edc PR 550 User manual

EN
Page 1 PR 550 Rev1.0 Jul20
INSTRUCTION MANUAL
PR 550
The dew point sensor PR 550 with 3-wire technology 4…20 mA and RS 485
Modbus output enables a reliable and long-term stable monitoring of the dew point in
industrial applications such as in
- compressed air plants (refrigerating/adsorption dryers)
- granulate dryers
- medical gases
- non-corrosive gases, e. g. nitrogen

Table of Content
Page 2 PR 550 Rev1.0 Jul20
Table of Content
1Foreword ............................................................................................................................3
2Pictograms and Symbols....................................................................................................4
3Signal words according ISO 3864 and ANSI Z 535..........................................................4
4Intended use........................................................................................................................5
5Device description..............................................................................................................6
6Safety Instructions..............................................................................................................7
7Technical data ....................................................................................................................8
7.1 Signal circuits..............................................................................................................9
7.1.1 Modbus.................................................................................................................9
7.1.2 Current output ......................................................................................................9
7.1.3 Alarm....................................................................................................................9
8Dimension ........................................................................................................................10
9Electrical Wiring ..............................................................................................................11
9.1 Cable glands - clamping ranges.................................................................................11
9.2 Connector pin assignment .........................................................................................11
** The Current outputs, X5 and X6, are optional.(Active and passive version
available)..........................................................................................................................12
9.3 Wire connection.........................................................................................................13
9.3.1 General:..............................................................................................................13
9.3.2 Power supply......................................................................................................13
9.3.3 Modbus RTU..................................................................................................... 13
9.3.4 Modbus TCP (Ethernet) Optional PoE............................................................... 14
9.3.5 Pulse Output.......................................................................................................14
10 Installation........................................................................................................................15
10.1 Installing directly into the process.........................................................................15
11 Modbus.............................................................................................................................17
11.1 Register Mapping measuring values...................................................................... 17
Remark for RD400 / RD500 / Handheld devices - Modbus Sensor Datatype:....................17
“Data Type R4-32“ match with “Data Type Float“ ............................................................ 17
11.2 Modbus Settings (2001…2006)............................................................................ 18
11.3 Analog Scaling Settings (2007…2011) ...............................................................18
12 Operation..........................................................................................................................19
12.1 Initialization...........................................................................................................20
12.2 Main menu.............................................................................................................20
12.3 Settings...................................................................................................................21
12.3.1 Sensor Settings...................................................................................................22
12.3.2 Definition of Reference- and System pressure...................................................23
12.3.3 Modbus RTU Setup............................................................................................26
12.3.4 Modbus TCP (Optional).....................................................................................27
12.3.5 Alarm..................................................................................................................30
12.3.6 User Setup. .........................................................................................................31
12.3.7 4 -20mA.............................................................................................................. 32
12.3.8 PR 550 Info ........................................................................................................34
13 Calibration / Adjustment..................................................................................................35
14 Warranty...........................................................................................................................35
15 Ordering details................................................................................................................36

Foreword
Page 3 PR 550 Rev1.0 Jul20
1 Foreword
Dear Customer,
Thank you for choosing the PR 550. Please read these installation and operating instructions
carefully before installation and commissioning and follow our instructions. The proper
functioning of the PR 550 and safe operation can only be ensured if the regulations and
instructions described are strictly observed.

Pictogram / Symbols
Page 4 PR 550 Rev1.0 Jul20
2 Pictograms and Symbols
General Warning symbol (Danger, Warning, Caution)
General note
Installation- and Instruction manual to consider (on Nameplate)
Installation- and Instruction manual to consider
3 Signal words according ISO 3864 and ANSI Z 535
Danger!
Imminent danger
As a consequence of incorrect handling: serious personal injury or death
Warning!
Possible hazard
As a consequence of incorrect handling: possible serious injury or death
Caution!
Imminent hazard
As a consequence of incorrect handling: possible personal injury or damage
Note!
Possible hazard
As a consequence of incorrect handling: possible personal injury or damage
Important!
Additional notes, information, tips
As a consequence of incorrect handling: Disadvantages in operation and
maintenance, no danger

Intended Use
Page 5 PR 550 Rev1.0 Jul20
4 Intended use
The PR 550 dew point sensor is intended for measuring the dew point or the pressure dew
point in clean, dry and oil-free gases and compressed air.
It is the responsibility of the user whether the instrument is suitable for the selected
application. It must be ensured that the medium is compatible with the wetted parts. The
technical data listed in the data sheet are binding.
Improper handling or operation outside the technical specifications is not permitted. Claims of
any kind based on improper use are excluded.

