HBM PW20i User manual

A1269-2.0 en/de/fr
Digital load cell
Digitale Wägezelle
Pesons numérique
PW20i
Mounting instructions
Montageanleitung
Notice de montage

English Seite 3 − 25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Deutsch Page 26 − 48. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Français Page 49 − 70. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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PW20i
HBMA1269-2.0 en/de/fr
Contents
Safety instructions 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 Application 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Special features 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 Identificationand variants 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 Mechanical construction and mounting hints 8. . . . . . . . . . . . . . . . . . . .
4.1 PW20i design 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2 Before start-up 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3 Mounting instructions 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 Electrical configuration and function 10. . . . . . . . . . . . . . . . . . . . . . . . . .
5.1 Function 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2 Signal processing 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.3 Trigger function 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.4 Limit value functions 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.5 Extreme value functions 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.6 Dosing and filling control 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.7 Diagnostic function 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6 Electrical connection 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.1 PW20i connection assignments 15. . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2 Supply voltage 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7 Interfaces 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.1 RS-232 / RS-485 4-wire interfaces (UART) 18. . . . . . . . . . . . . . . . . .
7.2 CANopen interface 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.3 DeviceNet interface 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.4 Digital control input 23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8 Specifications 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4PW20i
HBM A1269-2.0 en/de/fr
Safety instructions
The device must not be modified from the design or safety engineering point of
view except with our express agreement. Any modification shall exclude all
liability on our part for any damage resulting therefrom.
Repair is specifically forbidden. Repairs must only be carried out by HBM.
All the factory settings are stored at the factory so that they are safe from
power failure and cannot be deleted or overwritten. They can be reset at any
time by using the command TDD0.
The production number set at the factory cannot be changed.
•PW20i-Load cells are exclusively designed for weighing technology
measurement tasks and directly associated control and regulatory tasks.
Use for any purpose other than the above is deemed to be inappropriate.
•There are not normally any hazards associated with this product, provided
the notes and instructions for project planning, assembly, appropriate
operation and maintenance are observed.
•It is essential to comply with the safety and accident prevention regulations
specific to the particular application.
•Installation and start-up must only be carried out by suitably qualified
personnel.
•During installation and when connecting the cables, take action to prevent
electrostatic discharge as this may damage the electronics.
•The required power supply is an extra-low voltage (12 − 30 V) with safe
disconnection from the mains.
•When connecting additional devices, comply with the appropriate safety
requirements.
•Shielded cables must be used for all connections. The screen must be
connected extensively to ground on both sides.
Further information can be found in the help file on the 1-FIT-AED-DOC
(System-CD).

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PW20i
HBMA1269-2.0 en/de/fr
Residual risks are indicated in these mounting instructions by the following
symbols:
Symbol: CAUTION
Meaning: Possible dangerous situation
Warns of a potentially dangerous situation in which failure to comply with
safety requirements could result in damage to property or some form of
physical injury.
Symbols for operating instructions and useful information:
Symbol: NOTE
Means that important information about the product or its handling is being
given.
Symbol:
Meaning: CE mark
The CE mark enables the manufacturer to guarantee that the product complies
with the requirements of the relevant EC directives (the declaration of
conformity is available at http://www.hbm.com/HBMdoc).
Symbol:
Meaning: Statutory marking requirements for waste disposal
National and local regulations regarding the protection of the environment and
recycling of raw materials require old equipment to be separated from regular
domestic waste for disposal.
For more detailed information on disposal, please contact the local authorities
or the dealer from whom you purchased the product.

6PW20i
HBM A1269-2.0 en/de/fr
1 Application
The PW20i load cells belong to the digital load cells and measurement chain
family specially developed by HBM for high-speed dynamic weighing
processes. They acquire measurement signals from strain gages, condition
them digitally, output them and can network them for buses on request.
They supply a fully-filtered, scaled and digitalized output signal for direct
connection to a bus system or a PC. They operate with high sampling rates of
up to 1200 measurements per second and can be easily and rapidly adapted
to the actual weighing system by means of adjustable parameters.
The integrated trigger function allows event-driven weight determination which
significantly reduces the external software requirements for checkweigher
applications, for example.
The PW20i includes dosing control. As this load cell does not have any digital
outputs, the external Master control must make digital I/Os available. The
PW20i generates the information to control these digital outputs in the
respective measurement statuses (MSV - measurement status). The Master
control then only needs to forward these control bits to its digital outputs, in
order to drive the dosing control valves.
The load cell can be delivered with RS-485, RS-232, CANopen or DeviceNet
interface options.
PW20i load cells are space-saving in use and are protected against spray
water and contamination by a stainless steel casing (IP 65).
The PC software AED_Panel32 is available to facilitate parameter settings, to
display dynamic measurement signals and for comprehensive frequency
analysis of the dynamic system.
This part of the operating instructions describes the hardware and the functions
of the PW20i digital load cells. In the help file “AED_help_e” you will find the
commands for serial communication.

