
mounting option enables the mounting of the barometer on a 35
mm wide standard DIN mounting rail.
The barometer should be installed in a vertical position with the
connectors pointing downwards to prevent accumulation of
condensated water
.
The device is in the normal mode when the power on
jumper is connected (see figure on the following page).
In the normal mode the barometer measures
continuously when powered-up.
Shutdown Mode
The device is in the shutdown mode when the power
on jumper is not connected.
In the shutdown mode, the barometer can be turned on
or off by switching the pin 1. The pin 1 is located at
the customer port, on the left edge of the screw
terminal.
NOTE The other jumpers inside the barometer are
set at the factory and they must not be
touched.
ELECTRICAL CONNECTIONS
The PTB110 barometer contains a screw terminal block located at
the customer port. The screw terminal includes the electrical
input/output pins presented in the table below.
Pins in screw terminal Description/Value
Pin 1: EXT_TRIG External trigger input
Pin 2: AGND Analog ground
Pin 3: GND Ground
Pin 4: SUPPLY Supply voltage
Pin 5: VOUT/FOUT Voltage output/
In the normal mode no connection to the Pin 1 EXT_TRIG is
recommended.
Pin 1 is used as a power on/off
switch in shutdown mode as
follows:
Power off 0 VDC
Power on 5 VDC
Frequency output
OPERATING MODES
The PTB110 barometer has two operating modes, the normal
and the shutdown mode. The factory setting is the normal mode
.
The barometer is protected against a reverse operating voltage.
Both grounds (AGND and GND) are in the same electrical
potential in the barometer. Both three-wire and four-wire
connections can be used. However, it is recommended to use the
four-wire connection, especially if the signal wires are long.
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The connections can be made as illustrated below.
−
INSERTING AND REMOVING THE COVER
ADJUSTMENT AND CALIBRATION
READING THE OUTPUT
The barometric pressure (P) can be calculated from the measured
output voltage (Uout) using a simple equation.
P
range
PP ⋅+=
low
U
where:
= Lower limit of the pressure range [hPa]
P
low
P
= Pressure full range [hPa]
range
= Voltage full range [V]
U
range
U
= Measured output voltage [V]
out
Example
Pressure range 500...1100 hPa
Voltage output 0...5 V
Measured output voltage 4 V
hPaP 9804
500 =⋅
NOTE The low end of the output voltage range of
In the frequency output 1 hPa equals 1 Hz.
U
range
+=
the barometer saturates at about 50 mV.
out
()
hPa
5001100
V
5
hPaV
The adjust buttons and the power on jumper are located inside
the barometer. In order to adjust the measurement, the plastic
cover of the barometer must be removed.
For safety reasons, turn off the power when opening the cover.
You can power off the device by pulling out the connector from
the customer port. Correspondingly, you can power on the
device by plugging the connector back into the customer port.
Removing the Cover
Stick a flat-end screwdriver between the cover and the metal
mounting plate. As you press the tool slightly, the cover will
open up.
Inserting the Cover
Place the short and solid side of the cover against the left edge of
the metal plate. Ensure that the metal clamps slide into the
hollows in the cover. Then press the cover against the metal
plate until it clicks in place.
INNER STRUCTURE OF THE BAROMETER
Calibration of the PTB110 series barometers is NIST traceable
and the barometers are supplied with a NIST traceable
calibration certificate.
There are two push buttons available for the offset fine
adjustment inside the barometer (see the figure on the previous
page). The adjustment step is 0.05 hPa.
OPERATING THE BUTTONS
Restoring Adjustments
To restore the adjustments, press and hold down the left button
while switching on the barometer. After releasing the button, a
green LED starts flashing.
When the factory adjustments are in use, the green LED flashes
twice. When the user adjustments are in use, the green LED
flashes three times.
Now you can change the factory adjustments to user adjustments
or vice versa by pressing the left button.
Return to the normal operating mode by switching the power off
and on in sequence.
Using Analog Output Test Mode
To activate the test mode, press and hold down the right button
while switching on the barometer.
The function forces the voltage or frequency output to 50% of
the scale. As an indication of the test mode, the red LED is lit.
Return to the normal operating mode by switching the power off
and on in sequence.
Offset Correction
To activate the offset correction mode, press and hold down both
buttons switching on the barometer.
The green and red LEDs are lit. Now you can adjust the offset
correction upwards or downwards.
Each time when pressing the left button, the offset
goes down by one step (5 Pa), and the green LED
flashes once.
Each time when pressing the right button, the offset
goes up by one step (5 Pa), and the red LED flashes
once.
Return to the normal operating mode by switching the power off
and on in sequence.
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