Intended Use
Page 6 PR 550 Rev1.0 Jul20
5 Device description
The PR 550 dew point sensor enables a reliable and long-term stable monitoring of the dew
point in industrial applications.
When mounting PR 550 into compressed air systems the pressure dew point (dew point
under pressure) up to 50 bar (in the special version up to 500 bar) is measured directly.
When mounting PR 550 in atmospheric conditions (ambient pressure) or in the flow off sector
(relaxed air) of compressed air systems the atmospheric dew point is measured.
Typical Application
•compressed air plants (membrane- /adsorption dryers)
•Residual moisture measurement / dew point measurement in gases such as:
Oxygen, nitrogen, argon, hydrogen, natural gas, biogas …
Advantages:
•Extremely long-term stable
•IP 67 housing grants a reliable protection in extreme industrial conditions
•Very fast response time
•Installable in the dryer by means of G 1/2" thread, optional UNF 5/8“
•Analog output
o1x 4..20mA (galv. not isolated)
•Modbus RTU Interface
•Optional
o2x 4..20mA galv. isolated
oEthernet or Ethernet PoE
oMBus
•Calibration on location and testing with the control and calibration set (PC connection
set)
PC Instruments Service Software
With the PC Service Software incl. USB / Modbus Adapter the Modbus settings, the scaling of the
Analogue output and the assignment of the measurement values could be set.
- Analogue output 4…20 mA scalable
- Switching between °Ctd, °Ftd, % RH, °C, °F, g/m³, mg/m³, g/kg, ppm, and so on
- Calibration and adjustment
- Sensor diagnosis
- Read-out of service data

Safety Instructions
Page 7 PR 550 Rev1.0 Jul20
6 Safety Instructions
Read these operating instructions carefully before installing the PR 550.
Failure to observe the instructions contained herein, in particular the safety
instructions, may result in hazards to personnel, equipment and systems.
•The product may only be used in accordance with its intended purpose.
•Installation of the dew point sensor and maintenance work may only be carried
out by trained personnel.
•Installation and service work must be carried out in a de-energized state.
•The applicable safety regulations must be observed!
•All work on the compressed air network must only be carried out in a
depressurized state.
•Attention: Do not exceed the pressure range > 50 bar for the standard version.
•Observe the measuring ranges of the sensor!
Overheating will destroy the sensors.
•Observe the permissible storage and transport temperature as well as the
permissible operating temperature (e.g. protect the measuring instrument from
direct sunlight).
•Opening the instrument, improper handling or use of force will void all warranty
claims!
•Important: Before installation, briefly allow compressed air to flow off to remove
condensate and particles, this will prevent soiling of the PR 550.
•Standing air leads to long measuring times.

Technical data
Page 8 PR 550 Rev1.0 Jul20
7 Technical data
Measuring range -80…20 °Ctd pressure dew point resp. dew point in °Ctd
0…100 % RH
-20…70 °C
Accuracy: typical
1 °Ctd von 50…-20 °Ctd
2 °Ctd von -50…-20 °Ctd
3 °Ctd von -50…-80 °Ctd
Pressure range: -1…50 bar standard
Power supply: 24V VDC (10..30 VDC)
Outputs: 4…20 mA galv. not isolated, **
Optional: 2x 4.20mA galv. isolated
RS 485 (Modbus RTU) **
Optional: Ethernet, Ethernet PoE, MBus
Protection class: IP 67
EMV: DIN EN 61326
Operating temperature: -20…70 °C (ideal 0…50 °C)
Storage temperature: -40…80 °C
Load for analogue output: < 500 Ohm
Screw-in thread: G 1/2" stainless steel
Optional: UNF 5/8”
Material of housing: Aluminium die cast
Sensor protection: sinter filter 50 m stainless steel
Connection: M12, 5-pole
Display: 2“ TFT Colour Display (320 x 240)
Alarm relay max. 60V, 0,5A (AC* / DC)
NC relay, relays is closed in case of alarm and power failure.
Alarm value adjustable via keyboard. See Chapter Operation.
* Peak AC
**Note: Parallel use of both outputs (4...20mA and RS 485 Modbus) is possible.