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2 Special features
•high overload limits
•integrated overload stop
•high-speed digital filtering and scaling of the measurement signal
•serial interfaces: RS-232 or RS-485-4-wire,CANopen, DeviceNet
•all settings made via the serial interface
•power fail safe parameter storage
•indestructible storage of factory defaults
•choice of output speed for the measured values of up to 1200 values/s
•limit value functions
•extreme value functions (MIN/MAX)
•trigger functions (internal level triggering, external triggering)
•dosing control
•diagnostic functions (bus)
•Operating voltage 12 V ... 30 VDC
•degree of protection: IP 65
3 Identification and variants
The PW20i can be supplied in four different interface types. The accuracy
class is C3 (OIML).
Max. capacity: 5, 10, 20
Accuracy class: 3 = C3
Interface: A=RS-232, B=RS-485, C=CANopen, D=DeviveNet
Product family PW20i (3rd Generation)
Fig. 3.1 PW20i ordering designation, Explanations: RS-485 = RS-485 4 wire bus
The following preferred types are defined (other variants on request):
Interface
RS-232 RS-485 (4-wire) CANopen-bus DeviceNet
1-PW20i/3A3/xxKG 1-PW20i/3B3/xxKG 1-PW20i/3C3/xxKG 1-PW20i/3D3/xxKG

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HBM A1269-2.0 en/de/fr
4 Mechanical construction and mounting hints
4.1 PW20i design
Digital PW20i load cells are characterized by a compact aluminum-
measuring body and are designed with IP 65 protection. The electronics are
integrated in the measuring body.
19
19
118
65 33
M6
7,5
M6
33
15
10
63
10
15
30
7
66
31,5
Fig. 4.1 PW20i dimensions (in mm; 1 mm = 0.03937 inches)
4.2 Before start-up
The following precautionary measures must be complied with during
mounting and operation:
•The length of the fastening screws must be selected so that the maximum
screw-in length of 10 mm is not exceeded. Non-compliance can cause
damage to the load cell.
•The integrated overload protection acts in positive and negative load
directions. Please note the permissible maximum values for eccentric loads
and take into account overloads from knocks.
•Avoid force shunts during setup.

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PW20i
HBMA1269-2.0 en/de/fr
4.3 Mounting instructions
A_6
Base plate
Recommended
flatness: 0,1
Platform centre
Loading direction
Platform
Load application
(Design by customer)
PW20i
(1)
(2)
1: Connection of PW20i to loading application: 2 x M6; strength class 10.9;
max. screw-in depth 10 mm; tightening torque 10 N⋅m.
Recommended flatness 0.1 mm at the connection surface
2: Connection of PW20i with base plate: 2 x M6; strength class 10.9;
tightening torque 10 N⋅m; max. screw-in depth 10 mm
Load cell centre
Fig. 4.2 PW20i mounting instructions
The PW20i load cell must be mounted on a clean surface with a flatness of
t0.1 mm. An overload protection in the tensile and compressive directions
protects the load cell from overload.
It is recommended that the load is applied in the center of the load cell to
minimize corner load errors and moments.
The following must be noted when installing several PW20i in a system with a
bus system:
The printed production number (identification plate) is required for setting up
the data communication. If the identification plate can no longer be seen after
installation, the numbers of all PW20i should be noted beforehand. This
enables address assignment during the initial start-up.
Alternatively, before connection to the serial bus, each PW20i can be
individually connected to a PC in order to set different addresses(see
ADR-command, help file).

