Airflow PT-LE User manual

1
Differential Pressure
Transducer PT-LE
Operating Instructions

Operating Instructions PT-LE
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Inhalt
1. Safety Instructions............................................................... 4
1.1. Use for Intended Purpose Only ............................................................. 4
1.2. Transport, Installation, Connection and Startup .................................... 4
1.3. Malfunctions, Maintenance, Repairs, Disposal...................................... 4
1.4. Symbols................................................................................................. 5
2. Description oft he Transducer............................................ 6
3. Startup................................................................................... 6
3.1. Functional Description ........................................................................... 6
3.2. Supply Voltage Connections in the Appliance: ...................................... 6
3.3. Connections for Two-Wire System: ....................................................... 7
4. Resetting Offset ................................................................... 7
5. Configuring the Output Signal ........................................... 8
6. Setting the Measuring Range (Option).............................. 8
7. Display (Option) ................................................................... 9
8. Setting the Relay Operating Point (Option) ...................... 9
9. In case of Malfunctions ....................................................... 9
10. Technische Daten .............................................................. 10
11. Dimensional Drawing ........................................................ 11

Operating Instructions PT-LE
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Significance of the Operating Instructions
These operating instructions go into the function and handling of the PT-LE
differential pressure transducer
Use at variance to the purpose of the transducer and its incorrect operation may
result in risks arising for both people and assets. That is why each and every person
charged with handling the transducer must be instructed in its use and is to be aware
of the dangers. Close attention must be given to these operating instructions and, in
particular, to the associated safety instructions. Do contact the manufacturer
should you not understand all the sections.
Be heedful of the operating instructions:
xThey must be readily available during the entire service life of the transducer.
xThey must be passed on to the succeeding personnel charged with
operations.
xAny additions coming from the manufacturer must be inserted.
The manufacturer reserves the right to refine this type of appliance without having to
document this fact in each particular instance. The manufacturer is more than willing
to provide you with information on the updated nature of these operating instructions.
Conformity
This transducer conforms with the present stage reached in technical
engineering. It complies with the statutory requirements of the EC
directives. This is documented from the CE mark being affixed.
© 2015
The copyright to these operating instructions rests with the manufacturer. They
include specifications, instructions and drawings on the function and handling of the
transducer. Neither in their entirety not in part are they to be duplicated or made
available to third parties.

Operating Instructions PT-LE
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1. Safety Instructions
1.1. Use for Intended Purpose Only
The PT-LE differential pressure transducer registers both differential pressure and
positive/negative gauge pressure.
The operational requirements on the rating plate and in the "Specifications" chapter -
and the safe supply voltage in particular - must be kept to.
The transducer is only to be handled in conformity with these operating instructions.
No modifications to the transducer are permitted. The manufacturer is not liable for
damage arising from any incorrect use or one at variance to the intended purpose.
Claims to warranty in such an instance would be forfeited.
1.2. Transport, Installation, Connection and Startup
Do not block the pressure inlets on the transducer being moved! Changes in
barometric pressure may damage transducers with low measuring ranges.
Only qualified personnel are to assemble the appliance and see to its electrical
connections. They must be instructed as such and be assigned by the plant operator.
Only instructed persons as assigned by the plant operator are to operate the
transducer.
Do not perform any functional test involving compressed or breathable air. This
would otherwise damage those transducers with low measuring ranges.
Measurement errors may occur should the appliance not be protected from sunlight.
Specific safety instructions are given in the individual chapters.
1.3. Malfunctions, Maintenance, Repairs, Disposal
Malfunctions which cannot be put right as specified in Chapter 8 and damage at the
appliance itself must be immediately reported to the qualified personnel with
responsibility for the electrical connections.
The appliance must be taken out of service by the qualified personnel responsible
until the malfunction has been put right and also secured against being
unintentionally used.
Always switch off the power to the appliance before it is opened!
The appliance does not need any maintenance.
Only the manufacturer is to carry out repairs.
The electrical components of the transducer contain both environmentally hazardous
materials and materials that can be reused. That is why the appliance is to be
recycled once it is finally immobilized. The environment directives on this from the
country in question must be followed.

