SCHUNK FMS User instructions

Translation of the original manual
Assembly and Operating Manual
FMS
Force measuring system

Imprint
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02.00 | FMS | Assembly and Operating Manual | en | 389074
Imprint
Copyright:
This manual is protected by copyright. The author is SCHUNK GmbH & Co. KG. All rights
reserved. Any reproduction, processing, distribution (making available to third parties),
translation or other usage - even excerpts - of the manual is especially prohibited and
requires our written approval.
Technical changes:
We reserve the right to make alterations for the purpose of technical improvement.
Document number: 389074
Version: 02.00|10/07/2019|en
© SCHUNK GmbH & Co. KG
All rights reserved.
Dear Customer,
thank you for trusting our products and our family-owned company, the leading
technology supplier of robots and production machines.
Our team is always available to answer any questions on this product and other solutions.
Ask us questions and challenge us. We will find a solution!
Best regards,
Your SCHUNK team
SCHUNK GmbH & Co. KG
Spann- und Greiftechnik
Bahnhofstr. 106 – 134
D-74348 Lauffen/Neckar
Tel. [phone]
Fax [phone]
[email protected]
schunk.com

Table of contents
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Table of contents
1 General.................................................................................................................... 4
1.1 About this manual ................................................................................................ 4
1.1.1 Presentation of Warning Labels ...............................................................4
1.1.2 Applicable documents ..............................................................................4
1.2 Warranty .............................................................................................................. 5
1.3 Scope of delivery .................................................................................................. 5
2 Basic safety notes ................................................................................................... 6
2.1 Intended use......................................................................................................... 6
2.2 Inappropriate use ................................................................................................. 6
2.3 Constructional changes ........................................................................................ 6
2.4 Spare parts ........................................................................................................... 6
2.5 Environmental and operating conditions ............................................................. 6
2.6 Personnel qualification......................................................................................... 7
2.7 Notes on particular risks....................................................................................... 7
3 Technical data.......................................................................................................... 8
4 Function description and application examples.......................................................10
4.1 Functional description ........................................................................................ 10
4.2 Application example........................................................................................... 12
5 Assembly ................................................................................................................13
5.1 Mechanical installation of the measuring system .............................................. 13
5.2 Electrical installation of the measuring system.................................................. 15
6 Operation ...............................................................................................................16
6.1 Preparing for commissioning.............................................................................. 16
6.2 Determining the conversion factor .................................................................... 16
6.3 Operating the force measuring system .............................................................. 17
7 Troubleshooting .....................................................................................................19
8 Maintenance and care ............................................................................................20

General
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1 General
1.1 About this manual
This manual contains important information for a safe and
appropriate use of the product.
This manual is an integral part of the product and must be kept
accessible for the personnel at all times.
Before starting work, the personnel must have read and
understood this operating manual. Prerequisite for safe working is
the observance of all safety instructions in this manual.
1.1.1 Presentation of Warning Labels
To make risks clear, the following signal words and symbols are
used for safety notes.
DANGER
Danger for persons!
Non-observance will inevitably cause irreversible injury or death.
WARNING
Dangers for persons!
Non-observance can lead to irreversible injury and even death.
CAUTION
Dangers for persons!
Non-observance can cause minor injuries.
NOTICE
Material damage!
Information about avoiding material damage.
1.1.2 Applicable documents
• General terms of business*
• Catalog data sheet of the purchased product *
• Assembly‐ and Operating Manual of the SCHUNK-module, on
which the sensor is mounted *
The documents marked with an asterisk (*) can be downloaded on
our homepage schunk.com

General
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5
1.2 Warranty
If the product is used as intended, the warranty is valid for 24
months from the ex-works delivery date under the following
conditions:
• Observe the applicable documents, Applicable documents [}4]
• Observe the ambient conditions and operating conditions,
Environmental and operating conditions [}6]
1.3 Scope of delivery
The scope of delivery includes
• Force measuring system FMS in the ordered model:
• Electronic processor FMS-A1
• Active force-measuring jaw FMS-ZBA
• Passive intermediate jaw FMS-ZBP
• Cable from the electronic processor to the force/torque sensor
system controller
Depending on the force measuring adapter used, the appropriate
electronic processor must be connected.
FMS Adapter type Electronic processor
50 FMS-A1 301 810
64 FMS-A1 301 810
80 FMS-A1 301 810
100 FMS-A1 301 810
125 FMS-A1 301 810
160 FMS-A2 301 811
200 FMS-A2 301 811
300 FMS-A2 301 811