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5 Electrical configuration and function
The electronics of the digital PW20i load cell basically comprises the following
function groups:
•Single point load cell
•Amplifier
•Analog/digital converter (A/D)
•Evaluation unit (µP)
•Power failsafe parameter storage (EEPROM)
•Serial interface
•Control input (trigger/stop dosing)
5.1 Function
Fig.5.1 Block diagram
The analog transducer signal is first amplified, then filtered and converted to a
digital value in the analog/digital converter. The digitized signal is conditioned
in the microprocessor and forwarded via the serial interface. All the parameters
can be stored power failsafe in the EEPROM.
The PW20i load cell is adjusted at the factory with zero load and maximum
capacity. The electronics determine a factory characteristic curve from these
measured values and use this characteristic curve to map the subsequent
measured values. Depending on the output format (COF), the following
measured values are returned:

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PW20i
HBMA1269-2.0 en/de/fr
Output format Input signal Measured values where
NOV = 0 Meas. val- ues where
NOV > 0
Binary 2 chars. (integer) 0 ... max. capacity 0 ... 20,000 Digit 0 ... NOV
Binary 4 chars. (long integer) 0 ... max. capacity 0 ... 5 120 000 Digit 0 ... NOV
ASCII 0 ... max. capacity 0 ... 1 000 000 Digit1) 0 ... NOV
1) Delivery condition
The two parameters LDW und LWT give you the opportunity to adapt the
characteristic curve to meet your requirements (scale characteristic curve) and
you can use the NOV command to standardize the measured values to the
required scaling value (e.g. 3000 d). Detailed information can be found in the
help file.
5.2 Signal processing
Fig. 5.2 Signal flow diagram
After amplification and A/D conversion, the signal is filtered by adjustable
digital filters.
The commands ASF and FMD are used to set the cut-off frequency of the
digital filters. The command ICR is used to change the output rate (measured
values per second).
The user can set their own characteristic curve (commands LDW, LWT and
NOV) without changing the working standard calibration. Gross/net selection is
also available (TAS command). Command ZSE activates an automatic zero on
start-up function. An automatic zero tracking function (ZTR) is also available.
A command (LIC) is available for linearization of the scale characteristic curve
(with a third order polynomial). The polynomial parameters can be set using
the HBM PC program, AED_Panel32.

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HBM A1269-2.0 en/de/fr
The current measured value is read out using the command MSV?. The format
of the measured value (ASCII or binary) is set with the command COF. You
can also use command COF to select automatic data output.
Different types of digital filter are implemented in the PW20i and these are
selected using the FMD command. With FMD0, filters are also available below
the 1 Hz cut-off frequency. In filter mode FMD1, fast-settling filters with high
damping in the stop band are activated. Detailed information can be found in
the help file (”Individual command descriptions”).
5.3 Trigger function
The PW20i includes four trigger functions to support measurements in
packaging machinery and checkweighers:
•Internal pre-triggering via an adjustable level
•External triggering via the digital control input TRG (pre-trigger)
•Internal post-triggering via an adjustable level
•External triggering via the digital control input TRG (post-trigger)
Gross or net values can be processed as measured values (TAS).
The trigger function is described in the help file, Trigger function overview.

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PW20i
HBMA1269-2.0 en/de/fr
5.4 Limit value functions
Four limit values are available in the PW20i, which are set via the LIV
command. The status of the limit value functions can be read from the
measurement status (MSV? or RIO?). You can choose between the gross
value, the net value, the trigger result or the MIN/MAX extreme values as the
input signal for limit value monitoring. The input mode has to be set to IMD0/1.
As this load cell does not have any digital outputs, the external Master control
must make digital I/Os available. The PW20i generates the information to
control these digital outputs in the respective measurement statuses
(MSV-measurement status, RIO). The Master control then only needs to
forward these control bits to its digital outputs, in order to drive the limit switch
outputs.
For more detailed information, please see the help file, Limit value function.
5.5 Extreme value functions
The PW20i includes an extreme value function that can monitor either gross or
net measured values. Output of the two extreme values (MIN and MAX) is
implemented by the PVA command. The CPV command can be used at any
time to clear the extreme values. The command PVS is used for activation.
For more detailed information, please see the help file, Extreme value function.
5.6 Dosing and filling control
The PW20i includes dosing control. As this load cell does not have any digital
outputs, the external Master control must make digital I/Os available. The
PW20i generates the information to control these digital outputs in the
respective measurement statuses (MSV − measurement status, RIO). The
Master control then only needs to forward these control bits to its digital
outputs, in order to drive the dosing control valves.
The PW20i contains 32 parameter sets that are held in the EEPROM. The
RDP command is used to select them. Dosing parameters can be changed
while dosing is ongoing.
The filling and dosing function is activated via the command IMD2;.
In this case, the settings of the limit value function and the trigger function have
no significance.
The dosing function can be found in the help file; Commands for dosing
control.

