Rotronic PF4 User manual

E-M-PF4-V1_00 Rotronic AG
Bassersdorf, Switzerland
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PF4 Differential Pressure Transmitter:
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© 2014; Rotronic AG E-M-PF4-V1_00
PF4
Differential Pressurep and Temperature Transmitter
Instruction Manual

E-M-PF4-V1_00 Rotronic AG
Bassersdorf, Switzerland
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PF4 Differential Pressure Transmitter:
Instruction Manual
Instruction Manual
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Document Title
© 2014; Rotronic AG E-M-PF4-V1_00
Contents
Contents............................................................................................................................................................2
1Overview ..............................................................................................................................................4
2Dimensions..........................................................................................................................................5
3General Description............................................................................................................................6
3.1Power Supply ...................................................................................................................................6
3.2Differential Pressure Measurement ..................................................................................................7
3.3Pt100 Connection ...........................................................................................................................11
3.4HC2 Connection .............................................................................................................................11
3.5Analog Outputs...............................................................................................................................12
3.6Relay ..............................................................................................................................................14
3.7Service Interface.............................................................................................................................14
3.8Display and Keys............................................................................................................................15
3.9HW4 Software Compatibility...........................................................................................................16
4Mechanical Installation.....................................................................................................................17
4.1General...........................................................................................................................................17
4.2Housing ..........................................................................................................................................17
4.3Mounting.........................................................................................................................................18
4.4Differential Pressure Connection ....................................................................................................18
4.5HC2 / Analog Connection ...............................................................................................................19
4.6Pt100 Connection ...........................................................................................................................21
5Electrical Installation ........................................................................................................................22
5.2Wiring .............................................................................................................................................24
6Operation ...........................................................................................................................................26
6.1Differential Pressure .......................................................................................................................26
6.2Analog Outputs...............................................................................................................................28
6.3Ethernet Connection.......................................................................................................................28
6.4Analog Input ...................................................................................................................................29
6.5Display and Keys............................................................................................................................33
6.6Relay ..............................................................................................................................................42
7Maintenance ......................................................................................................................................43
7.1Service Cable .................................................................................................................................43
7.2Service Port ....................................................................................................................................43

E-M-PF4-V1_00 Rotronic AG
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7.3Device Calibration and Adjustment Procedure ...............................................................................44
7.4Validation of Analog Output Signals ...............................................................................................48
8Firmware Update...............................................................................................................................48
9Technical Data...................................................................................................................................49
10Accessories.......................................................................................................................................53
10.1Service Cable .................................................................................................................................53
10.2Pressure Tubes ..............................................................................................................................53
10.1Mounting Elements.........................................................................................................................53
11Additional Documents ......................................................................................................................54
12Document Versions...........................................................................................................................54

E-M-PF4-V1_00 Rotronic AG
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Scope:
This manual is valid for the PF4 transmitter series with firmware version V3.x. The low-order digit of the firmware
version stands for minor changes, e.g. correction of errors that do not influence the main functionality of the
device.
1 Overview
The PF4 is a high-precision differential pressure transmitter. The integrated measurement technology is able to
detect very small differential pressures. The measurement results can be shown on the built-in display and
exported via the analog outputs. Optional connection of a HygroClip2 probe, Pt100 sensor or analog input signal
is possible. The isolated change-over switch of a relay can be controlled with configurable alarms.
Main features of the PF4 transmitter:
High-precision measurement and long-term stability
Fast response time and low hysteresis
Freely configurable analog signals
Isolated integral relay switch contact
Large overload range
Optional HygroClip2 connection for humidity, temperature or analog signals
Selectable units
High immunity to dust and humidity in the environment
New firmware updates will fix newly discovered issues and add new features. The user is encouraged to stay
up to date with the newest firmware.