Basic safety notes
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2 Basic safety notes
2.1 Intended use
The product is used exclusively to measure gripping forces or to
determine workpiece weights or dimensional deviations.
• The product is intended for installation in a machine/system.
The applicable guidelines must be observed and complied with.
• The product may only be used within the scope of its technical
data, Technical data [}8].
2.2 Inappropriate use
The product is not a safety component in accordance with the EC
Machine Directive 2006/42/EC and must not be used in safety-
relevant parts of machine control units.
2.3 Constructional changes
Implementation of structural changes
By conversions, changes, and reworking, e.g. additional threads,
holes, or safety devices can impair the functioning or safety of the
product or damage it.
• Structural changes should only be made with the written
approval of SCHUNK.
2.4 Spare parts
Use of unauthorized spare parts
Using unauthorized spare parts can endanger personnel and
damage the product or cause it to malfunction.
• Use only original spare parts or spares authorized by SCHUNK.
2.5 Environmental and operating conditions
Required ambient conditions and operating conditions
Incorrect ambient and operating conditions can make the product
unsafe, leading to the risk of serious injuries, considerable material
damage and/or a significant reduction to the product's life span.
• Make sure that the product is used only in the context of its
defined application parameters, Technical data [}8].
• Make sure that the environment is free from splash water and
vapors as well as from abrasion or processing dust. Exceptions
are products that are designed especially for contaminated
environments.

Basic safety notes
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2.6 Personnel qualification
Inadequate qualifications of the personnel
If the personnel working with the product is not sufficiently
qualified, the result may be serious injuries and significant
property damage.
• All work may only be performed by qualified personnel.
• Before working with the product, the personnel must have read
and understood the complete assembly and operating manual.
• Observe the national safety regulations and rules and general
safety instructions.
The following personal qualifications are necessary for the various
activities related to the product:
Trained electrician Due to their technical training, knowledge and experience, trained
electricians are able to work on electrical systems, recognize and
avoid possible dangers and know the relevant standards and
regulations.
Qualified personnel Due to its technical training, knowledge and experience, qualified
personnel is able to perform the delegated tasks, recognize and
avoid possible dangers and knows the relevant standards and
regulations.
Instructed person Instructed persons were instructed by the operator about the
delegated tasks and possible dangers due to improper behaviour.
Service personnel of
the manufacturer
Due to its technical training, knowledge and experience, service
personnel of the manufacturer is able to perform the delegated
tasks and to recognize and avoid possible dangers.
2.7 Notes on particular risks
DANGER
Danger from electric voltage!
Touching live parts may result in death.
•Switch off the power supply before any assembly, adjustment
or maintenance work and secure against being switched on
again.
•Only qualified electricians may perform electrical installations.
•Check if de-energized, ground it and hot-wire.
•Cover live parts.

Technical data
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3 Technical data
Electronic processor Designation FMS-A 1/2
Size 50 ... 125 ; 160 ... 380
Operating voltage [V]
Nominal voltage [VDC]
[Rated range]
18 - 30
24
[Reverse polarity protection]
Output signal * [V] -5 ... +5
Current input [mA] < 45
Ambient temperature [°C]
Min.
Max.
-10
+65
Accuracy ** ±3% for ID 301 810
±5% for ID 301 811
Weight [kg] 0.38
IP rating 67 with inserted plug connector
and closed cover
* The output voltage is linear to the forces occurring at the gripper
fingers. The bandwidth of the output signal is not fully used by
each active intermediate jaw.
** Before measuring, a zero adjustment must be carried out.
More technical data is included in the catalog data sheet.
Whichever is the latest version.
The force measuring jaw and the passive intermediate jaw are
always adapted to the gripper:

Technical data
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9
Behavior active (with
sensor systems)
Height
H [mm]
Measureme
nt range up
to [N]
Overload
range up to
[N]
Behavior passive
(intermediate jaw)
Height
H [mm]
FMS-ZBA → PGN-plus
50
20 145 290 FMS-ZBP → PGN-plus
50
20
FMS-ZBA → PGN-plus
64 / PZN-plus 64
22 260 520 FMS-ZBP → PGN-plus
64 / PZN-plus 64
22
FMS-ZBA → PGN-plus
80 / PZN-plus 80
24 430 860 FMS-ZBP → PGN-plus
80 / PZN-plus 80
24
FMS-ZBA → PGN-plus
100 / PZN-plus 100
28 685 1370 FMS-ZBP → PGN-plus
100 / PZN-plus 100
28
FMS-ZBA → PGN-plus
125 / PZN-plus 125
30 1120 2240 FMS-ZBP → PGN-plus
125 / PZN-plus 125
30
FMS-ZBA → PGN-plus
160 / PZN-plus 160
36 1600 3200 FMS-ZBP → PGN-plus
160 / PZN-plus 160
36
FMS-ZBA → PGN-plus
200 / PZN-plus 200
40 2325 4650 FMS-ZBP → PGN-plus
200 / PZN-plus 200
40
FMS-ZBA → PGN-plus
240 / PZN-plus 240
46 on request on request FMS-ZBP → PGN-plus
240 / PZN-plus 240
46
FMS-ZBA → PGN-plus
300 / PZN-plus 300
53 5150 10300 FMS-ZBP → PGN-plus
300 / PZN-plus 300
53
FMS-ZBA → PGN-plus
380
64 on request on request FMS-ZBP → PGN-plus
380
64
Range of measurement: range within which the total system has
an accuracy of ±3% / ±5%.
Overload range: range within which the total system has an
accuracy of > ±3% / ±5%. At the end of the overload range, there is
the danger of the mechanical destruction of the intermediate jaw.
Range of measurement and overload range apply to each
intermediate jaw.

Function description and application examples
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4 Function description and application examples
4.1 Functional description
The FMS force measuring system allows you to measure forces
that act on the base jaw in the direction of the jaw movement. The
force must act centrally on the force measuring adapter.
Depending on the application, one to three active (equipped with
sensor systems) FMS-ZBA intermediate jaws are needed. The
remaining base jaws contain the passive FMS-ZBP intermediate
jaws (without sensor systems). Alternatively, the fingers can be
manufactured accordingly.
For each active intermediate jaw FMS-ZBA, an electronic processor
FMS-A1 is required for the evaluation, as well as a connection cable
FMS-AK for connecting the electronic processor with a power supply
unit and a force/torque sensor system controller (e.g. a PLC).
The active intermediate jaw is made to be deformed specifically in
the micron range. This deformation is detected by an integrated
DMS. Furthermore, the intermediate jaw is made in such a way
that a moment or force from a different direction only slightly
changes the measured value. It is therefore generally only the
gripping forces which are measured.
By means of the force/torque sensor system controller, the DMS
small signal is amplified and output to a voltage level proportional
to the gripping force.
When this is done, a positive value indicates a force acting from
the center of the gripper on the finger (e.g., a workpiece between
the gripper fingers), while a negative value indicates an external
force on the gripper fingers (e.g. reaching into a bore hole).
The output voltage level has a linear relationship to the occurring
force. However, only a change in force will be detected and not an
absolute force.
This means that when measuring, the force/torque sensor system
controller has to be reset to zero before gripping (button on the
force/torque sensor system controller or digital signal). After that,
gripping ought to be started immediately and the output
measured value ought to be evaluated.
To convert the measured value into a force, the factor included in
the data sheet and the value of the base gradient is required.
Since the pitch m is a function of the finger length, the distance
from which the gripping takes place is inserted into the formula
which has been provided by the factory. The distance is the length
between the base jaws of the gripper and the gripping point. The
result of this calculation is the gradient factor for the
corresponding finger length.

Function description and application examples
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Example The gripping force is to be determined at a distance to the base
jaw of 75 mm using an FMS 100.
Formula from the data sheet:
m [75 mm] = Factor * distance [mm] + basic pitch
m [75 mm] = (– 0.00307 * 75 + 2.49)
m [75 mm] = 2.26
The measured value of the output voltage is:
Ua = 1100 mV
The gripping force is then calculated:
F = = = 487 N
At a distance of 75 mm and the measured output voltage, the
gripping force is: 487 N.

Function description and application examples
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4.2 Application example
Gripping force control The PLC can output the automatically measured gripping force by
control signals to the proportional valve supplying the gripper.
In this way, fragile parts can be approached with a weak force until
the fingers rest against the part. Thereafter, the force is slowly
increased until it is sufficient for a secure grip.
Teaching of robots The teaching of robots to grip firmly fixed workpieces can be done
easily and precisely.
Only when the left and right gripper jaws apply the same force
does the gripper grip symmetrically. Grippers and robots are
protected.
Static gripping force
control
• Monitoring the gripping force as the jaws close prevents the
workpiece from being dropped when movement initiates.
• Overload protection by monitoring the maximum permissible
force which can, for instance, be triggered by an unintended
increase in pressure, off-center gripping or incorrect positioning
of the workpiece.
• Preventive servicing by changing grippers in good time when
there is a decline in the gripping force. Unexpected
manufacturing down-times are avoided.
Dynamic gripping
force control
• The effect of acceleration forces on the gripper jaws can be
recorded and the motion sequence modified if necessary.
• Component monitoring during highly dynamic movements.
Measuring and
teaching processes
• Dimensional checking of the gripped component on the basis of
an inserted reference component.
• Comparing the component weight:
by measuring the weight force of the component acting on the
gripper fingers.