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HBM A1269-2.0 en/de/fr
5.7 Diagnostic function
A diagnostic function has been built into the PW20i to monitor dynamic
measurement. This function includes a memory for 512 (binary) measured
values and associated status information. Different recording modes are
available so that the processes can be analyzed without interrupting
measurement.
The advantage of this diagnostic function is that the measured values are
stored in real time (without loss of data) and then read out slowly (OFF-line).
This means that it is possible to access this real-time data even at low
communication rates.
The diagnostic function is accessed via the serial interface (UART with
RS-232/RS-485, CANbus or DeviceNet = main channel of communication).
There is no separate hardware interface implemented for this.
The diagnostic function is described in the help file, description of the
commands for diagnosis with the PW20i.

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PW20i
HBMA1269-2.0 en/de/fr
6 Electrical connection
6.1 PW20i connection assignments
ATTENTION
The PW20i can be operated with a supply voltage of up to 30 V. Incorrect
connections between the power and interface lines can cause irreversible
damage.
Check the correct assignment of the connections before switching on for
the first time.
Any HBM guarantee is rendered invalid for damage caused by incorrect
connections.
Socket Pancon, 8-pin
Cable length
3 m
Fig.6.1 Connecting cable
RS-232 interface
Terminal / color code RS-232
1 red Voltage +12...30 V
2 white Ground GND
3 blue Transmitter TxD
4 green −− −−
5 black −− −−
6 gray Receiver RxD
7 yellow Control input TRG
8 unassigned −− −−

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HBM A1269-2.0 en/de/fr
CANopen and DeviceNet interface
Terminal / color code CANopen /
DeviceNet
1 red Voltage +12...30 V
2 white Ground GND
3 blue CAN_Bus_Out CAN_H_Out
4 green CAN_Bus_In CAN_H_IN
5 black CAN_Bus_Out CAN_L_Out
6 gray CAN_Bus_Out CAN_H_Out
7 yellow Control input TRG
8 unassigned −− −−
RS-485 interface
Terminal / color code RS-485
1 red Voltage +12...30 V
2 white Ground GND
3 blue Transmitter TA
4 green Receiver RA
5 black Transmitter TB
6 gray Receiver RB
7 yellow Control input TRG
8 unassigned −− −−
NOTE:
•The PW20i-load cell enclosure is connected to the cable shield. To obtain
an EMC-compliant connection (EMC = electromagnetic compatibility), the
shield at the cable end must be connected to the enclosure of the connected
device or the earth potential. The shield must be connected directly and with
low impedance (e.g. with EMC-compliant PG bushings).
•Use shielded, low-capacitance cables only for all connections (interfaces,
power supply and additional devices) − (the HBM measurement cables
meet these requirements).
•Electrical and magnetic fields often induce interference voltages in the
measurement electronics. Do not route the measurement cables parallel to
power lines and control circuits. If this is not possible, protect the
measurement cable (with steel conduit for example). Avoid stray fields from
transformers, motors and contact switches.
•Should it be necessary, a separate cable can be used to establish potential
equalization between the PW20i and the (PC/PLC) master (earthing
concept). Cable shielding must not be used for this potential equalization.

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PW20i
HBMA1269-2.0 en/de/fr
6.2 Supply voltage
Regulated dc voltage of +12 ... +30 V is required to operate the measurement
electronics and serial communication.
Voltage source requirements:
•The supply voltage must be sufficiently smoothed (rms value less residual
ripple > 12 V).
•The PW20i electronics have a low loss regulator that consumes 1.5 W
during operation. The power consumption is therefore dependent on the
level of the supply voltage:
][
1.5
][ VVoltage
W
A
Power Requ. =
•When switched on, the electronics briefly consume a current of approx.
0.15 A. To ensure a safe start-up, the power supply must be able to provide
this current without a limit being triggered. It is particularly important when
supplying several PW20i load cells from one power supply unit. In contrast,
the continuous loading is calculated from the equation shown above.
•Connection to a wide-ranging supply network is not permitted as this often
causes interfering voltage peaks to be coupled into the transducer. Instead,
a local power supply must be provided for the PW20i load cells (even when
grouped).
•The supply voltage must be insulated from the shield potential. A connection
from GND to the enclosure is not necessary, but the maximum potential
difference can only be 10 V. Should it be necessary, a separate cable can
be used to establish potential equalization between the PW20i and the
(PC/PLC) master (earthing concept). Cable shielding must not be used for
this potential equalization.
•The power supply ground wire (GND) is also used as the reference potential
for the interface signals and the control input.
•In layouts with several transducers, the power supply can be installed
together with the RS-485 bus lines in a 6 pin cable (e.g. with HBM junction
boxes). Ensure that there is sufficient wire cross-section provided as some
cable sections will conduct the supply current for all the connected PW20i
load cells.

