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Strain Gauge Measuring Amplifier BA 662
Original of the
Manual
Table of Contents
1. Safety precautions ........................................................................................................... 2
1.1. Field of application ....................................................................................................... 2
1.2. Installation ................................................................................................................... 2
1.3. Maintenance ................................................................................................................ 2
2. Function ............................................................................................................................ 2
3. Specifications ................................................................................................................... 3
3.1. General technical data ................................................................................................. 3
3.2. Circuit diagram ............................................................................................................ 4
3.3. Dimensions .................................................................................................................. 4
3.4. Connections ................................................................................................................ 5
3.5. How to connect signal output ...................................................................................... 5
3.6. Trigger input ................................................................................................................ 5
4. Operation .......................................................................................................................... 6
4.1. Overview operating elements BA662/IP20 .................................................................. 6
4.2. How to operate the keys .............................................................................................. 6
4.3. Amplification ................................................................................................................ 6
4.4. Zero alingment ............................................................................................................ 7
4.5. Filter ............................................................................................................................ 7
4.6. Signal output ............................................................................................................... 7
4.7. LED Status .................................................................................................................. 8
4.8. Restart ......................................................................................................................... 8
4.9. Factory setting (RESET) .............................................................................................. 8
5. Using the Software ASTAS (USB) ................................................................................... 8
6. EC Declaration of Conformity ......................................................................................... 9
Technical changes reserved. 09/2016 Page 1 of 10
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Manual BA 662
1. Safety precautions
In this operating manual, the installation, putting into operation and the operation itself of the
Strain Gauge Bridge Amplifier BA 662 is described. It is assumed that all measures are taken
by qualified staff only who have adequate knowledge in the fields of measuring and control
engineering.
ATTENTION! Any non-compliance with these safety precautions may result in
severe damage to property and health.
1.1. Field of application
The Strain Gauge Bridge Amplifier BA 662 has been designed to the purpose of amplifying the
output signals of sensors with metal-foil strain gauges, preferably force transducers and
transform them into standard signals. Any other application is regarded contrary to the
intended purpose. The manufacturer does not accept any liability for damages resulting from
such inappropriate usage. In this case it is the user alone who has to bear the risk.
Type BA 662 must not be used as the sole means to prevent dangerous conditions of
machines and plants. All machines and plants must be constructed in such a way (e.g. by
using mechanical stops, limit switches) that a condition of failure does not result in a situation
of severe danger.
It must be made sure that any erroneous setting or malfunction of the unit or its breakdown
cannot cause damage or be a risk to the operating staff or other persons.
1.2. Installation
The unit must be installed and connected in compliance with the current DIN- and VDEstandards. Supply cables and signal lines shall be installed so that interference signals such as
electrical interference do not have any adverse effects on the function of the equipment.
1.3. Maintenance
The device does not contain any components that require maintenance. Repairs shall be
carried out by the manufacturer only.
2. Function
The Strain Gauge Bridge Amplifier BA 662 is a digital amplifier for the low-drift amplification of
the output signals of sensors with metal-foil strain gauges, preferably force transducers to
supply a standard signal of (-10/0...10) VDC or (0/4...20) mA.
An internal voltage source provides the stabilized feeding voltage for the sensor. The power is
supplied by an unstabilized source of (9...36) VDC. The Strain Gauge Bridge Amplifier is
delivered in a case for standard rails in accordance with DIN EN 50022-35.
The BA 662 is delivered with a factory setting for an input signal of 2mV/V and a corresponding
output signal of ± 10V or 20mA. The other input signal ranges 0.1mV/V to 7mV/V can be
generated internally from the 2mV/V factory adjustments. The different settings of the factory
adjustments (zero point and gain) can be changed by the user through keys.
By an optically separated input, the zero-setting can be carried out by means of a superior
control and through the trigger input. The overload limit is not affected by such a zeroing, which
means that 100 % of the end-value adjustment of the sensor remains as end value. An existing
preload by a container can thus be set zero.
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Manual BA 662
3. Specifications
3.1. General technical data
Class of accuracy at input signal
2mV/V
% FSR < 0.02 (typ.)
