ALTHEN SG-IP-12E 4P Series User manual

Single Channel Strain Gauge Amplifier
for up to 4 parallel normalized sensors
SG-IP-12E/24E-xxx-4P
German | Switzerland | Austria
Althen GmbH Mess- & Sensortechnik
Tel: + 49 (0)619 - 70060
[email protected]
Benelux
Althen bv Sensors & Controls
Tel: [phone]
[email protected]
France
Althen / DB Innovation
Tél : [phone]
[email protected]
Sweden
Althen Sensors & Control AB
Tel. [phone]
[email protected]
USA | Canada
Altheris Inc Sensors & Controls Inc.
Tel: [phone]
[email protected]
Other Countries
please contact us
by email at
[email protected]
www.althen.de
V2.1 eng

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Content
1 General Information .................................................................................................................................3
1.1 Safety Instructions ............................................................................................................................3
1.2 Qualified Personnel ..........................................................................................................................3
1.3 Intended Use ......................................................................................................................................3
2 Instructions for use of the measuring amplifier ............................................................................ 4
2.1 Instructions for use of strain gauge sensors .........................................................................
3 Technical description ..............................................................................................................................
4 Terminal assignment .............................................................................................................................. 6
4.1 Supply voltage .................................................................................................................................. 6
4.1.1 Galvanic isolation ........................................................................................................................... 7
4.2 Strain gauge excitation voltage .................................................................................................. 7
4.3 Analogue output .............................................................................................................................. 8
4.3.1 Analogue output voltage ........................................................................................................... 8
4.3.2 Analogue output current ........................................................................................................... 8
4.4 Setpoints (option GW).................................................................................................................... 9
4.4.1 Setpoint settings ........................................................................................................................... 9
 Starting up ............................................................................................................................................... 10
 .1 Zero point adjustment range ..................................................................................................... 11
 .1.1 Tare ................................................................................................................................................... 12
 .2.1 Correction of the analogue current output ........................................................................ 14
 .2.2 Calculation of amplification determing resistor ............................................................... 14
6 Maintenance ............................................................................................................................................. 1
7 Old appliances disposal.................................................................................................................... 1
Appendix ........................................................................................................................................................ 16
Datasheet ................................................................................................................................................. 16
Order designation .................................................................................................................................. 16
Component diagram ............................................................................................................................. 17
Housing dimensions ............................................................................................................................ 18

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1 General Information
To ensure reliable and safe operation, the measuring amplifier must be operated in compliance with the
specifications according to this technical description only. These regulations must also be observed if
accessories, that have been ordered from Althen Mess- & Sensortechnik GmbH together with the
measuring amplifier being used.
Notice: Every person who is in charge for the start-up or service of this measuring amplifier must have
read this technical manual and must have understood the safety instructions in particular.
1.1 Safet Instructions
When using the amplifier, the legal- and safety regulations for each case of application must be observed.
To avoid risks for the system or the operator the following points are to be considered.
■ If any visual damage or malfunctions are noticed, the measuring system must be switched off
and marked appropriately.
■ Disconnect the supply voltage before opening the device.
■ The complete measuring unit must be protected against contact and influence of unauthorized
persons.
■ In the case of a safety-relevant application, where a potential malfunction could cause damage
to property or persons, it is imperative that an additional, independent monitor is provided.
■ In combination with sensors, the maximum loads / pressures etc. must never be exceeded.
If you have reasons to assume that safe operation is no longer possible, immediately take the device out
of operation and secure it against unintentional operation.
1.2 Qualified Personnel
This measuring system must be operated by qualified personnel and in compliance with the relevant
technical specifications only. Qualified personnel include such persons who are conversant with the
setting up, mounting and starting up of the measuring system and who have qualifications that are
appropriate for the tasks they're about to perform.
1.3 Intended Use
Amplifiers from Althen Mess- & Sensortechnik GmbH serve to measure the intended measurand and the
evaluation thereof in combination with one or more sensors. Any other use over and above that is
regarded as non-intended use.

