halstrup-walcher PUC 28 User manual

______________________________________________________________
Instruction Manual PUC 28
Process monitoring device
for clean rooms
halstrup - walcher GmbH
Stegener Straße 10
D-79199 Kirchzarten
Tel.: [phone]
Fax: [phone]
E-Mail: [e-mail]
Internet: www.halstrup-walcher.com
Document 7100.004424 Version 1.0 12/2011

Instruction Manual PUC 28
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Table of Contents:
1 Validity and purpose of the instruction manual......................................................................4
2 Safety precautions.................................................................................................................5
2.1 Appropriate use................................................................................................................5
2.2 Shipping, assembly, electrical connections and start-up .................................................5
2.3 Troubleshooting, maintenance, repairs, disposal.............................................................5
2.4 Symbols ...........................................................................................................................6
3 Device description.................................................................................................................7
3.1 General functional description..........................................................................................7
3.2 Cyclic zero-point calibration.............................................................................................8
3.3 Display of measured values.............................................................................................8
3.4 Display and controls.........................................................................................................9
3.5 Manual zero-point calibration.........................................................................................10
3.6 Re-Calibration................................................................................................................10
3.7 Connections...................................................................................................................10
4 Assembly.............................................................................................................................12
5 Setting the parameters........................................................................................................13
5.1 Abbreviations used.........................................................................................................14
5.2 Basic settings [ SETTINGS ]..........................................................................................15
5.2.1 Language [ SETTINGS / LANGUAGE ]....................................................................15
5.2.2 Changing the password [ SETTINGS / NEW PASSWD ].........................................15
5.2.3 Measurement range of the internal pressure sensor [ SETTINGS / MEAS. R. ] ......15
5.2.4 External sensors (IN1 and IN2) [ SETTINGS / CONF. EXTERN ]............................16
5.2.5 Display [ SETTINGS / DISPLAY ].............................................................................16
5.2.6 Signal [ SETTINGS / SIGNAL ].................................................................................17
5.2.7 Acoustic signalling device [ SETTINGS / SOUND ]..................................................17
5.2.8 Decimal places display [ SETTINGS / DECIMAL PL. ].............................................17
5.2.9 Delete Re-Calibration [ SETTINGS / UNDO TEACH ]..............................................18
5.2.10 Reset the device [ SETTINGS / RESET ]...............................................................18
5.2.11 Recall the delivery state [ SETTINGS / DELIVERY ST. ].......................................18
5.3 Scaling and limits [ VALUES ]........................................................................................18
5.3.1 Scaling [ VALUES / SCALE ]....................................................................................19
5.3.2 Limits [ VALUES / WARNING ].................................................................................19
5.4 Filter setting [ FILTER ]..................................................................................................21
5.5 Relays [ RELAY ] ...........................................................................................................22
5.5.1 Switching conditions and relay test [ RELAY / COND. TEST ].................................22

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5.5.2 Relay activation and deactivation delays [ RELAY / TIME REL. ] ............................23
5.5.3 Alarm acknowledgement [ RELAY / ACKNOWLEDGE ] ..........................................24
5.6 Re-Calibration [ TEACH ].............................................................................................24
6 RS232 Interface ..................................................................................................................26
6.1 List of RS232 commands...............................................................................................26
6.1.1 Commands for Configuration....................................................................................26
6.1.2 Commands for reading the measured values and the status values........................29
6.1.3 Other commands ......................................................................................................30
6.2 Error codes ....................................................................................................................32
6.3 Assignment of the RS232 connector..............................................................................33
6.4 Interface configuration....................................................................................................34
6.5 Configuration software...................................................................................................34
7 Profibus DP interface ..........................................................................................................38
7.1 Profibus DP address......................................................................................................38
7.2 Terminating resistors......................................................................................................38
7.3 Modules .........................................................................................................................39
7.4 Setting the parameters of the PUC 28 as a Profibus slave............................................41
7.5 Assignment of the Profibus connector ...........................................................................42
8 Adjusting the PUC 28 [ TEACH ].........................................................................................43
8.1 Adjusting the internal pressure transmitter.....................................................................43
8.2 Adjusting the analogue inputs and outputs....................................................................44
9 Care instructions for PUC 28...............................................................................................44
10 Technical data...................................................................................................................45
11 Troubleshooting.................................................................................................................45
12 Dimension drawing............................................................................................................46
13 Menu tree..........................................................................................................................47
14 Ranges of values and default settings ..............................................................................50