E-M-PF4-V1_00
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2 Dimensions
The PF4 comes as wall-mounted unit in a ROTRONIC housing. The following drawings show the relevant overall
dimensions in mm.
Figure 1: Important overall dimensions of the PF4

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3 General Description
3.1 Power Supply
The PF4 is only available as three-wire version without galvanic isolation. For configuration purposes, the device
can also be supplied with power via the service interface (Mini-USB port inside housing). During configuration
with the service interface there is insufficient power to run the differential pressure sensor to its most accurate
performance levels. The USB service connector should be used only for configuration purposes.
3.1.1 Power Supply / Current Consumption
Power supply specifications for the PF4:
Operating Voltage Current Consumption
15…40 VDC <70 mA / <150 mA (with Ethernet interface)
14…28 VAC – 50/60 Hz <70 mA / <450 mA (with Ethernet interface)

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3.2 Differential Pressure Measurement
The differential pressure measurement is based on the principle of thermal mass flow. A flow limiter in a tube
generates a differential pressure. A very small quantity of gas diverted by a bypass before and after the limiter
(max. 180 µl/min) is passed over a differential pressure sensor (∆p sensor) and then returned to the main flow.
Figure 2 on the left shows the principle of this mass flow measurement.
Figure 2:
Principle of the mass flow measurement (left) and cross-section of MEMS differential pressure sensor (right)
The ∆p sensor contains a heating element and a temperature sensor each before and after the heating element.
Due to the differential-pressure dependent flow velocity in the flow passage of the ∆p sensor, the downstream
temperature sensor heats up more or less than the upstream temperature sensor. In this way it is possible to
obtain an output voltage from the ∆p sensor as potential difference between the temperature sensor output
signals that is, following careful linearization, strictly proportional to the volume flow.
The sensor used in the PF4 series is based on a 2x2 mm silicon chip (Figure 2, right). This enables production
of an extremely small and exactly reproducible flow passage with a very high pneumatic resistance, resulting in
extremely small sensor flow rates (max. 180 µl/min) and practically independent of the bypass tube lengths and
dust and moisture loads in the gas stream.
Conclusion: The high measuring sensitivity, accuracy and long-term stability of the ROTRONIC PF4 series
make it the ideal choice for monitoring volume flows and pressures in energy-efficient and economical ventilation
and air conditioning systems.

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Inside View:
Figure 3: Inside view with description of the main components of the PF4
3.2.1 Differential Pressure Measurement Ranges
The following sensor measurement ranges are available:
-25...+25 Pa
-50…+50 Pa
-100…+100 Pa
-250…+250 Pa
-500…+500 Pa
Differential pressures outside the specified ranges are shown, but the measurement results are not reliable.
Mini-USB
service connector
Differential pressure
sensor
Terminals K3 for
isolated relay contacts
Differential pressure
tubes
HC2 sensor for
temperature and
relative humidity
Terminals K4 for analog
temp. and differential
pressure values
Terminals K2 for power
supply

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3.2.2 Unit Systems
The following unit systems are available:
Unit Unit Symbol Remarks
Pascal Pa 1 Pa = 1 N/m²
Inch water column inH2O 1 inH2O (4 °C) = 249.089 Pa
Milli-pound-force per square
inch
mpsi 1 mpsi = 0.001 psi = 6.89476 Pa
Millibar mbar 1 mbar = 0.001 bar = 100 Pa
mm mercury column mmHg 1 mmHg (0 °C) = 133.322 Pa
mm water column mmH2O 1 mmH2O (4 °C) = 9.80665 Pa
Torr Torr 1 Torr = 133.322 Pa
Gram per square centimeter g/cm21 g/cm2= 98.0665 Pa

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3.2.3 Filters
The curve of the differential pressure measured values can be smoothened with the help of a low-pass filter
with selectable time constant. There are 13 smoothing filter stages available. Practice has shown stages 0...7
meet most application requirements.
Filter Stage Time Constant 63 Time Constant 99 Description
0 0 s 0 s No filtering
1 0.4 s 1.8 s Weak filtering
2 0.9 s 4.3 s …
3 1.9 s 9.3 s …
4 3.9 s 19.3 s …
5 7.8 s 39.2 s …
6 15.8 s 78.9 s …
7 32.0 s 2.7 min. …
8 1.0 min. 5.3 min. Strong filtering
9 2.1 min. 10.6 min. …
10 4.2 min. 21.2 min. …
11 8.5 min. 42.4 min. …
12 17.0 min. 1.4 h …
13 33.9 min. 2.8 h Extremely strong filtering
3.2.4 Simulator Value
When the simulator value has been activated, a defined simulator value is used instead of the current measured
value.