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2 Instructions for use of the measuring amplifier
Notice: The parameterizations, further information concerning the scaling as well as the customized
analogue output can be found on the additional sheet "Device-Configuration".
Since this amplifier is a highly sensitive measurement technology product, it must be used for its intended
use as well as the described operating conditions only. Initial start-up and changes in setup and settings
must be done by qualified personnel only. To prevent interventions / modifications made by unauthorized
personnel, suitable measures must be taken. Both function and calibration must be checked regularly.
The amplifier must be operated with a separate power source used for measurement devices only. Shielded
cables, preferably twisted in pairs should be used only. The EMC-installation instructions must be complied
with.
The amplifier is contained in an aluminum housing which is equipped with an EMC- cover gasket as well
as EMC-cable glands. After initial start-up the lid is to be closed properly. Unused cable glands must be
closed with filler plugs.
The amplifier must be connected to clean earth-potential. Please refer to the EMC-Mounting-Instructions
in order to connect the sensor-shields correctly. To avoid possible potential equalization currents over the
shield of the cable to the following evaluation unit, this shield should be connected over a suitable capacitor
(10 nF / 200 V).
Overall the shield connections must be done properly to EMC-standards (as short as possible with large
wire cross-section) and connected to a central point (star grounding). In order to not increase the
disturbance sensitivity of the amplifier, all cables should be kept as short as possible and should not be
extended. Possible cable-bound disturbances (i.e. noise) must be blocked very near the cable ends
(evaluation unit) by suitable measures.
If it is to be expected that the amplifier is, as example, cleaned with a high-pressure cleaner/ steam jet an
additional protection shall be provided.
Notice: Changes of the amplifier of any kind demands for the explicit approval of Althen Mess- &
Sensortechnik GmbH. Changes of any kind done without that approval exclude all possible warranty
and/or liability of Althen Mess- & Sensortechnik GmbH.

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2.1 Instructions for use of strain gauge sensors
Notice: Strain gauge sensors with a small range are extremely sensitive to improper handling. Force
transducers can be destroyed simply by touching. Same applies for the diaphragms of pressure transducers.
So, bear in mind: handle with care!
Loading the transducer in excess of the nominal range may result in an increased and lasting zero balance
offset as well as damage to the sensor. The same applies to short-term force or pressure impulses that
exceed the nominal range.
To most force transducers the force must be applied centrically in order to avoid shear forces, that may be
harmful to the sensor, or may cause measurement inaccuracy. Centric force transmission can be ensured
by rounded surfaces, joint heads or other suitable guides.
Tightening torques while mounting any sensors may result in an increased zero balance offset.
If the sensor has been replaced, the calibration of the amplifier must be checked. A new adjustment might
be necessary.
3 Technical description
The described single channel measuring amplifier serves to supply one to 4 parallel connected strain
gauge sensors with each a resistance of 300 Ohms or more and the amplification of the sensor signals.
The supply voltage of the amplifier is galvanically isolated from analogue output, sensor supply and sensor
signal.
The circuitry is in 4-wire technology. Standard analogue outputs are available for further evaluation. The
amplifier is built in a robust aluminum die cast housing, which is suited for rough and industrial
environment.
The coarse amplification is determined by an internal resistor and can be fine adjusted by a potentiometer.
After opening the lid, the potentiometer mentioned before as well as the potentiometer for zero-
adjustment allow a correction of the calibration. In addition, a dip-switch allows to change the width of the
zero-adjustment range. If even this expansion of the range should not be sufficient, an internal resistor
can be soldered in to add a tare.
In addition the amplifier allows, in combination with option “2G”, the monitoring of the signal with 2 freely
adjustable and potential-free relays.