Instruction Manual PUC 28
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1 Validity and purpose of the instruction manual
This instruction manual applies to the PUC 28 starting with software version 3.6.
The instruction manual explains the operation and handling of the process monitoring device.
Improper use of this device or failure to follow these instructions may cause injury to people or
equipment damage. Every person who uses this device must therefore read the manual and
understand the possible risks. The instruction manual, and in particular the safety precautions
contained therein, must be followed carefully. Contact the manufacturer if you do not
understand any part of this instruction manual.
Handle this instruction manual with care:
It must be readily available throughout the lifecycle of the device.
It must be provided to any individuals who assume responsibility for operating the
device at a later date.
It must include any supplementary materials provided by the manufacturer.
The manufacturer reserves the right to continue developing this device model without
documenting such development in each individual case. The manufacturer will be happy to
determine whether this manual is up-to-date.
Conformity
This device is state of the art. It complies with the legal requirements of EC directives. This is
shown by the CE mark.
© 2010
The manufacturer owns the copyright to this instruction manual. It contains technical data,
instructions and drawings detailing the device’s features and how to use it. It must not be
copied either wholly or in part or made available to third parties.

Instruction Manual PUC 28
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2 Safety precautions
2.1 Appropriate use
The PUC 28 is used to test pressure, temperature and humidity.
Always observe the operating requirements —particularly the permissible supply voltage —
indicated on the rating plate and in the “Technical data” section of this manual.
The device may only be handled as indicated in this manual. Modifications to the device are
prohibited. The manufacturer is not liable for damages caused by improper use or failure to
follow these instructions. Violations of this type render all warranty claims null and void.
2.2 Shipping, assembly, electrical connections and start-up
Do not close the pressure ports during shipping. Changes in barometric pressure may damage
devices with low measurement ranges.
Assembly and the electrical connections should only be handled by professionals. They should
be given proper training and be authorized by the operator of the facility.
The instrument may only be operated by appropriately trained individuals who have been
authorized by the operator of the facility.
The functional test must not be performed using compressed air or breath because otherwise
devices with low measurement ranges could be damaged.
Measurement errors may occur if the instrument is not kept protected from sunlight. Specific
safety precautions are given in individual sections of this manual.
The first step is to create a recess in the wall (approx. 232 x 132 mm) at the site of installation
using the hole template provided. See section entitled “Assembly” for additional assembly
steps.
The instrument must be grounded at the ground terminal.
2.3 Troubleshooting, maintenance, repairs, disposal
The individual responsible for the electrical connections must be notified immediately if the
device is damaged or if malfunctions occur that cannot be corrected as indicated in the section
entitled “Troubleshooting”.
This individual must take the instrument out of service until the malfunction has been corrected
and ensure that it cannot be used unintentionally.
Always unplug the power cord before opening the device!
This instrument requires no maintenance.
Only the manufacturer may perform repairs that require the housing to be opened.
The electronic components of the device contain environmentally hazardous materials and
materials that can be reused. The device must therefore be sent to a recycling plant when you
no longer wish to use it. Compliance with the environmental codes of your particular country is
mandatory.