Assembly
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13
5 Assembly
5.1 Mechanical installation of the measuring system
NOTICE
Property damage due to incorrect bending radius!
The product may get damaged if the cable's bending radius is less
than the minimum.
•Static: 10 times the cable diameter.
•Dynamic: 15 times the cable diameter.
Dimensions of the force/torque sensor system controller FMS-A1/ A2
1 Ø4.5 ( 2x) for mounting screw M4
ØMounting the intermediate jaws on the base jaws of the
gripper.
ØFasten the gripper fingers to the intermediate jaws.
The drilling pattern of the intermediate jaws corresponds to
that of the base jaws. This way, the gripper fingers can be
mounted on the intermediate jaw as well as on the base jaw.
ØFasten the electronic processor using two M4 screws.
The distance from the electronic processor to the force
measuring jaws must not exceed the length of the cable
supplied.
NOTE
When screwing the force measuring adapter onto the gripper, and
the gripper finger to the force measuring adapter, the nominal
torque of the screws is to be observed.

Assembly
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Dimensions of the FMS-ZBA/P intermediate jaws for PGN-plus 100 and PZN-plus 100
1 Active intermediate jaws 4 Passive intermediate jaws
2 Sleeve Ø 10f7 (2x each) for
finger connection
5 for bore hole Ø10 H7
3 Sleeve Ø 10f7 (2x each) for
gripper connection
6 for bore hole Ø10 H7

Assembly
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5.2 Electrical installation of the measuring system
Connecting the force
measuring jaw to the
electronic processor
Since the cable is a direct part of the measuring body and has a
strong influence on the measuring signal, it is firmly attached to
the measuring body. Replacing or extending the cable will change
the measuring accuracy.
There must be no alternating torsion. The specified bending radii
must be observed.
With correct installation, the cable has a lifetime of > 9 million
cycles.
Connecting the
electronic processor
to a controller
The extension cable type FMS-AKx should be used for this purpose.
red dot
The device socket is of the type ODU Mini Snap, size 0, 6-pin.
Electrical interface for higher-level control unit
Wire colors in
the cable
Pin in connection
plug at the FMS-A1
Meaning of the signal
yellow 5 +24 V DC
gray 6 GND
green 4 Reset (zero adjustment of
the output signal) 24 volt
for 100 ms
brown 1 + UA (shielded) (–5 to +5
V DC)
white 2 – UA (shielded)
Shield 3 Shield

Operation
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6 Operation
6.1 Preparing for commissioning
■All points from the Installation chapter must have been carried
out carefully.
ØApply a power supply to the electronic processor.
ØCheck if the display shows a value between -5V and +5 V.
ØCheck the function by manually exerting a force on the gripper
finger with the force measuring adapter. If the measured value on
the display changes visibly, the measuring system is operational.
ØSubsequently, carry out a zero adjustment of the electronic
processor and verify that the displayed value jumps to "zero".
✔The measuring system is now ready for operation.
6.2 Determining the conversion factor
The "voltage to power" conversion factor was determined by
SCHUNK and supplied with the measuring system on a data sheet.
During installation, this value may change again slightly (for
instance depending on the tightening torque with which the
screws of the intermediate jaws and fingers were tightened).
For very precise measuring values, the measuring system must be
recalibrated. For the calibration of the measuring system, two
measured values are needed. Since the ratio of the output voltage
to the gripping force is linear, a pitch can be determined on the
basis of these two measured values which very accurately
correspond to the specific system design.
Determining the measured values:
ØOpen gripper (force-measuring jaws unloaded).
ØCarrying out a zero adjustment Functional description [}10].
ØMount a load cell (e.g. Kistler) between the gripper fingers.
ØClose the gripper.
ØRead off the gripping force at the force/torque sensor system
controller of the load cell.
ØRead the output voltage on the display of the FMS measuring system.
ØDetermine the pitch
Gripper open: 0 N = 0 V
Gripper closed: x N = y V
If no load cell is available, two different weights can also be used
to determine the conversion factor. These are attached to the
gripper finger with the measuring jaw hanging freely.
The conversion factor can be derived from the output voltage that
appears on the display.
However, the supplied conversion factor is sufficient for most
applications.