Connection for strain gauge sensor 4- or 6-wire
Bridge resistance / range of input
impedance
Input signal range (+Si/-Si)
Excitation voltage (+Ex/-Ex)
Norm Output
Current Output
Voltage Output
Load resistance
Measurement Characteristics
Ω
mV/V
VDC
58...2000 (up to 6 loadcells each 350 Ω)
0.1 / 0.25 / 0.5 / 1.0 / 1.5 / 2.0 / 3.0 / 4.0 / 5.0 /
7.0
±2.5
mA
V
Ω
0/ 4... +20; 0…24
≤ 500
-10/-5...0…+5/ +10
Conversion rate Hz 6 …. 3200
Resolution of the A/D Converter Bit 24
Filter Hz 0.8…2000
Error at S=2mV/V
Nonlinearity
Noise (at measurement rate)
Input sensitivity for 1 LSB
Zero drift
Power Supply
Input range
Power consumption (without sensor)
Environmental Conditions
Operating temperature range
Storage temperature range
Construction
Weight
Dimensions (W x H x D)
Environmental protection (EN 50529)
Terminal block, wire size
%FSR
%FSR
nV
%/ 10K
0.002 (0.8Hz) … 0.009 (2000Hz)
0.0025
150
<0.01
VDC
W
9 ... 36
1
°C
°C
- 20...+ 60
- 25...+ 85
Plastic housing for DIN-rail mounting
kg
mm
mm²
22.5 x 114.5 x 99
0.2
IP 20
0.14 … 2.5
*Software
- Download over www.ast.de
≥ 1000
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Manual BA 662
T
T
2
2
3.2. Circuit diagram
Sensor
3.3. Dimensions
99
Power supply
9 ... 36VDC0V
±12V
+Se
+Ex
+Si
Si
-
2.Stab
1.Stab
A
D
C
μC
16-Bit
-DAC
Output
I
Out
V
Out
AG
Ex
-
Se
-
Shi
2’. Stab
EMC-Filter
Filte r
DIP-Switcher
(
Config. DAC
)
+ 24VDC
- 0V
USB:
114,5
(ASTAS*, Configuration DAC, Filter)
+Si -Si
-Ex +Ex
NC SHI
-Se +Se
BA 662
6-Wire
4-Wire
mV/V
0.5
1.0
0.25 1.5
Filter (Hz)
25
8,3
2,4
Output
156
0,8
38567
625
1315
2000
0 ... 10V
0 ... 5V
-10 ... +10V
-5 ... +5V
0 ... 20mA
0 ... 24mA
4 ... 20mA
0.1 2.0
7.0
USB
3.0
4.05.0
+
100%
-
Reset
+
0%
-
AG
24V
Status
V
OUTIOUT
0V
Tr-
NC
Tr+
,5
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Manual BA 662
3.4. Connections
Terminal connection Description
-Ex neg. Exitation voltage
-Se neg. Sense signal
+Se pos. Sense signal
+Ex pos. Exitation voltage
+Si pos. Signal
Sensor with
6-wire
-Si neg. Signal
NC not connected
SHI Shield
AG Ground for output signal
V
Voltage output
out
I
Current output
out
Outuput signal
NC not connected
24V Supply voltage
0V Supply voltage ground
Tr+ Trigger 24V
Tr- Trigger 0V
Power supply
electrically isolated input
Installation recommendations
Use shielded cables.
Use the largest possible cable cross section (Error due to cable extension).
Lay the measuring lines separately from the power supply lines.
At the force transducers and the measuring amplifier, make as short as possible a
connection to earth, in particular in strong electromagnetic fields.
Additionally, lay an equipotential bonding parallel to the measuring line.
Keep away from stray fields of motors, transformers and contactors.
Connect force transducers, amplifier, mains unit, and indicator / processor unit with earth in
one place only.
Set the slide switch for the sensing line (6- or 4-wire) according to the sensor connection.
3.5. How to connect signal output
The Bridge Amplifier BA 662 provides different output signals, depending upon the setting of
the slide switches. (see 4.6)
NOTE Either the current output or the voltage output can be used, not both at the
same time.
TIP: o form the sum, current outputs of several BA662 can be connected in parallel. In
this case, 12V should not be exceeded at the standard output and the maximum load
(load resistance) be <12V / I
.Voltage outputs must not be connected in parallel.
Out
3.6. Trigger input
The BA662 has an optically separate trigger input so that the zero-setting can be carried out by
means of a superior control. The overload limit is not affected by such a zeroing.
The function is started by a 24 VDC trigger impulse.
Note! The measuring amplifier is protected against reverse polarity.
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Manual BA 662
4. Operation
4.1. Overview operating elements BA662/IP20
BA 662
6-Wire
4-Wire
0.5
1.0
0.25 1.5
0.1 2.0
7.0
4.05.0
USB
+
100%
Reset
+
Status
mV/V
3.0
-
0%
-
Connection
Sensitivity/
measuring range
of sensor in mV/V
Amplification
Push simultaneous:
Load calibration
Factory setting
(RESET)
Zero:
Push simultaneous:
Zero calibration
LED: Status
Filter (Hz)
67
25
8,3
2,4
Output
156
0,8
385
625
1315
2000
0 ... 10V
0 ... 5V
-10 ... +10V
-5 ... +5V
0 ... 20mA
0 ... 24mA
4 ... 20mA
4.2. How to operate the keys
Keys individually / short: Setting of the signal output
Keys individually / long (2s): Fast setting of the signal output
4.3. Amplification
Switch position 0 1 2 3 4 5 6 7 8 9
Measuring range (mV/V) 0,1 0,25 0,5 1,0 1,5 2,0 3,0 4,0 5,0 7,0
>100% +< and >100% -< simultaneously (2s):
Adjustment of the present input signal (currently applied force) to100% of the output signal
(end-value adjustment).