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2.4 Symbols
This instruction manual uses the following symbols to emphasize references to the operation
and hazards when using the system:
WARNING! This warns you of a potential hazard that could lead to bodily
injury up to and including death if the corresponding instructions are not
followed.
CAUTION! This warns you of a potential hazard that could lead to significant
property damage if corresponding instructions are not followed.
INFORMATION! This indicates that the corresponding information is important
for operating the device properly.
[ ]
MENU PATH: In section 5 (entitled “Setting the parameters”), the menu
paths are shown using brackets (e.g., [ VALUES / WARNING ]).

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3 Device description
3.1 General functional description
The PUC 28 is a microprocessor-controlled process monitoring device designed for use in
clean rooms. It has one internal differential pressure sensor and two analogue inputs (0 ... 10
V and 0 (4) ... 20 mA each) for connecting external sensors. One temperature and one
humidity sensor or two additional pressure sensors may be connected to these two ports. The
signal of the internal pressure sensor can be provided by way of the OUT output as a current
or voltage value (0 ... 10 V and 0 (4) ... 20 mA). The pressure which has to be measured has
to be led to the two pressure input ports at the rear side.
The three process values (e.g., pressure, temperature and humidity) are shown on the
integrated display. At the same time, the limits, which can be set as parameters, are monitored
and an acoustic alarm is triggered if a value moves outside its limits. In addition, two relay
contacts (changeover contacts) represent these alarm states (in some variants of the PUC 28
these relay contacts are not present). These contacts may be used, for example, to drive
external signal devices (strobe light or horn) or to feed the alarm signal to a central building
control system. As an option, confirming the alarm by way of the push of a key can be set as a
parameter.
Fig. 1: Block diagram of the PUC 28
The PUC 28 can be supplied with a Profibus DP interface for connection to the central building
control system. In this case, the PUC 28 is integrated into the Profibus as a slave. It is possible
to read all values of the PUC via the Profibus or to use the PUC as a display and an evaluation
device in that the process signals (Pressure/IN 1/IN 2) are not provided by way of the internal
pressure sensor or the analogue inputs but rather via the Profibus.
The parameters of the PUC 28 are set in a menu-driven manner using the four integrated keys
(see section 5 entitled “Setting the parameters”) or using the Profibus.

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The PUC 28 has an internal overpressure safeguard that protects the precision pressure
measurement capsule from damage.
Optionally a connection of the PUC 28 via a serial RS232C interface is also possible, this
allows configuring the PUC 28 (alternatively to the configuration with the help of the integrated
keys in the front plate) as well as reading the measured values and triggering certain actions
(e.g. zero-point calibration) with the help of a PC. A PC configuration software also addresses
these functions, which might serve as a remote station to the PUC 28 with RS232 interface.
3.2 Cyclic zero-point calibration
External influences such as temperature, position or ambient pressure can shift the device's
zero point, i.e., the value displayed when the pressure ports are open. Calibration is the
process by which the device automatically registers this shift and figures it into the currently
displayed pressure. During this process, “CALIBRATION” appears in the top line of the
display. Calibration is always performed after power is applied to the PUC 28. As the PUC 28
must frequently adjust to the ambient temperature after power is applied (e.g., a new
installation), calibration is performed every 15 minutes in the following hour. After this, a cyclic
calibration is performed every hour. If the PUC 28 is in the parameter mode, calibration is
postponed until after the parameters are set.
If the PUC 28 has an RS232 or Profibus DP interface, the cyclic calibration can be replaced by
a calibration command as an alternative. This ensures that no measured values are lost during
critical process phases because of a calibration procedure.
3.3 Display of measured values
The display is capable of showing three measured values:
1st line - pressure (measured by the internal pressure sensor)
2nd line - value of the signal present at the input IN1
(dependent on the sensor connected: temperature or pressure)
3rd line - value of the signal present at the input IN2
(dependent on the sensor connected: relative humidity or pressure)
If the signal wanders outside the set limits (alarm), the corresponding line alternates between
displaying the measured value and a blinking arrow. The arrow pointing upward indicates that
the upper limit has been exceeded. An arrow pointing downward indicates that the signal has
dropped below the lower limit.
If the inputs IN1 and/or IN2 are not used, the corresponding lines can be blanked on the
display (see section 5 entitled “Setting the parameters”). The internally measured pressure can
also be blanked. In this case additionally no zero-point calibration takes place.
During the zero-point calibration procedure, the PUC 28 does not react to the press
of a key. In this case, please wait a few seconds until the end of the calibration
procedure (e.g., confirmation of an alarm).