Operation
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6.3 Operating the force measuring system
The output voltage must be correctly read by the control. The
conversion factor must be programmed into the application.
The gripper can be operated as usual.
Gripping force
control:
Always set the system to zero with a zero adjustment before
gripping. The gripper is closed and the proportional valve is
adjusted in accordance with the measured value until the desired
value for the gripping force has been set.
Teaching of robots: Method 1: If the gripper is open, movement will continue until the
measuring finger touches the workpiece. Following this, the exact
center position is calculated by the robot. It is easier to equip both
gripper fingers with force measuring jaws and to approach the
workpiece from both sides.
Method 2: The gripper is equipped with two force measuring jaws.
A zero adjustment is performed with both FMS-A1/A2 units. The
clamped workpiece is gripped. Now the gripper is moved by the
robot (using the smallest possible steps) until the values of both
force measuring jaws are identical. This position is the best
gripping position.
Static gripping force
control
In the system, the zero adjustment and the gripping are carried
out and the value is compared to a set value or with previous
measured values.
If the gripping force deviates substantially from the set value in
spite of the same pressure, this indicates the aging of the gripper.
If no gripping force is present, this indicates the loss of a
workpiece.
If a measuring system has been installed on both base jaws and
the measured values of the two systems differ, the gripping was
carried out off-center (as a result, the gripper or the robot is
frequently overloaded).
Dynamic gripping
force control
The change in gripping force is monitored, thereby enabling the
detection of overload or impending loss of parts before any
damage occurs.

Operation
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Measuring and
teaching processes
Dimension check in the μm range:
A reference part is inserted as a gauge between the active jaw
near the gripper and the passive intermediate jaw. The gripper is
closed. Perform a zero adjustment with the system. The gripper
opens. The part to be measured is inserted between the fingers in
addition to the reference part. The gripper is closed with the same
force (pressure or voltage). If the dimensions of the gripped
workpiece are greater than planned, a gripping force greater than
zero will be displayed.
If the gripped workpiece is too small, a gripping force of less than
zero will be displayed. The reference part must be selected so that
while the gripper is being closed with an inserted reference part, a
dimensionally accurate workpiece is touched by the gripper fingers
with exactly 0 N.
Weight checking: The gripper grips the workpiece and the gripper is rotated so that
the measuring jaw is on top.
Perform a zero adjustment with the system. Swing the gripper
180° and read the measured value.
This value only changes depending on the weight of the
workpiece. The linearity of the output voltage to the workpiece
weight is, however, only about 15%.
Within a small range, however, a change in weight can be
determined very accurately.
If accurate measurements are to be made, it is worth determining
the conversion factor within the range of the handling weights.
If, for example, the measuring is done in the range between 10 kg
and 12 kg, the above measuring method is carried out once with
10.0 kg and once with 12.0 kg. From the two measured voltage
levels, a highly accurate conversion value can be determined for
this range.

Troubleshooting
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7 Troubleshooting
Malfunctions Possible cause Corrective action
Replace display. Voltage is missing or
its polarity is
incorrect or it is out
of the permitted
range.
Connecting the voltage correctly:
18 – 30 V (yellow = + 24 VDC; gray = 0 VDC)
The value in the
display does not
change when the
measuring jaws are
loaded
Measuring jaws not
connected to force/
torque sensor
system controller.
Insert the connection plug of the measuring
jaw in the force/torque sensor system
controller.
The measuring jaws
are not loaded in the
direction of the jaw
movement.
The system measures only forces in the
direction of the jaw movement. Only the
gripping forces are to be measured; for this
purpose, the other forces are largely hidden.
The measured value
fluctuates slightly
The air supply is not
uniform.
Ensure constant pressure.
Vibrations or
external forces are
occurring.
Hold the gripper steady.
The measured value
»flows«
Determined by the
system
When forces are constantly present, there is a
slight flow of the material particularly in the
upper part of the measurement range. This
effect can be seen in the output voltage and is
normal.
The measured value
shown on the
display differs from
the analog signal
Resolution of the
display
To optimize costs, a simple display unit is
installed. The exact value is the voltage at the
output.
The shield has not
been applied.
The shield must be connected for error-free
transmission of the measured value to the
analog input. Only in this way are the EMC
rules observed.
The analog input
card is not set
correctly.
The analog input card should have an input of
–5 V to +5 V. Set the card correctly.
Other errors Please inform SCHUNK.

Maintenance and care
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8 Maintenance and care
The force measuring system is maintenance-free.
Unless otherwise specified, secure all screws and nuts with Loctite
no. 243 and tighten with the appropriate tightening torque.
Any contact of drilling fluids with the measuring intermediate jaw
ought to be avoided.