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3.3 Pt100 Connection
A Pt100 temperature sensor can optionally be connected to the four-pin connector (Binder series 711). The
possible measurement range depends on the Pt100 sensor and is max. -100...200 °C.
3.3.1 Unit Systems
The following unit systems are available for temperature measurement:
°C
°F
3.3.2 Simulator Value
When the simulator value has been activated, a defined simulator value is used instead of the current measured
value.
3.4 HC2 Connection
The PF4 optionally comes with a HC2 connection socket. It can be used for all HC2 probes in the ROTRONIC
portfolio. Alternatively, one pin of the socket can be used as analog current or voltage input. It must be
established on ordering the device whether the pin can evaluate current or voltage signals; it cannot be
reconfigured to do so later on (see chapter 6.4 ).
3.4.1 Unit Systems
The following unit systems are available for the HC2 connection:
%RH
°C / °F
mV / mA

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3.4.2 Simulator Value
When the simulation value has been activated, a defined simulator value is used instead of the current measured
value.
3.5 Analog Outputs
The ROTRONIC HW4 software enables free configuration and scaling of the analog outputs. The measured
values (differential pressure, humidity, temperature, calculation value) can be assigned at will to any analog
output (Out1, Out2) and the required range can also be scaled freely.
The following output ranges are available:
Type Range
Voltage 0…1 V
0…5 V
0…10 V
Current 0…20 mA
4…20 mA
The different variants of the analog output each have a minimal offset:
Signal Type Maximum Offset at Start of Range
0...1 V 3 mV
0...5 V 50 mV
0...10 V 90 mV
0...20 mA 4 µA
4...20 mA No offset

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3.5.1 Scale
The scale can be changed at will with the ROTRONIC HW4 software in a range from -9,999 to +99,999. The
limits of the sensor must, however, be observed (see chapter 3.2 /3.3 / 3.4 ).
The devices have one of the following optional default settings on delivery:
Differential Pressure Humidity Temperature
A
nalog Input
0…+10 Pa
0…+25 Pa
0…+50 Pa
0…+100 Pa
0…+250 Pa
0…+500 Pa
-25…+25 Pa
-50…+50 Pa
-100…+100 Pa
-250…+250 Pa
-500…+500 Pa
0…100 %RH

0…50 °C
0…70 °C
+10…40 °C
0…+100 °F
0…+200 °F

0…3.2 V
0…25 mA

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3.6 Relay
The PF4 provides a freely configurable internal isolated relay contact.
Normally closed (NC)
Common (COM)
Normally open (NO)
The relay can be controlled by freely configurable alarms. The following can also be set:
Time delay
The relay is only switched on when an alarm endures for a certain minimum time.
Switch off when alarm finished
The relay automatically disengages when the alarm is no longer active; otherwise the relay remains
active until it is reset manually.
Maximum duty cycle
The relay stays on for at most the time set and is then switched off.
The relay can only be activated by a measured value. Assignment of more than one measured value is not
possible.
3.7 Service Interface
Using the HW4 software, the service interface (UART) allows device settings, loading of language data and
updating of the firmware. The service interface is located inside the housing. It is connected to the computer
with the HW4 software with an AC3006 or AC3009 connection cable.
Important:
The PF4 can be supplied with power through the service cable. The service cable provides insufficient power
for correct differential power measurement.
For sensor adjustment, the PF4 must be supplied with power from a suitable power source via the terminals
provided (K2-1: -/~, K2-2: +/~).

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3.8 Display and Keys
The optional LCD for the PF4 has a backlight.
The display unit is configurable. Depending on the version (differential pressure / differential pressure & Pt100
/ differential pressure & HC2 connection), the different parameters can be assigned to the different display lines.
In the full version with HC2 connection, there are three display lines available. They can be assigned the
following parameters:
differential pressure
humidity
temperature
analog input (is only shown when analog input is active)
calculation
no value
The first line of the display shows the differential pressure, the second the relative humidity and the third the
temperature or calculated value such as dew point / frost point. A trend indicator can also be configured for
every line.
The optional LCD for the PF4 has a backlight. The first line of the
display shows the differential pressure, the second the relative
humidity and the third the temperature or calculated value such
as dew point / frost point. The display can be configured to show
a trend indicator in every line.
Figure 4: Display of the PF4 with connected HC2 probe
Keys:
menu: Open menu / Next-higher menu level
+: Increase value
-: Decrease value
: OK / Next-lower menu level
3.8.1 Alarms
Measured values with an alarm are shown with an exclamation mark [!]. Alarms are configured with the HW4
software.