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Fig. 2: Alternating display of the temperature and humidity showing that the values have dropped below
the limits.
3.4 Display and controls
Fig. 3: Front of the PUC 28
The process monitoring device has an LCD display that can show three measured values. The
integrated keys are used to confirm alarms and for the menu-driven setting of the parameters
for the PUC 28. Functions are dynamically assigned to the keys.
Enter
Scroll right
Scroll up
Menu
Pressure
Temperature (optional)
Humidity (optional)

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3.5 Manual zero-point calibration
Additionally to the cyclic zero-point calibration (see section 3.2 entitled “Cyclic zero-point
calibration”) the zero-point calibration can also be initiated at any time manually, as long as the
device is in display mode. To start the calibration, press “Enter”. Thereon the question
“Calibrate ?” with the selections “No” and “Yes” appears. By default, “No” is selected. Now with
the keys “Scroll up” or “Scroll right” change to “Yes” and confirm with “Enter”. Then the zero-
point calibration will be started.
3.6 Re-Calibration
The device variant PUC 28/K has an additional pair of pressure input ports available at the
front side, which can be used to re-calibrate the device if required. This function can only be
called out of the main menu, therefore it is password protected (see section 5 entitled “Setting
the parameters”). The positive range (0...100Pa resp. 0...250Pa) and the negative range
(0...-100 Pa resp. 0...-250Pa) might be re-calibrated independently from each other. In case
the positive range shall be re-calibrated, a reference pressure of +100Pa resp. +250Pa has to
be applied from outside; in case the negative range shall be re-calibrated, a reference
pressure of -100Pa resp. -250Pa has to be applied from outside.
3.7 Connections
Terminal
Connection description
Description
1
OUT I
Analogue current output (internal pressure sensor)
2
OUT -
Chassis ground for the analogue output (internal
pressure sensor)
3
OUT U
Analogue voltage output (internal pressure sensor)
4
OUT EARTH
Cable shield (internal pressure sensor)
5
IN2 I
Analogue current input (humidity or pressure)
6
IN2 U
Analogue voltage input (humidity or pressure)
7
IN2 -
Chassis ground connection for IN2
8
IN2 +
+24VDC supply for IN2
9
IN1 I
Analogue current input (temperature or pressure)
10
IN1 U
Analogue voltage input (temperature or pressure)
11
IN1 -
Chassis ground connection for IN1
12
IN1 +
+24VDC power supply for IN1
13
GND
PUC 28 chassis ground
14
VCC
PUC 28 supply voltage (+24 V DC)
Table 1: Terminal assignment, control line connector
Use the “IN1 +” and “IN1 I” or the “IN2 +” and “IN2 I” connections if hooking up a
sensor with a two-wire configuration. “IN1 +” (resp. “IN2 +”) is the supply of the
sensor; “IN1 I” (resp. “IN2 I”) is the sensing input and the minus-pole of the sensor
at the same time.
If the cable at the analog OUT connection is longer than 3 meters, a shielded
cable must be used. The shield must be connected to the OUT EARTH
connection.