Technical data
Page 9 PR 550 Rev1.0 Jul20
7.1 Signal circuits
7.1.1 Modbus
•According Standard EIA/TIA-485
7.1.2 Current output
7.1.2.1 Active
•Galvanically isolated
•4 … 20 mA
•RL< 500 Ohm
7.1.2.2 Passive
•Galvanically isolated
•4 … 20 mA
•RL< 500 Ohm
•Vin 12-36Vdc
7.1.3 Alarm
•Galvanically isolated (dry contact)
•Max. 48Vdc, 500mA

Dimensions
Page 10 PR 550 Rev1.0 Jul20
8 Dimension

Electrical wiring
Page 11 PR 550 Rev1.0 Jul20
9 Electrical Wiring
9.1 Cable glands - clamping ranges
For ensuring the tightness and strain relief, connector cables with the following diameters must be used.
DT570 Standard clamping range : Ø5-9mm
DT570 Ex clamping range: Ø5-10mm
9.2 Connector pin assignment
Alarm
12
I (4-20mA)
X1 X2 X3
12
GND
VB+
1 2 3
Mod(A)
1 2 3 4
NC
Main Board
Mod(B)
X4
NC
Alarm
Standard version with 1x analogue output (not galvanically isolated)
Alarm
12
I (4-20mA)
12
X1 X2 X4
X6
X5
I (4-20mA)
12
GND
VB+
1 2 3
Mod(A)
1 2 3 4
NC
Main Board
Mod(B)
Option Board 4-20mA
NC
Alarm
Version with option board 2x analogue outputs galvanically isolated
21
X1 X2 X4
K1
MBUS
12
GND
VB+
1 2 3
Mod(A)
1 2 3 4
Alarm
NC
Main Board
Mod(B)
Option Board MBus
I ( 4...20mA)
X3
NC
Alarm
Version with option board MBus

Electrical wiring
Page 12 PR 550 Rev1.0 Jul20
Connector
Pin
Signal description
X1
Power
supply
1
VB - (GND)
2
VB+ (12V –36 Vdc)
X2
Modbus
1
Modbus (B)
2
Modbus shield
3
Modbus (A)
X3
urrent output
1
I- Active
2
I+ Active
X4
Direction / Pulse
1
Alarm *
2
Alarm *
3
NC
4
NC
X5
Current output
1
1
I- Active**
2
I+ Active **
X6
Current output
2
1
I- Active **
2
I+ Active **
K1
MBus
1
MBus
2
MBus
* Outputs are galvanically isolated.
** The Current outputs, X5 and X6, are optional. (Active and passive version available).

Electrical wiring
Page 13 PR 550 Rev1.0 Jul20
9.3 Wire connection
9.3.1 General:
•Wiring to be done in strainless state only.
•Length of cable skinning to be minimized
•Not used cable entries must be closed with end caps
•Use of cables with cross section of >= 0.25mm²
9.3.2 Power supply
Alarm
X1 X2
X4
12
GND
VB+
1 2 3
Mod(A)
1 2 3 4
Âlarm
NC
Main Board
Mod(B)
12
I (4...20mA)
X3
NC
9.3.3 Modbus RTU
If the sensor placed at the end of the Modbus system a termination is required.
Therefore the enclosed 120R resistor is to be connected at Pin 1 and Pin 3 of connector “X2“
Alarm
X1 X2
X4
12
GND
VB+
1 2 3
Mod(A)
1 2 3 4
Alarm
NC
Main Board
Mod(B)
120R
12
I (4...20mA)
X3
NC

Electrical wiring
Page 14 PR 550 Rev1.0 Jul20
9.3.4 Modbus TCP (Ethernet) Optional PoE
M12 x-coded
Data LINES: 1,2 und 3,4
PoE LINES: 5,6 und 7,8
2
81
3
5 4
6
7
M12 x 1
Connection cable: Cat 6.
*PoE: Power over Ethernet
9.3.5 Pulse Output
Pulse
X1 X2
X4
12
GND
VB+
1 2 3
Mod(A)
1 2 3 4
Pulse
DIR
Main Board
Mod(B)
Potentialfreier
Schaltkontakt
Max. 48Vdc , 500mA
12
I (4...20mA)
X3
Remark: The sensor must be connected only in strain less state.

