Interface BSC4A User manual

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Interface Inc. ● 7418 East Helm Drive, Scottsdale, Arizona 85260 USA ● www.interfaceforce.com
4-Channel Measuring Amplifier BSC4A
Operating Manual
Released June 19, 2023

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Interface Inc. ● 7418 East Helm Drive, Scottsdale, Arizona 85260 USA ● www.interfaceforce.com
4-channel strain gage measuring amplifier BSC4A
Description
The measuring amplifier BSC4A is a measuring amplifier with 4 independent channels for
sensors with strain gages such as force sensors, torque sensors, acceleration sensors or
extension sensors.
This measuring amplifier is also suitable for connecting strain gage full and half bridges
from 87.5 ohm to 5000 ohm and strain gage quarter bridges with 350-ohm.
The measuring amplifier BSC4A is supplied with a plug-in 18V power supply and SUB-D mating
plugs.
The voltage and current outputs are at the 15-pin Sub-D socket and one ground for each
analog output. Both outputs have been calibrated and can be used at the same time.
The sensor inputs, bridge competitions and the inputs for automatic zero adjustment of the
individual channels are at the 37-pin Sub-D socket.
The bridge completion resistance with 0.1% tolerance for 350-ohm strain gage is
maintained. The quarter or half bridge mode can be set by the customer at the 37-pin Sub-D
socket (see wiring diagram for 37-pin Sub-D socket ).
As an option, it is possible to use the 6-wire technology. The use of 6-wire technology must be
configured to the circuit board so this is a separate request that must be made at time of
purchase.
•4mV/V, 2 mV/V, 1mV/V, 0.5mV/V
configurable via jumpers
•Output signals ±10V AND 12mA+-8mA
on 15 pin Sub-D
•Integrated half and quarter bridge
completion for 350-ohm strain gage
•Tare function individually via control
cables and together via control cables
and switches

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Interface Inc. ● 7418 East Helm Drive, Scottsdale, Arizona 85260 USA ● www.interfaceforce.com
BSC4D M12 socket variant
The BSC4D M12 is optionally equipped with
round
connectors for the sensor connection.

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Interface Inc. ● 7418 East Helm Drive, Scottsdale, Arizona 85260 USA ● www.interfaceforce.com
Wiring diagram for 5-pin socket M12x1, type 763
5- pin Description Color code for cable
2 -US negative bridge power supply white white
1 +US positive bridge power supply brown brown
3 +UD positive differential input green blue
4 -UD negative differential input yellow black
View of socket side 5 AUX connected to
quarter bridge 350 ohm (QB)
grey grey
Six-wire technology is not possible for M12 socket variant.
In quarter bridge and half bridge mode, the internal half bridge completion must be activated
via the solder bridge on the circuit board (also possible in the factory as a free order option).
Wiring diagram for output socket 15-pin Sub-D socket
Socket
Spring contacts
BSC4A
assignment
15-pin SUB-D (PIN No.)
(Top view)
1
9
8 15
GNDio 1
black
Zero-point
adjustment (joint)
8
purple
Supply voltage 9
gray
Channel 1 Channel 2 Channel 3 Channel 4
Output voltage 2
brown
5
yellow
15
red-white
12
light green
Output current 3
red
6
green
14
brown-white
11
pink
Ground 4
orange
7
blue
13
black-white
10
white
The colors correspond to the core colors of the supplied 3-meter cable with 15-pin connector
SubD15.
Automatic Zero Adjustment
Automatic Zero-adjustment is operated via push button or via digital input. Advice: the GNDio
PIN 1 for digital input with PIN 8 is isolated from analog Ground PIN4.
Analog grounds PIN4, PIN7, PIN13, PIN10 are connected.
Connect GNDio (PIN1) permanently with Ground (PIN4) and connect Supply Voltage (PIN9) via
Relays or button with PIN8 for remote-controlled zero adjustment.