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Terminal
Connection description
Description
1
EARTH
Ground connection
2
RL1_NO
Normally open contact
Relay 1
3
RL1_Common
Common
4
RL1_NC
Normally closed contact
5
RL2_NO
Normally open contact
Relay 2
6
RL2_Common
Common
7
RL2_NC
Normally closed contact
Table 2: Terminal assignment, relay connector (in some variants of the PUC 28 the relay contacts and
therefore also the relay connector are not present)
Pressure input port at rear side
(input for measurement)
Description
+P
Positive pressure
- P
Negative pressure
Pressure input port at front side
(input for re-calibration)
Description
+P
Positive pressure
- P
Negative pressure
(The input for re-calibration is only available at the device variants “PUC 28/K”.)
Table 3: Assignment of the pressure input ports

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Terminal assignment of the RS232 interface:
For the RS232 interface there are two possibilities:
9-pole D-SUB-jack (female)
(top view from outside):
5-pole M12-jack (female, A-encoded)
(top view from outside):
Fig. 4: RS232 interface (9-pole D-SUB-jack, female or 5-pole M12-jack, female)
Terminal assignment: see section 6.3 entitled “Assignment of the RS232 connector”
Terminal assignment of the Profibus DP interface:
For the Profibus DP interface there are two possibilities:
9-pole D-SUB-jack (female)
(top view from outside):
5-pole M12-jack (female, B-encoded)
(top view from outside):
Fig. 5: Profibus DP interface (9-pole D-SUB-jack, female or 5-pole M12-jack, female)
Terminal assignment: see section 7.5 entitled “Assignment of the Profibus connector”
The PUC 28 variants with 9-pole D-SUB-jack differs to that effect, that the jack is either directly
integrated in the housing or that it is located at the end of a flying leads cable which is lead out
of the housing between both terminal connectors.
PUC 28 variants with M12-jack are only available with flying leads cable.
4 Assembly
The first step is to create a recess in the wall (approx. 116 x 220 mm) at the site of installation
using the enclosed hole template and to copy the drilling template.
Afterwards all connections to the PUC 28 have to be established, then mount the PUC 28 in
the recess of the wall.

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5 Setting the parameters
Setting the PUC 28 parameters is menu-driven. The main menu is called using the “Menu”
key. This is followed by a request to enter the password. As delivered, the password is set to
“0000”. The password may be changed in the menu item “New password”. You may exit the
menu at any time using the Menu key. If no key is pressed for about 2 minutes, the PUC 28
automatically returns to the display mode. If you exit the menu and call it again within 2
minutes, the password is not requested again. In the following sections, the individual menu
items are explained in detail in the context of the menu tree (also see section 12 entitled
“Menu tree”).
The function of the keys changes depending upon the active menu item.
Key
Name
Function
Effect
Menu
Call or exit the menu for setting the parameters
Scroll up
Navigate
Selecting a submenu (moving the arrow)
Set a parameter
Increasing the number at the cursor or
changing properties
Scroll right
Navigate
Selection
Set a parameter
Scroll the cursor to the right (e.g., selection of
the number of a parameter to be changed)
Enter
Menu selection
Open the marked submenu
Set a parameter
Confirm the value of a parameter
Table 4: Functions of the keys
Example: Changing the password from 0000 to 2600
current display Key(s) Remark
In the following sections on menu description, it is assumed that the password
has already been entered and confirmed and the main menu has already been
displayed.
Call the menu to set parameters
The default setting of the password is 0000
and can now be confirmed using “Enter”
Scroll up twice to mark the submenu
[ SETTINGS ]
Open the marked “Settings”submenu using
“Enter”
PASSWORD
0000
VALUES
SETTINGS
7,2 Pa
21,8 °C
75,6 %rH
2 x