By individually pushing the keys >100% +< or >100% -< respectively, an individual fine
adjustment of the output signal / the end value is possible.
NOTE In case of changing the amplifier output by means of keys > 100 % +< or >
100% -< there should always be a zero-alignment check.
NOTE Amplification-values are saved permanently 7 seconds after last push button
action. During saving LED blinks for a short time.
Page 6 of 10 Technical changes reserved. 09/2016
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Manual BA 662
4.4. Zero alingment
>0% + < and >0% - < simultaneously (2s):
Setting of the present input signal at the output to zero point (zero-adjustment/ zero-alignment)
By individually pressing the keys >0% +< or >0% -< respectively, an individual fine adjustment
of the output signal / the zero point is possible.
NOTE! Zero-values are saved permanently 7 seconds after last push button action.
During saving LED blinks red for a short time.
4.5. Filter
Through a low-pass filter, the output signal can be set in 10 stages, from 0.8 to 2000Hz.
Filter (Hz) 0,8 2,4 8,3 25 67 156 385 625 1315 2000
Internal Sample rate (Hz) 6 12 25 50 100 200 400 800 1600 3200
4.6. Signal output
DIP-switch explanation: DIP-switch function:
- OFF -
0 … +10V
0 … + 5V
-10 … +10V
3 2 1
-5 … + 5V
0 … 20mA
0 … 24mA
4 … 24mA
ATTENTION! In case of exceedance of the input signal of >-120%, the analogue
output is set to the maximum positive initial value.
In case the input signal lies in the range between -120% and 0%, the minimum
analogue signal is released at the unipolar voltage output and the current output
respectively (see too 4.7).
o
utput bipolar
(U)
o
utput
uni polar ( U/ I)
Input
120%
120%
-
Graph 1
Output signal in case of error (bipolar)
Output signal -5…5V, -10…10V
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-
120%
120%
Input
Sensor mV/V
Graph 2
Output signal in case of error (unipolar)
Output signal 0…5/10V, 0/4…20/24mA
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Manual BA 662
4.7. LED Status
LED display Explanation Error description
Green Ready for operation
No error
Error at connections of sensor lines
Red 1 x flashing ADC-Overload
Cable break in sensor line
Switch for 6- and 4-wire not accordingly
connected
Red 2x flashing
Indicates overload
or underload
Exceed of maximum load of 120% of nominal
sensitivity, or exceed minimum load (see too 4.6)
Error in the memory of the automatic sensor
Red 3x flashing TEDS error
recognition
(only option with TEDS)
Red 4 x flashing Output > 100%
Red 5 x flashing
Current output open
or overheating DAC
The amplification at the output is set too high.
Output side not closed
Cable break at output
Thermal overheating - cooling necessary
Red 6 x flashing Hardware error
General error – restart necessary
4.8. Restart
100% - and >0% +< simultaneously: A restart is carried out. All settings are saved.
4.9. Factory setting (RESET)
For all ten sensitivity settings / measuring ranges (see 4.1 – sensitivity in mV/V of the sensor)
factory settings are stored in the amplifier.
Individual adjustments of the amplification (see 4.3.) or of the zero point (see 4.4) carried out
later by the user, do only influence the active measuring range that has just been set.
When simultaneously pushing the two keys >100% +< and >0% -< for 2s, all zero-point
adjustments and end-value adjustments of all ten measuring ranges are deleted and reset to
the factory settings of 0mV/V ≙ initial value of the selected signal output (-5/-10/0V or 0/4mA)
and 2mV/V ≙ end value of the selected signal output (5/10V or 20/24mA).
NOTE! After reset to factory settings, the amplifier has to be newly adjusted to the
sensor!
5. Using the Software ASTAS (USB)
Load the software from our website www.ast.de
TIP: Linearization: If the measured values between zero and rated load should
deviate from the real load, up to four additional points can be set to increase the
measurement accuracy. These measuring points can be made in any order, similar to
the input of the zero point and end point. After entering all of the calibration points, the
result must be stored.
Page 8 of 10 Technical changes reserved. 09/2016
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Manual BA 662
6. EC Declaration of Conformity
Technical changes reserved. 09/2016 Page 9 of 10
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Manual BA 662
Page 10 of 10 Technical changes reserved. 09/2016
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