Operating Instructions PT-LE
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1.4. Symbols
The symbols below in these operating instructions point to the risks, which could
arise in handling the equipment:
WARNING! It points to a hazard possibly extending from injures through
to death should the instructions not be followed.
CAUTION! It points to a hazard which could cause considerable
damage should the instructions not be followed.
INFORMATION! This indicates information, which is vital for proper
appliance operations.
da

Operating Instructions PT-LE
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2. Description oft he Transducer
Type PT-LE differential pressure transducers are pneumatic/electrical sensors for
pressure testing (positive/negative gauge pressure and differential pressure)
purposes. They are typically used in air-conditioning and ventilation technology e.g.
pressure testing in ventilation ducts. The transducer's core is a piezoresistive
pressure transducer.
3. Startup
3.1. Functional Description
PT-LE pressure transducers are of the precision type and despite their sturdiness
they should still be treated with care. Installation right next to heat and radiation
sources e.g. radiators should be avoided as this may lead to measurement errors
arising. Ideally the appliance should be vertically mounted on a wall not subject to
any vibrations. To stop any condensed water entering the measurement cell, the
transducer together with the hose connections for positive gauge pressure + and
negative gauge pressure - should be pointing downwards.
The right pressure sign must be used in keeping with the following table when
connecting the pressure to the transducer:
Type of pressure
Connect pressure to
Example
pos. gauge pressure + input 0…1 kPa
neg. gauge pressure - input 0…-500 Pa
Differential pressure Higher pressure at + input
lower pressure at - input
0…125 e.g via a differential
pressure producer (e.g. measuring
orifice)
Symmetrical pressure ranges + input ±200 Pa
Asymmetrical pressure ranges Input of the larger pressure
range
-300 Pa…+1 kPa
(here connect to + input)
3.2. Supply Voltage Connections in the Appliance:
Fig 1: Position of components (not every component is shown)
5 4 3 2 1 5 4 3 2 1
One measurement range Four measurement ranges

Operating Instructions PT-LE
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Note the prescribed supply voltage (see rating plate). Also follow the
connection diagram on the appliance cover / circuit board mount.
ST4
Pin
Connection-
name
Meaning
Two-wire
1
24V
Power supply input - 24VAC/DC
+terminal
15-32VDC
2
GND
Ground for power supply
Not used
3
OUT
Voltage or current output
-terminal
4
GND
Ground for output signal
Not used
5
SET 0
Zero-point input (+24V zero-point is active)
Zero-point input
The transducer outputs are protected from short circuits. The DC-supplied appliances are
protected from reverse polarity of the supply voltage.
3.3. Connections for Two-Wire System:
5 4 3 2 1 5 4 3 2 1
4. Resetting Offset
After starting the pressure transducer, give it some 15 minutes to
warm up. During this time the output signal may be unstable.
Zero-point calibration of the appliance is only effected via the input assigned for this
purpose. The user must ensure that the appliance is not subjected to any pressure
during the calibration process as this might lead to a wrong offset value which, in turn,
would result in a wrong output signal. The 24V input makes it possible to activate a
3/2 directional control valve with the same signal, which switches the PT-LE's
pressure inputs at zero pressure during the zero calibration process. In this case the
zero point calibration signal must be applied until there is no doubt that the pressure
has fallen to zero.
One measurement range Four measurement ranges

Operating Instructions PT-LE
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5. Configuring the Output Signal
The user can configure the PT-LE's output signal. This can be done in various ways
Output
SW Pos 3
SW Pos 4
Comments
0…10V
on
off
RLast!Nȍ
2…10V
on
off
RLast!Nȍ
0…20mA
off
off
max. load ȍ
4…20mA
off
on
max. load ȍ
The two-wire model must be configured by the manufacturer.
6. Setting the Measuring Range (Option)
The transducer with 4 measuring ranges can be adapted to the measuring
assignment in question. The teaching of 4 measuring ranges into the appliance has
been undertaken by the manufacturer. The switches 1 and 2 of SW can be used to
select the measuring range in question before the transducer is switched on.
SW Pos 1
SW Pos 2
Measuring
range
off
off
1
on
off
2
off
on
3
on
on
4
The limiting values of the measuring ranges are noted on the label on the side of the
PT-LE. Display-optional appliances indicate the limiting value of the selected
measuring range for 1.5 seconds after being switched-on. The appliance should be
re-zeroed following any measuring range change-over. This is because the
amplification change-over may produce offset voltages.
Pos 1 Pos 2