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5.1 Abbreviations used
In showing the menu on the display, the following abbreviations are used:
Table 5: Menu abbreviations used in the display
German
English
Description
D
P
Pressure
1
1
Input “IN1”
1-T
1-T
Input “IN1” used for measuring temperature
1-D
1-P
Input “IN1” used for measuring pressure
2
2
Input “IN2”
2-F
2-H
Input “IN2” used for measuring humidity
2-D
2-P
Input “IN2” used for measuring pressure
OUT-D
OUT-P
Pressure output signal
HYST
HYST
Hysteresis
U
U
Voltage signal 0 ... 10 V
I-0
I-0
Current signal 0 ... 20 mA
I-4
I-4
Current signal 4 ... 20 mA
2 x
6 x
Scroll once up to mark the next submenu
item [ SETTINGS / NEW PASSWD ]
Open the “New password”submenu item
using “Enter”
Increase the number to 2 by scrolling up
twice
Move to the next digit by scrolling right
Increase the number to 6 by scrolling up six
times
Confirm using “Enter”
Exit setting parameters using “Menu”and
return to display mode
Caution: The new password is now needed
to call the menu!
LANGUAGE
NEW PASSWD
NEW PASSWD
0000
NEW PASSWD
2000
NEW PASSWD
2000
6 x
NEW PASSWD
2600
NEW PASSWD
7,2 Pa
21,8 °C
75,6 %rH

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5.2 Basic settings [ SETTINGS ]
This menu branch contains the basic settings of the PUC 28.
5.2.1 Language [ SETTINGS / LANGUAGE ]
This submenu is used to select the display language.
Parameter
description
Range of
values
Default setting
Language
D - German
GB - English
German
Table 6: Display language choices
5.2.2 Changing the password [ SETTINGS / NEW PASSWD ]
This submenu is used to change the password for enabling the parameter menu.
Parameter
description
Range of
values
Default setting
Password
Consists of 4
digits
0000 ... 9999
0000
Table 7: Password parameter
5.2.3 Measurement range of the internal pressure sensor [ SETTINGS / MEAS. RANGE ]
This parameter can specify the measurement range of the internal pressure sensor. The
parameter is a function of the installed pressure sensor and is already set at the factory.
Table 8: Measurement range parameter
Parameter
description
Range of values
Default setting
Measurement
range
100 Pa
250 Pa
A function of the installed sensor
Setting the measurement range affects scaling, the limits and the characteristic
curve of the internal pressure sensor. For this reason, the default setting should
not normally be changed.

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5.2.4 External sensors (IN1 and IN2) [ SETTINGS / CONF. EXTERN ]
External sensors may be connected to the inputs IN1 and IN2. The parameter informs the
PUC 28 as to which sensor is connected to the corresponding input.
Parameter
description
Range of values
Default settings
External
sensors
IN1 –Temperature; IN2 –Humidity
IN1 –Temperature; IN2 –Pressure
IN1 –Pressure; IN2 –Humidity
IN1 –Pressure; IN2 –Pressure
IN1 –Temperature
IN2 –Humidity
Table 9: Possible settings for the external sensors
The units of the values shown in the display are adjusted automatically (temperature in °C,
humidity in %rH, pressure in Pa). The units of a pressure display can be subsequently
changed to hPa or mbar in the following “Display” submenu.
5.2.5 Display [ SETTINGS / DISPLAY ]
In the default setting, the display shows three values:
Pressure
Temperature
Humidity
There are three submenus for these parameters. The display of each individual value can be
blanked in these submenus (blanking of the entire line). This makes sense if no sensor is
connected to the corresponding input or the internal pressure sensor is not used. If the value
represents a pressure, the units can be selected (Pa, hPa or mbar). The range of values for
the corresponding channel depends on the setting in the menu branch “CONF. EXTERN” that
was used to specify which sensor is connected to the corresponding input.
Channel *
Parameter description
Range of values
Default setting
INT. PRESS.
IN1-P
IN2-P
Units of pressure for the
display of the internal or
externally connected
sensors
Pa
hPa
mbar
OFF - no display
Pa
IN1-T
IN2-H
Whether the display is
blanked or not
ON
OFF
ON
Table 10: Display settings
* The channels are displayed according to the selection made under “CONF. EXTERN”.

