ALTHEN SG-IP-12E Series User manual

Single Channel Strain Gauge Amplifier
SG-IP-12E/24E-xxx
Germany | Switzerlan | 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
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Swe en
Althen Sensors & Control AB
Tel. [phone]
[email protected]
USA | Cana a
Altheris Inc Sensors & Controls Inc.
Tel: [phone]
[email protected]
Other Countries
please contact us
by email at
[email protected]
www.althen.de
V2.1 e
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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 ............................................................................................................................ 6
4.2 Strain gauge excitation voltage ................................................................................................... 7
4.3 Analogue output ............................................................................................................................... 7
4.3.1 Analogue output voltage ............................................................................................................. 7
4.3.2 Analogue output current ............................................................................................................ 8
 Starting up ................................................................................................................................................... 8
 .1 Zero point adjustment range ........................................................................................................ 9
 .1.1 Tare resistor ..................................................................................................................................... 9
 .2 Adjustment / calibration of the amplifier .............................................................................. 10
 .2.1 Correction of the analogue current output .......................................................................... 11
 .2.2 Calculation of amplification determing resistor ................................................................. 11
6 Maintenence ............................................................................................................................................. 12
6 Old appliances disposal ......................................................................................................................... 12
Appendix ........................................................................................................................................................ 13
Datasheet ....................................................................................................................................................... 13
Order designation ....................................................................................................................................... 13
Component diagram .................................................................................................................................. 14
Housing dimensions ................................................................................................................................... 14

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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
using accessories, that have been ordered from Althen Mess- & Sensortechnik GmbH together with the
measuring amplifier.
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 Safety 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 Qualifie 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 Inten e 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 escription
The described single-channel measuring amplifier serves to supply a strain gauge sensor with a full
bridge resistance of 300 ohms or more and the amplification of the sensors signal. Standard analogue
outputs are available for further evaluation.
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.

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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 instructions
must be complied with.
Clamp Description Clamp Description
1
+Supply voltage (+Ub) 6 + Signal
2
Supply ground (Ub) 7 - Signal
Galvanic isolation 8
+ Excitation
3
Analogue output 2 (version 4 … 20 mA) 9 - Excitation
4
Analogue output 1 (0 … +10 V or. ±10 V)
10
Housing / Shield
Analogue output ground
Terminals “supply ground” and “analogue ground” are isolated galvanically. To unset this isolation clamp
2 and are to be bridged.
4.1 Supply 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.
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.
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 and have to be bridged.

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4.2 Strain gauge excitation voltage
The described measuring amplifier is able to supply one strain gauge transducer. Any strain gauge full
bridge with a bridge resistance of 300 ohms or more may be connected. The transducer can be supplied
with either 10 VDC or VDC unipolar voltage. This value can be selected with a solder point (LP-01) for
coarse, and with a potentiometer (P-0 ) for fine adjustment.
LP-01 Excitation voltage
Set 10 VDC
Not set VDC
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 an 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 the solder point
LP03 needs to be set.

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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.
In combination with a transducer, which is capable to handle tension and compression forces, an
analogue output of ± 10 volts is available. However, if an 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.
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).

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5.1 Zero point a justment range
It is to be noted that there is a slight dependence between zero-point adjustment and amplification
(gain).
The zero-point adjustment range is approx. ± 10 %.
This range can be changed by setting the dip-switch according to the table below:
S01-1 S01-2 S01-3 S01-4 corresponding to the analogue voltage output
ON ON ON ON -1,4 V … +1,4 V
ON OFF OFF ON - V … + V
ON OFF ON OFF +0,6 V … +6, V
OFF ON OFF ON -6, V … -0,6 V
5.1.1 Tare resistor
A potential base load can be electrically suppressed by an additional resistor on the pcb, if an expansion
of the zero-point adjustment range is not sufficient. (R tara )
The value of the resistor can be found in the table below. The resistor is then to be soldered to the solder
pins (Rt) on the pcb. In addition, the solder point (LP-02) has to be set to + or –, corresponding to the
tare-load.
R TARA [kΩ] Range
180 100% full range output
380 0 % full range output
780 2 % full range output
Notice A base load reduces the remaining load capacity by just that value. Overloading may cause
damage!
Base load/ tare + maximum load to measure = capacity of transducer

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5.2 A justment / calibration of the amplifier
In order to adjust or calibrate the amplifier at least one multimeter has to be connected to one of the
analogue outputs. Preferably analogue output voltage.
Notice The calibration of the amplifier in general is done with the potentiometer P-02. This basic
calibration adjusts the analogue voltage output. The analogue current output follows the voltage
output. Thus, the analogue current output does not need to be corrected – it is been done right in the
factory. If, however, the current output does need an adjustment, it can be done by potentiometers
P-03.
Inspection:
■ Unload the measuring device.
■ Connect the multimeter (refer to chapter 4 “Terminal Assignment”).
■ Set the analogue output to 0 Volts resp. 4 mA.
■ Load the measuring device (i.e. the transducer) at least 3 times fully.
■ Load the device with 80 % of its maximum load.
■ Check if the analogue outputs comply with the load and is in the designated specs.
■ If not, the measurement system might need to be recalibrated. Above that, the installation
position and the overall setup might need an inspection.
Adjustment / Calibration:
The coarse amplification, and thus the voltage output, is determined by an internal resistor (R G ) and
can be fine adjusted by a potentiometer. (P-02). To adjust the current output, which follows the voltage
output, the potentiometer P-03 is to be used. (See next chapter.)
Before the calibration a warm-up time of approx. 30 mins should be kept. The measuring device is to
be unloaded.
Unloaded means with:
Force transducers: no applied force at all
Pressure transducers no pressure, except atmospheric influence
■ In this unloaded state adjust the zero-point with the potentiometer P-01.
■ Apply a defined load. (by calibrated weights, pressure generator etc.)
■ Adjust the analogue output corresponding to the applied load.
In or er to reach the require accuracy, it may be necessary to repeat these steps.