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Interface Inc. ● 7418 East Helm Drive, Scottsdale, Arizona 85260 USA ● www.interfaceforce.com
GNDio for digital input black, 1
Zero-adjustment input purple, 8
Supply Voltage output grey, 9
The colors correspond to the core colors of the supplied 3-meter cable with 15-pin connector
SubD15.
Wiring diagram for 37-pin Sub-D socket
37-pin Sub D, female
19 1
37 20
Terminal assignment 37 pin Sub D, female
BSC4A assignment 37-pin SUB-D (PIN No.)
GND Ground/shield 1
Channel
1
Channel
2
Channel 3 Channel 4
+US positive sensor power supply 20 2 11 29
+UF positive sensor input 21 3 12 30
+UD positive differential input 22 4 13 31
QB350 quarter bridge completion 350Ω 1) 23 5 14 32
HB half bridge completion 2) 24 6 15 33
-UD negative differential input 2) 25 7 16 34
-UF negative sensor input 26 8 17 35
-US negative sensor power supply 27 9 18 36
Tare automatic zero-point adjustment 28 10 19 37
1) Half bridge completion must be activated at the same time.
2) The negative differential input ( 25, 7,16, 34 ) must be connected to the corresponding
half bridge completion ( 24, 6,15, 33 ).
The automatic zero-point setting is done via push buttons or via the digital input. PIN 28 or
10 or 19 or 37. Note: The GNDio PINs for the automatic zero adjustment are separated from
the analog ground. Permanently connect GNDio (PIN1) to the ground of the supply voltage
and connect the supply voltage, but at least 3.5V with PIN 28 or 10 or 19 or 37 for remote
zero setting.

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Interface Inc. ● 7418 East Helm Drive, Scottsdale, Arizona 85260 USA ● www.interfaceforce.com
Wiring diagram of a full bridge to Sub-D-37, channel 1-4
BSC4A, Channel 1 / full bridge
BSC4A, Channel 3 / full bridge BSC4A, Channel 4 / full bridge
BSC4A, Channel 2 / full bridge
BSC4A BSC4A
BSC4A BSC4A

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Interface Inc. ● 7418 East Helm Drive, Scottsdale, Arizona 85260 USA ● www.interfaceforce.com
Wiring diagram of a half bridge to Sub-D-37, channel 1-4
BSC4A, Channel 1 / half bridge BSC4A, Channel 2 / half bridge
BSC4A, Channel 3 / half bridge BSC4A, Channel 4 / half bridge
BSC4A BSC4A
bridge bridge
bridge bridge
BSC4A BSC4A

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Interface Inc. ● 7418 East Helm Drive, Scottsdale, Arizona 85260 USA ● www.interfaceforce.com
Wiring diagram of a quarter bridge to Sub-D-37, channel 1-4
BSC4A, Channel 1 / quarter bridge BSC4A, Channel 2 / quarter bridge
BSC4A, Channel 3 / quarter bridge BSC4A, Channel 4 / quarter bridge
BSC4A
bridge bridge
bridge bridge
BSC4A
BSC4A BSC4A

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Interface Inc. ● 7418 East Helm Drive, Scottsdale, Arizona 85260 USA ● www.interfaceforce.com
Wiring diagram for a full bridge M12 variant
Wiring diagram for quarter bridges and half bridges M12 variant
Quarter bridge Half bridge
+Us brown
1
Aux grey 5
-Ud black
4
3
+Ud blue
+
-Us white 2
5-pin round connector
+Us brown 1
-
Aux grey
5
-Ud black
bl
4
3
+Ud ue
+
-Us white 2
5-pin round connector
Please note:
For quarter and half-bridge operation, the internal half-bridge supplement must be activated by
solder bridges on the printed circuit board (also possible at the factory ).
BSC4A / full bridge BSC4A / half bridge
BSC4A BSC4A