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HBM A1269-2.0 en/de/fr
7 Interfaces
ATTENTION
The PW20i interface driver relates to GND. The Master interface driver
must also relate to this GND.
A shielded cable must be used as the bus cable. The shield should
always be connected to the housing at both ends. The shield of the
PW20i cable is electrically connected to the measuring body.
Should it be necessary, a separate cable can be used to establish
potential equalization between the PW20i and the (PC/PLC) master
(earthing concept). Cable shielding must not be used for this potential
equalization.
7.1 RS-232 / RS-485 4-wire interfaces (UART)
The PW20i load cells are delivered as required, either with an RS-232- or
RS-485 4-wire interface. Baud rates of 1200 – 115200 Baud can be set for
both interfaces. The ground reference for all interface signals is based on the
power supply ground (GND) of the PW20i load cell.
The RS-232-interface is only suitable for a point to point connection (one
PW20i load cell to one interface). Only the signals RxD ( Receive Data ), TxD
( Transmit Data ) and GND1 are required.
TxD TxD For communication with an external device
RxD RxD the TxD line must be connected to the RxD of the PW20i
GND GND and vice−versa.
Fig.7.1 Schematic connection of the RS-232 interface
Figure 7.2 shows the necessary connections (RS-232 version) for connecting
to a computer.
12...30 V
Fig. 7.2 Connection of one PW20i to the supply voltage and a computer via an
RS-232 interface

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PW20i
HBMA1269-2.0 en/de/fr
Multi-channel measurements are possible with a bus configuration using
PW20i load cells with an RS485 interface. All transducers on a line are
switched in parallel and are differentiated by the software assigning different
addresses. When the control computer has an RS232 interface, an interface
converter is required (e.g. HBM SC232/422B). The correct assignment of the
transmit and receive lines can be seen in Figure 7.3 (Bus line Ra to Ta of the
converter, etc.). The HBM converter and the PW20i both already contain bus
termination resistors. So no additional bus termination resistors are required.
Up to 32 PW20i can be connected to one bus.
The following must be noted when installing several PW20i’s in a system with
an RS-485 bus system:
The printed production number (identification plate) is required for setting up
data communication. If the identification plate can no longer be seen after
installation, the numbers of all PW20is should be noted beforehand. This
enables address assignment during the initial start-up.
Alternatively, before connection to the RS-485 line, each PW20i can be
individually connected to a PC in order to set different addresses (see
ADR-command, help file).
Fig. 7.3 Connecting several PW20i load cells to a computer via a 4-wire RS-485 bus
Wiring for the RS-485 version is similar, with lines RA, RB, TA, TB, GND and UB.
ATTENTION
The PW20i interface driver relates to GND. The Master interface driver
must also relate to this GND.
The PW20i already includes bus termination resistors. So no additional
bus termination resistors are required.

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HBM A1269-2.0 en/de/fr
A shielded cable must be used as the bus cable. The shield should
always be connected to the housing at both ends. The shield of the
PW20i cable is electrically connected with the PW20i housing (see Pin
assignments, PW20i).
7.2 CANopen interface
The interface is set up using the CANopen standard CiA DS301.
Bus configuration
The CAN bus is configured as a 2-wire circuit (CanH and CanL) (see
ISO11898). It is essential for bus termination resistors (each 120 W) to be
connected at the start and end of the bus. The PW20i does not contain a
bus termination resistor. The structure of the bus wiring was chosen to
minimize the length of the spur lines.
Fig. 7.4 CANBus bus wiring
ATTENTION
The PW20i CANbus driver relates to GND. The Master CANbus driver
must also relate to this GND.
A shielded cable must be used as the bus cable. The shield should
always be connected to the housing at both ends. The shield of the
PW20i cable is electrically connected with the PW20i housing (see Pin
assignments, PW20i).
Baud rate and bus cable lengths
The table below gives the maximum cable lengths for the CANopen bus,
subject to the baud rate:
Baud rate [kBit/s] 10 20 50 125 250 500 800 1000
Max. cable length [m] 5000 2500 1000 500 250 100 50 25