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5.2.6 Signal [ SETTINGS / SIGNAL ]
This submenu is used to specify the type for the analogue pressure output signal and the
analogue input signals IN1 and IN2 to the connected sensor.
Table
11: Display settings
5.2.7 Acoustic signalling device [ SETTINGS / SOUND ]
The internal acoustic signalling device generates, in the event of alarm, an intermittent signal
and a brief signal every time a key press is registered. The alarm signal can be confirmed by
pressing any key (even if the parameter “Alarm acknowledgement” in the relay menu is not
set). The pulse duration and separation of the intermittent alarm signal are set using the
“LENGTH” parameter. The set length also determines the alternating interval between
showing the alarm and the measured values on the display (in the case of measured values
that have gone outside their limits, see section 3.3 entitled “Display of measured values”). The
internal acoustic signalling device can be activated or deactivated.
Submenu
Parameter description
Range of values
Default setting
ON or OFF
Activation or deactivation,
respectively, of the
acoustic signalling device
ON - activated
OFF - deactivated
ON
LENGTH
Pulse duration and pulse
separation
0.1 ... 5 s
0.5 s
Table 12: Parameter description for the acoustic signalling device
5.2.8 Decimal places display [ SETTINGS / DECIMAL PL. ]
It can be specified separately for the internally measured pressure and the two inputs IN1 and
IN2 whether the measured value should be shown on the display with or without a decimal
place.
Parameters
Range of values
Werkseinstellung
INT. PRESS.
ON - Shown with decimal places
OFF - Shown without decimal places
ON
IN1-T
IN1-P
IN2-H
IN2-P
Table 13: Decimal places display parameter description
Input/output
Parameter description
Range of values
Default setting
OUT-P
Signal type (current signal
or voltage signal)
U 0 ... 10 V
I-0 0 ... 20 mA
I-4 4 ... 20 mA
I-4
IN-1
IN-2
If the units of mbar or hPa have been set for a pressure value, this value can
only be displayed with a decimal place.

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18
5.2.9 Delete Re-Calibration [ SETTINGS / UNDO TEACH ]
Any re-calibration (positive as well as negative range) carried out after the delivery will be
called off (concerns only the variants PUC 28/K).
5.2.10 Reset the device [ SETTINGS / RESET ]
The PUC 28 will be resetted completely (this is equvalent switching off and on again the power
supply of the device). The Profibus interface (for devices with Profibus DP interface) is also
initialized. The menu settings stay unchanged.
5.2.11 Recall the delivery state [ SETTINGS / DELIVERY ST. ]
According the acual configured measurement range (±100 Pa or ±250 Pa) all menu settings
are reset to the delivery state and being saved. Subsequently the PUC 28 will be resetted
completely (this is equvalent switching off and on again the power supply of the device). The
Profibus interface (for devices with Profibus DP interface) will also be initialized.
5.3 Scaling and limits [ VALUES ]
The PUC 28 is adjusted for the sensors used and the limits set for the alarm signals in the
“VALUES” menu.
Resetting the device might for example be useful if a new address is being set with
the help of the both rotary switches. After the reset the new address is active.