Operating Instructions PT-LE
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7. Display (Option)
To show up the readings, the PT-LE can also be fitted out with a display. The
readings will be shown in either Pa or kPa depending on the limiting value of the
measuring range. The number of the measuring range selected is always shown on
the bottom line of the display.
On switching on a display-equipped appliance, the first thing shown is the PT-LE
programme version followed by a 1.5 second screening of the limiting value of the
selected measuring range and then the actual readings.
8. Setting the Relay Operating Point (Option)
The relay operating point can be adjusted with the aid of the P2.1 potentiometer.
Adjustment is easiest when the desired switching pressure is applied and the
potentiometer set so that the relay is just triggered.
Please note: The relay is connected to the sensor's output so that any adjusted
time delay will also cause a delay in relay triggering.
9. In case of Malfunctions
Fault descritpion
Possible cause
Corrective action
No output signal
- Supply voltage is not
connected
- Incorrect supply voltage
connected
- Defective input protection diode
Only for DC power:
- defective reverse polarity diode
- Connect correct supply voltage
- Connect correct supply voltage
(see rating plate)
- Send the appliance to the manufacturer
for repairs
- Send the appliance to the manufacturer
for repairs
Output signal is
constant despite
change in pressure
- Defective output protection
Diode
- Pressure ports reversed
- Send the appliance to the manufacturer
for repairs
- Connect the pressure as described in
„3. Installation“
Output signal
incorrect
- Faulty pressure sensor
- Zeroing with pressure applied
For current output:
- load too high
For voltage output:
- load resistance too low
- Send the appliance tot he manufacturer
for repairs
- Renewed zeroing without pressure
- Note maximum ȍload
- Note minimum 50 k load resistance ȍ
(see „7 Specifications“)

Operating Instructions PT-LE
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10. Technische Daten
Linearity: 2.0 % of the measuring range limiting value
t.c. offset: +/- 0.1 %/°C
t.c. span: +/- 0.1 %/°C
Accuracy: 2.0 % of the measuring range limiting value
Measuring ranges: +/-2.5 kPa (+/-250 Pa…2.5 kPa)
+/-10 kPa (+/-5.0 kPa…10 kPa)
+/-100 kPa (+/-20 kPa…100 kPa)
As an option, the customer can use a DIP-switch to select 4
pre-set measuring ranges.
Min. response time: 20 ms
Pressure ports: Nominal 4 or 6 mm width for hose
Output signals: 0/2…10 V or. (RL> 50 k Ohm)
0/4…20 mA (RL< = 500 Ohm)
4…20 mA (two-wire 17…32 V,RL< = 500 Ohm)
Switching contact (optional): max. 230 VAC, 6 A; min. 500 mW
Display (optional): 3½-digit LCD
Overload range: from 2.5 kPa Æ50 kPa
2.5 kPa … 10 kPa Æ140 kPa
> 10 kPa Æ200 kPa
Storage temperature: -20°C...+70°C
Working temperature: -20°C...+60°C, with Display 0°C…50°C
Supply voltage: 24 VDC/VAC +/-15 % (no galvanic isolation)
15 … 32 VDC (two-wire) (no relay output)
Power consumption: approx. 1 W
Operating position: vertical preference
Housing: see drawing
Protection class: IP 65
Installation: The appliance can be installed either on a top-hat rail or on a
wall with fastening holes
Testing: EN 61000-4-2, EN 61000-4-3…-6,
EN 61000-4-11, EN V50204

Operating Instructions PT-LE
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11. Dimensional Drawing
no LCD with LCD

The Observator range is in continuous development and so specifications may be subject to change without prior notice.
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