Installation
Page 15 PR 550 Rev1.0 Jul20
10 Installation
•Installation, electrical installation, commissioning, operation and maintenance of the device
must only be carried by qualified personnel, which were authorized by the plant operator.
The personnel must read the operating instructions and understand and follow their
instructions.
•If carrying out welding work on the pipeline the grounding of the welding unit is not allowed to
be done over the PR 550 itself.
•The installer must ensure that the PR 550 is connected according to the electrical
connection diagrams properly.
•The existing/ applicable national regulations governing opening and repair of the device must
be applied.
•The device fulfills the general safety requirements in accordance with EN 61010-1,
the EMC requirements of IEC / EN 61326 and NAMUR recommendation NE 43.
10.1 Installing directly into the process
If installing directly in the process must be done in the depressurized
state of the line, e.g. by using a stop valve should at both sides of the
installation point.
This makes it easy to remove the transmitter for maintenance and
calibration.
Insert the probe into the process and screw it as tight as possible by
hand. If there is a sealing ring, check the correct centering and tighten
the screw connection with a torque of 25-30 Nm.
It is not permitted to use a sealing ring with a NPT 1/2“ thread.
Appropriate PTFE sealing tape or sealant should be used instead.
!

Installation
Page 16 PR 550 Rev1.0 Jul20
Please note: It is recommended the indirect installation with measuring chamber
Advantage: Easy mounting and dismounting of the probe without interruption of the line.
Quick response time due to quick coupling. Optimum sensor protection.
Indirectly in the compressed air system
Connect probe with measuring chamber to the
compressed air pipe by means of a quick coupling. In
case of compressed air containing oil and dirt
particles a pre-filter should be installed in front of the
measuring chamber. Compressed air flows
continuously (at 7 bar approx. 1 l/min expanded) in
the capillary pipe of the measuring chamber. The
reaction times for the humidity reading are shorter
than in case of a direct mounting.
Directly in the compressed air system
Screw in probe with G 1/2" thread pressure-tight in
the center or at the top of the compressed air pipe.
Take care that measurement is effected close to the
compressed air flow. U-bend pipes or non-flowing
compressed air, result in very slow reaction times for
the moisture reading.
Measurable gases
In general, humidity can be measured in all non-
corrosive gases. In case of measurements in
corrosive gases please consult manufacturer.
PR 550
Measuring chamber
compressed air pipe
PR 550
Standard connection

Modbus
Page 17 PR 550 Rev1.0 Jul20
11 Modbus Register
The dew point sensor PR 550 comes with a Modbus RTU Interface.
Before commissioning of the sensor, the communication parameters
Modbus ID, Baud rate, Parity und Stop bit
must be set in order to ensure the communication with the Modbus master.
The adjustment can be done either with the EDC service software, RD 400, RD 500 and the
hand-held instrument IP 500 done.
Modbus communication default values:
•Modbus ID : 1 (1 -247)
•Baudrate: 19200 bps (1200,2400, 4800, 9600, 19200, 38400 bps)
•Parity: even (none, even, odd)
•Stoppbit: 1 (1,2)
Supported are following function codes:
•Function code 03: Read Holding Register
•Function code 16: Write multiple Register
For parameter settings/- changing see chapter 12 Operation/Modbus Settings
11.1 Register Mapping measuring values
Modbus
Register
Modbus
Address
No.of
Byte
Data
Type
Description
Default
Setting
Read
Write
Unit /Comment
1001
1000
4
Float
Temperature
R
[°C]
1003
1002
4
Float
Temperature
R
[°F]
1005
1004
4
Float
Relative Humidity
R
[%]
1007
1006
4
Float
Dew Point
R
[°Ctd]
1009
1008
4
Float
Dew Point
R
[°Ftd]
1011
1010
4
Float
Absolute Humidity
R
[g/m³]
1013
1012
4
Float
Absolute Humidity
R
[mg/m³]
1015
1014
4
Float
Humidity Grade
R
[g/kg]
1017
1016
4
Float
Vapor Ratio (Volume)
R
[ppm]
1019
1018
4
Float
Saturation vapor pressure
R
[hPa]
1021
1020
4
Float
Partial Vapor Pressure
R
[hPa]
1023
1022
4
Float
Atmospheric DewPoint
R
[°Ctd]
1025
1024
4
Float
Atmospheric DewPoint
R
[°Ftd]
Remark for RD400 / RD500 / Handheld devices - Modbus Sensor Datatype:
“Data Type R4-32“ match with “Data Type Float“