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4 Terminal assignment
The electrical connections are made via cable glands to terminal blocks inside. The terminal numbering can
be found on the pcb. The maximum cable cross-section is 2, mm². The EMC-installation instruction must
be complied with.
Notice: The amplifier must be operated with closed lid only.
Clamp Description Clamp Description
1
Supply Voltage
14
-
SG
-
Signal Transducer 2
2 Supply Ground 1 +SG-Excitation Transducer 2
3 Supply Ground 16 -SG-Excitation Transducer 2
Galvanic isolation
17
Screen/Enclosure
4 Analogue Ground 18 +SG-Signal Transducer 3
Analogue output 1 (0 … +10 V, ±10 V)
19
-
SG
-
Signal Transducer 3
6 Analogue output 2 (Version 4 … 20 mA) 20 +SG-Excitation Transducer 3
7 Analogue Ground 21 -SG-Excitation Transducer 3
8
+SG
-
Signal Transducer 1
22
Screen/Enclosure
9 -SG-Signal Transducer 1 23 +SG-Signal Transducer 4
10
+SG
-
Excitation Transducer 1
24
-
SG
-
Signal Transducer 4
11 -SG-Excitation Transducer 1 2 +SG-Excitation Transducer 4
12
Screen/Enclosure
26
-
SG
-
Excitation Transducer 4
13 +SG-Signal Transducer 2 27 Screen/Enclosure
Option -2G-:
28
SP 1 (Relay 1) (30 VDC / 0. A) MIN N/C
31
SP 2 (Relay 2) (30 VDC /
0. A) MAX N/C
29
SP 1 (Relay 1) (30 VDC / 0. A) MIN root
32
SP 2 (Relay 2) (30 VDC / 0. A) MAX root
30
SP 1 (Relay 1) (30 VDC / 0. A) MIN N/O
33
SP 2 (Relay 2) (30 VDC / 0. A) MAX N/O
Terminals “supply ground” and “analogue ground” are isolated galvanically. To unset this isolation clamp 2
(3) and 4 are to be bridged.
4.1 Suppl voltage
The supply voltage is with version -24E in the range of 18 to 30 VDC and with version –E12 within 10 to
18 VDC. The presence of the supply/ internal operating voltage is indicated by the 2 green LEDs on the
pcb, in case of option -GW (Grenzwerte=Setpoints) on the case-lid.
To protect the electronics an (to the supply voltage version corresponding) internal self-healing
“polyswitch-resettable®” fuse is built in. Whether an external additional fuse is necessary is to be checked.
However, an additional external fuse of 0, A is recommended.
If the indicator LEDs go off, the supply voltage and possibly existing external protection has to be checked.
Notice: During switch-on phase the amplifier is capacitive. Thus, the switch-on current is greater than the
operating current. This must be taken into consideration when dimensioning and selecting the power pack,
especially if several amplifiers are being wired to the same power source.

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4.1.1 Galvanic isolation
The supply voltage of the amplifier is galvanically isolated from analogue output, sensor supply and sensor
signal. To unset this isolation, clamp 2(3) and 4 have to be bridged.
4.2 Strain gauge excitation voltage
The transducer can be supplied with either 10 VDC or VDC unipolar voltage. This value can be selected
with solder points (LP-04 and LP-0 ) for coarse, and with potentiometers (P-03 and P-04) for fine
adjustment.
If an optional pre-adjustment of the amplifier has been ordered, the excitation voltage is pre-selected
and fine adjusted. Changing the excitation voltage should not be necessary.
Fig. 1: Soldering points for excitation voltage adjustment
LP-0 A LP-0 B LP-04A LP-04B Excitation voltage
ON OFF ON OFF ± V (10 VDC)
OFF ON OFF ON ±2, VDC ( VDC)