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5.3.1 Scaling [ VALUES / SCALE ]
The measurement ranges of the connected sensors are set for the PUC 28 in this menu
branch. “VALUE BOT” represents the measured value at 0(4) mA or 0 V. For “VALUE TOP”,
the measured value for the analogue signal (20 mA or 10 V) must be entered.
The output signal can be adjusted in the same manner for the pressure measured using the
internal sensor.
Input / sensor
Value
Range of values
Default setting
OUT-P
VALUE TOP
-120 ... +120 Pa *
-300 ... +300 Pa **
+100 Pa * / +250 Pa **
VALUE BOT
-120 ... +120 Pa *
-300 ... +300 Pa **
-100 Pa * / -250 Pa **
IN 1-T
VALUE TOP
-800 ... +800 °C
60 °C
VALUE BOT
-800 ... +800 °C
5 °C
IN 1-P
VALUE TOP
-300 ... +300 Pa
+100 Pa * / +250 Pa **
VALUE BOT
-300 ... +300 Pa
-100 Pa * / -250 Pa **
IN 2-H
VALUE TOP
0 ... 800 %rH
75 %rH
VALUE BOT
0 ... 800 %rH
0 %rH
IN 2-P
VALUE TOP
-300 ... +300 Pa
+100 Pa * / +250 Pa **
VALUE BOT
-300 ... +300 Pa
-100 Pa * / -250 Pa **
Table 14: Scaling parameter description
* Value applies to a PUC 28 with an internal ±100 Pa sensor
** Value applies to a PUC 28 with an internal ±250 Pa sensor
5.3.2 Limits [ VALUES / WARNING ]
The PUC 28 monitors the measured values and can trigger an alarm if the limit is dropped
below or exceeded. The upper and lower limits and hysteresis can be set for each measured
value in this menu branch. The hysteresis is identical for both limits and ensures that, in the
case of measured values fluctuating around the limit, an alarm is not triggered again and again
(see Fig. 13).
Please make sure that the VALUE TOP is larger than the VALUE BOT. If both
new values are positive, the upper value must be set first. If both new values are
negative, the lower value must be set first (always assuming that the old values
have been according the delivery state). In case it is tried to enter a value for the
upper value which is equal or lower than the actual lower value, the entered
value is set to the actual lower value, increased by 0.1 Pa (°C, %rH). In case it is
tried to enter a value for the lower value which is equal or higher than the actual
upper value, the entered value is set to the actual upper value, decreased by 0.1
Pa (°C, %rH). The calculated value will then be shown in the display for further
editing, the value won’t be stored yet.

Instruction Manual PUC 28
20
Fig. 13: Switching points of the relay considering hysteresis
Example: With an upper limit of 100 and a hysteresis of 10, the alarm is triggered at 105 and
reset again at 95.
Input / sensor
Value
Range of values
Default setting
Internal pressure
VALUE TOP
-120 ... +120 Pa *
-300 ... +300 Pa **
+100 Pa * / +250 Pa **
VALUE BOT
-120 ... +120 Pa *
-300 ... +300 Pa **
-100 Pa * / -250 Pa **
HYST
0 ... 50 Pa
0 Pa
IN 1-T
VALUE TOP
-800 ... +800 °C
60 °C
VALUE BOT
-800 ... +800 °C
5 °C
HYST
0 ... 100 °C
0 °C
IN 1-P
VALUE TOP
-300 ... +300 Pa
+100 Pa * / +250 Pa **
VALUE BOT
-300 ... +300 Pa
-100 Pa * / -250 Pa **
HYST
0 ... 125 Pa
0 Pa
IN 2-H
VALUE TOP
0 ... 800 %rH
75 %rH
VALUE BOT
0 ... 800 %rH
0 %rH
HYST
0 ... 50 %rH
0 %rH
IN 2-P
VALUE TOP
-300 ... +300 Pa
+100 Pa * / +250 Pa **
VALUE BOT
-300 ... +300 Pa
-100 Pa * / -250 Pa **
HYST
0 ... 125 Pa
0 Pa
Table 15: Limits parameter description
* Value applies to a PUC 28 with an internal ±100 Pa sensor
** Value applies to a PUC 28 with an internal ±250 Pa sensor
Please make sure that the VALUE TOP is larger than the VALUE BOT. If both
new values are positive, the upper value must be set first. If both new values are
negative, the lower value must be set first (always assuming that the old values
have been according the delivery state). In case it is tried to enter a value for the
upper value which is equal or lower than the actual lower value, the entered
value is set to the actual lower value, increased by 0.1 Pa (°C, %rH). In case it is
tried to enter a value for the lower value which is equal or higher than the actual
upper value, the entered value is set to the actual upper value, decreased by 0.1
Pa (°C, %rH). The calculated value will then be shown in the display for further
editing, the value won’t be stored yet.