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3.8.2 Decimals
The PF4 adjusts the number of decimal places automatically on the basis of the current measured value. The
display therefore always shows the measured value clearly with the corresponding number of significant
decimals.
3.9 HW4 Software Compatibility
PF4 differential pressure transmitters are integrated completely in the HW4 software - devices with only
differential pressure measurement or additional Pt100 connector from V3.2 and later, and with HC2 connection
option from V3.4.
PF4 Version Supported in HW4 from Version:
PF4 without additional connector
PF4 with B4 connector HW4 V3.2
PF4 with E2 connector HW4 V3.4

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4 Mechanical Installation
4.1 General
The PF4 can be mounted on a wall or on a DIN top-hat rail. The position of the device and thus of the differential
pressure sensor has no influence on measurement, i.e. the device is not sensitive to position. However, for
exact measurement, the device must not move and must not be exposed to vibrations.
IMPORTANT:
After complete mechanical installation, the atmospheric pressure must be programmed in the device as
described in chapter 6.1.1.
4.2 Housing
The housing can be opened by unscrewing four screws. The screw breakthroughs for wall mounting and
electrical connections for the power supply, analog outputs, service interface and the relay are to be found inside
the housing.
Figure 5: Front view PF4 housing

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4.3 Mounting
Method 1: The PF4 comes with two screws, two wall plugs and two rubber
washers. There are two screw depressions in the bottom part of the housing
(closed on delivery). Use the template delivered with the PF4 to drill the holes
in the wall and put in the wall plugs. Place a rubber washer under each screw
head. Put a screw in each depression and push through the bottom of the
depression.
Method 2: The mounting kit AC5002 (not included) is needed for mounting on
a DIN top-hat rail (35 mm / 1 3/8"). The mounting kit consists of two clips, which
are fastened to the back of the housing with the screws supplied.
Figure 6: Mounting kit AC5002 and drilling points for wall mounting
4.4 Differential Pressure Connection
Tubes with an internal diameter of 4 mm can be connected. The tubes must be fastened securely so that
they do not move or vibrate during operation. This would falsify the measurement.
Configuration of differential pressure connections:
+: Positive pressure connection
-: Negative pressure connection
Figure 7: Differential pressure connections and E2 socket on the bottom side of the PF4

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4.5 HC2 / Analog Connection
The PF4 can optionally be ordered with an E2 socket. This interface and its possible uses are described below.
4.5.1 Use of HC2 Probe
The PF4 can optionally be set up for a HC2 probe. After connection of
a HC2 probe, it is possible to measure and display three parameters:
Differential pressure
Humidity
Temperature / Calculation
Figure 8: E2 and differential pressure connection on the bottom side
of the PF4
All HC2 probes currently available can be connected. The measured data of the HC2 probe is evaluated digitally
and shown on the display. Two of the measured values can be assigned to the analog outputs (chapter 6.2 )
and processed further. The optional Ethernet interface (chapter 6.3 ) of the PF4 can output all measured values.
4.5.2 Use of Analog Input
The device menu is used to switch between use of a HC2 probe and an analog third-party probe. The display
of the PF4 switches automatically to the units mA / mV of the analog input.
The input is reconfigured with the device menu:
MENU > Probe Information > Sensor Type
Select between the following options:
HC2 Digital HC2 probes are read out
Analog In Analog input is used
The PF4 then asks the user to confirm the sensor change and restarts with the corresponding display
configuration.
Remark:

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The PF4 does not contain a power supply for an analog third-party probe. If adequate, the power supply for the
HC2 probe can be used via the pins V+ and GND (see Figure 9).
When using an analog probe, be sure to define both the voltage signal range and the measurement range of
the probe. The HW4 software requires definition of the measurement range for an analog probe. The HW4
software can also be used to change the probe type for the input.
Pin Configuration E2 Connection
Figure 9: Pin configuration of the E2 socket (view from front)
1) V+: Digital probe: 3.3 VDC, 10 mA
2) GND: Digital and supply ground
3) RXD: UART digital probe
4) TXD: UART digital probe
5) ANA IN: Analog input: 0…3.2 V / 0…25 mA
6) NU: Not used
7) AGND: (Analog GND)