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4.3 Analogue output
The following standardized analogue outputs, depending on the ordered option, are available:
Version …010:
The output is: 0 … +10 Volts (max 1 mA)
Version …B10:
The output is: ± 10 Volts (max 1 mA)
Version …420:
The output is: 4 … 20 mA (max 00 ohms)
Other analogue outputs available on request. For parameter settings, further information concerning
scaling, or customized analogue outputs, please refer to the additional sheet “Allocation / Device
Configuration).
4.3.1 Analogue output voltage
The analogue voltage output can be picked up on the corresponding clamps. See chapter 4 “Terminal
Assignment”.
In combination with a transducer which is capable to handle tension and compression forces an analogue
output of ± 10 volts is available. But if a unipolar voltage is needed it is possible to set the zero point of
the transducer to volts of the output. This zero-point elevation is also necessary for the analogue
current output. ( V ± V equals 12 mA ± 8 mA) To lift the zero point to V, please refer to chapter .1.1
“tare”.
4.3.2 Analogue output current
The analogue current output can be picked up on the corresponding clamps. See chapter 4 “Terminal
Assignment”:
The analogue current output is not capable of going below 4 mA, therefore when adjusting the designated
zero-point, the output signal has to be set slightly higher than that, just in order to check if said signal
does not virtually hang below 4 mA. If the output reacts immediately it can be set back to 4 mA, otherwise
the signal of the transducer has to be checked. If the current of 4 mA does not increase while loading a
force to the transducer the polarity of the signal has to be checked. If this is of negative polarity the signal
wires need to be interchanged.
If the circuit of the analogue current output is open somehow, this is indicated by a red LED on the pcb.

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In combination with a, transducer which is capable to handle tension and compression forces, an
analogue output of ± 10 volts is available. However, if a unipolar voltage is needed anyway, it is possible
to set the zero point of the transducer to volts of the output. This zero-point elevation is also necessary
for the analogue current output. ( V ± V equals 12 mA ± 8 mA) To lift the zero point to V the solder
point LP03 needs to be set.
4.4 Setpoints (option GW)
The setpoint characteristics are as follows:
GW2 = MAX; GW1= MIN (GW GrenzWert = SetPoint)
Notice: Other setpoint characteristics on request.
The 2 red LEDs in the lid signal the state of the relays, thus the setpoints.
Relays LED
Permitted state on off
None permitted state off on
Within the permitted range (SP1/MIN < current measuring value < SP2/MAX) all set-point relays are
activated. The relays drop out if a setpoint is under-run SP-1 or exceeded SP-2 or if the supply voltage
fails.
Notice: The setpoints are not pre-adjusted by the manufacturer. These settings have to be made by the
customer.
The maximum switching capacity is 30V/0, A
4.4.1 Setpoint settings
The setpoints can be set freely over the complete range of the measurement by using the potentiometers
P-100 and P-101 on the additional pcb (Althen 112). The adjustment may be executed either with loaded
sensor(-s), or by measuring the desired voltage on the pcb (Althen 112) on the measuring points (GW-
MP.1/2). The scaling of the GW-Test-signal equals
to the analogue output voltage.
The relays should be used for control signals only,
instead of switching heavy electrical loads.
The external wiring must be executed in a manner
that noises are suppressed.
Fig. 2 measuring points

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The test-signals are scaled as follows:
GW-test signal (Volt)
=
threshold (phys. unit)x 10 V
measuring range (phys. unit)
Notice: After adjusting the setpoints the potentiometers are to be sealed with anti-temper seal/
protective coating.
5 Starting up
If an adjustment (A-K-1K / A-D-1K) has been ordered in combination with the amplifier(-s) and/or
transducers(-s) it may be necessary for a slight fine adjustment nonetheless. This is due to possible various
environmental influences as well as to mounting etc.
If any visual damage or malfunctions are noticed, the measuring system must be switched off and marked
appropriately.
■ Mounting transducer and amplifier
■ Connect transducer to the amplifier
■ Connect multimeter to analogue output
■ Connect supply voltage – consider pin assignment
■ Allow the system about 30 min. to warm up
■ Check function and calibration of the system
Notice: The allocation of transducer / amplifier is to be complied with. After replacing a transducer, the
calibration has to be checked.
It is to be noted that there is a slight dependence between zero-point adjustment and amplification (gain).