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Interface Inc. ● 7418 East Helm Drive, Scottsdale, Arizona 85260 USA ● www.interfaceforce.com
Adjusting the sensitivity
The sensitivity of channels 1 to 4 can be adjusted. On the circuit board of the
BSC4A, each channel has a jumper post field with 4 plug options in total.
4 mV/V
2 mV/V
1 mV/V
Jumper position
Sensitivity
0.5 mV/V
Channel 1
Channel 2 Channel 3
Channel 4

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Interface Inc. ● 7418 East Helm Drive, Scottsdale, Arizona 85260 USA ● www.interfaceforce.com
Opening the device
1. All 4 screw covers and the fastening screws on each end cover should be removed.
2. The cover with the (37-pin Sub-D socket) must be loosened using the two hexagonal
bolts.
3. The circuit board is unplugged from the side of the 15-pin Sub-D socket.
4. In the M12 socket version, the cover is pushed through the housing slightly slanted.
Technical data
Version
BSC4A
Unit
Accuracy class
0.1
%
Measurement range
configurable by jumper
±4; ±2 ±1.0; ±0.5
mV/V
Connectible full bridge
87..5000
See note limit below
*
ohm
Bridge supply voltage
5
V
Input impedance
>20 / 300pF
Mohm
Linearity deviation
<0.02
% of unit
Influence of temperature on the zero point per
10K in relation to the measuring range (of unit)
< 0.2
type 0.05
% of unit
% of unit
Influence of temperature on the measurement
sensitivity per 10K referring to the measured
value (RD)
< 0.1
type 0.05
% RD
% RD
Output filter analog output
3dB analog cut-off frequency, Bessel, 2nd order
250 Hz
Resolution
>20000 parts
Analog output voltage
Nominal range
Operating range
Output resistance
±10
±10.5
35
V
V
ohm
Analog output current
Nominal range
Operating range
Output resistance
12 ± 8 (alternatively 4-20)
12 ± 8 (alternatively 4-20)
35
mA
mA
ohm
Supply voltage
Nominal range
Operating range
12 … 24
10.5 ... 32
V
V
Power input max.
6
W
Zero adjustment
Tolerance
Duration
Resolution on falling edge after at least 4ms
high level (3.5V ... 30V or supply voltage)
<5, type <2.5
<90
mV
ms
Memory
Last zero position
Nominal temperature range
Storage temperature range
- 10…+65
- 40…+85
°C
°C
* Max. 2 channels can be operated with minimum sensor load of 87 ohm. The other 2
channels can be loaded with minimum 350 ohm. If the current outputs cannot be used, all

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Interface Inc. ● 7418 East Helm Drive, Scottsdale, Arizona 85260 USA ● www.interfaceforce.com
channels with a minimum sensor load of 120 ohm can be operated. This limit is necessary
for reasons of thermal stability .
Dimensions BSC4A M12
Dimensions BSC4A SubD37

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Interface Inc. ● 7418 East Helm Drive, Scottsdale, Arizona 85260 USA ● www.interfaceforce.com
Warranty
All instrument products from Interface Inc., ('Interface') are warranted against defective material and
workmanship for a period of (1) one year from the date of dispatch. If the 'Interface' product you
purchase appears to have a defect in material or workmanship or fails during normal use within the
period, please contact your Distributor, who will assist you in resolving the problem. If it is necessary to
return the product to 'Interface' please include a note stating name, company, address, phone number
and a detailed description of the problem. Also, please indicate if it is a warranty repair. The sender is
responsible for shipping charges, freight insurance and proper packaging to prevent breakage in transit.
'Interface' warranty does not apply to defects resulting from action of the buyer such as mishandling,
improper interfacing, operation outside of design limits, improper repair or unauthorized modification.
No other warranties are expressed or implied. 'Interface' specifically disclaims any implied warranties of
merchantability or fitness for a specific purpose. The remedies outlined above are the buyer’s only
remedies. 'Interface' will not be liable for direct, indirect, special, incidental or consequential damages
whether based on the contract, tort or other legal theory. Any corrective maintenance required after the
warranty period should be performed by 'Interface' approved personnel only.