Modbus
Page 18 PR 550 Rev1.0 Jul20
11.2 Modbus Settings (2001…2006)
Modbus
Register
Modbus
Address
No.of
Byte
Data Type
Description
Default
Setting
Read Write
Unit /Comment
2001
2000
2
UInt16
Modbus ID
1
R/W
Modbus ID 1…247
2002
2001
2
UInt16
Baudrate
4
R/W
0 = 1200
1 = 2400
2 = 4800
3 = 9600
4 = 19200
5 = 38400
2003
2002
2
UInt16
Parity
1
R/W
0 = none
1 = even
2 = odd
2004
2003
2
UInt16
Number of Stopbits
R/W
0 = 1 Stop Bit
1 = 2 Stop Bit
2005
2004
2
UInt16
Word Order
0xABCD
R/W
0xABCD = Big Endian
0xCDAB = Middle Endian
2006
2005
2
UInt16
Modbus Enabled
FA500: 1
FA510: 1
FA515: 0
R/W
0 = Modbus disabled
1 = Modbus Enabled
11.3 Analog Scaling Settings (2007…2011)
Modbus
Register
Modbus
Address
No.of
Byte
Data Type
Description
Default
Setting
Read Write
Unit /Comment
2007
2006
4
UInt32
Output Value
4
R/W
0 = 4-20mA disabled
1 = Temperature [°C]
2 = Temperature [°F]
3 = relative Humidity [%]
4 = DewPoint [°C]
5 = DewPoint [°F]
6 = Absolute Humidity [g/m3]
7 = Absolute Humidity [mg/m3]
8 = Humidity Grade [g/kg]
9 = Vapor Ratio [ppm]
10 = Saturation VaporPressure[hPa]
11 = Partial Vapor Pressure [hPa]
12 = Atmospheric DewPoint [°C]
13 = Atmospheric DewPoint [°F]
2009
2008
4
float
4mA Scale Low
-80
R/W
2011
2010
4
float
20mA Scale High
20
R/W
Modbus installation, Modbus settings and further information refer to the manual
"Modbus Installation and Operating Instructions PR 5xx sensors"

Operation
Page 19 PR 550 Rev1.0 Jul20
12 Operation
The PR 550 is operated by means of 2 optical buttons, the operation of which takes place directly via /
through the glass cover. Thus, the PR 550 can be operated from the outside without opening the lid.
OK
OK
Optical buttons
The selection of the individual menu items is done by pressing the ">" button and confirming by
pressing "OK"
For all fields with white, information or changes can be made, selection for input is indicated by yellow
background color.
Words in green are mainly referring to the illustration(s) in the chapter section. But also
important menu paths or menu items related to it are marked in green font.
The menu navigation is generally in green font!
The table of contents and the chapter references in blue contain links to the respective chapter
headings.

Operation
Page 20 PR 550 Rev1.0 Jul20
12.1 Initialization
12.2 Main menu
Page-No.
SW Version Modbus ID
Switching to pages 2-3 or back by pressing key ““
After switching on the PR 550, the initialized screen
is displayed followed by the main menu.
Page 1
Display value is the pressure dew point, here in
°Ctd. (When measured under pressure)
The pressure dew point is always based on the
pressure in the compressed air pipe.
Page 2
Value 1: Temperature in °C
Value 2: relative humidity in %
Value 3: vapour humidity in g/m³
Page 3
Value 1: Absolute humidity in g/kg **
Value 2: Parts per Million **
Value 3: Atmospheric dew point (when the
reference pressure is set to atmospheric
pressure 1013,25 hPa) or reference dew
point based on the reference pressure
setting.
** For the calculation, the input of the system
pressure is mandatory. For entering see
chapter, see 8.3.2.