DBK43A & DBK43B
8-Channel Strain Gage Modules
Features• Provide eight channels of strain gageinput
• Accommodate most bridge-type­sensors, including 4-element full and3-wire quarter bridges• Contain an individual excitation regulator per channel, and a user-selected
low-pass filter
The DBK43 eight-channel strain gage
expansion modules for IOtech’s dataacquisition systems accommodate moststrain gage types, and configurations fromsingle-element, 3-wire quarter bridges to4-element full bridges and load cells. TheDBK43 modules also include provisions forbridge completion resistors and provides
four externally accessible adjustments oneach of their eight channels, for excitation
voltage, input gain, offset nulling, andoutput scaling.
The DBK43 modules include a built-in
DC/DC converter, which lets the unit
operate from an external power source
and requires little power from the dataacquisition system.
The DC/DC converter also provides excitation voltages for all channels. Each of
the eight on-board excitation regulators
can be externally adjusted from 1.5 to10.5 VDC. The regulator outputs haveremote sensing terminals and feature
50 mA current limiting to prevent damage from short-circuits or overloads. The
wide regulator voltage range allows any
resistor or semi-conductor type gage tobe incorporated into a system.

DBK43ADBK43BThe DBK43 modules provide eight channels of strain gage input

DBK43A’s Typical Bridge Configuration (for one of 8 channels)
1/8 (DBK43A)
Bypass±15V

Measurement Computing

Scaleadj

Excitation
voltageregulator

0.33 µF

LPF(Av = 2)Scale
V2 ampUserstraingagebridge

Optional Kelvinexcitation connection

5R244

Optional Kelvinexcitation connection

CAL

VIN

MUX

21R25100Ohm
ShuntCal.

Offset and Scaling Gain. Each DBK43’s
0 to 5 VDC offset adjustment range andoutput-gain scaling permit nulling of large
quiescent loads and expansion of dynamic
range for maximum resolution. This is an
important feature because strain gages(508) 946-5100

1To P1

Optional
bridgecompletion
resistors

100Ohm3VOUT

A v = A 2 (1-10)+V +5 –V –5
6Input Amplifier. Each DBK43’s input
amplifiers provide an input gain rangeof x100 to 1250. Input signals can vary
widely in range, which makes the DBK43’s
a superior alternative to fixed-gain or slotrange amplifiers.
Data Logging. The DBK43B supports timestamp mode when used with the LogBook.
Although the DBK43A can be used with
the LogBook, it does not support datatimestamping.

Bypass

Exc.
adj+
Input
amp–VoViAv = Ai
(100-1250)

Offset null
Offset
adj.
0-5.0
VDC

­typically exhibit pre-load or ­quiescent output, which leads to a non-zero output prior
to the application of the load to be measured.
The ­remaining signal can then be expandedby the DBK43’s output scaling amplifiers toincrease the resolution.

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DBK43A & DBK43B

Specifications & Ordering Information
Shunt-Calibration Feature. The DBK43
modules offer locations in each channel
amplifier for user-supplied shunt calibration resistors. This feature allows you tosimulate, under software control, a pre-set
bridge disturbance to aid in calibrationand ­verification of each channel setting.
Coupling and Filtering. Each DBK43 channel features a user-selectable AC or DC
coupling between the input amplifier circuits, and a selectable 3-pole, low-pass filter
with user customizable cut-off frequency.
Elective capacitive coupling, which is selected via user-installable jumpers, allows
separation of dynamic signals from static
deflection levels.
Bridge-Completion Resistors. Physicallocations are provided for up to fourbridge-completion resistors per channel,
allowing you to accommodate most typesof external configurations without having
to attach bridge completion resistors to
the strain gage.
Connectivity. The DBK43A provides molded
cable connectivity to the unit, and a barewire termination for connection to thestrain gage sensor. The DBK43B has amodular screw-terminal connection forbare wire termination at both ends of thecable. The DBK43B allows for custom wirelengths and quick wiring re-configuration.

SpecificationsConnectors
DBK43A: P1* DB37; mini-DIN6 for strain-gage orexternal excitation connections
DBK43B: P1* DB37; removable screw-terminal blocks
for strain-gage or external excitation connections
Number of Channels: 8
Operating Temperature Range
DBK43B: -30 to +60 ˚CExcitation Voltage Adjustment Ranges: 1.50 to10.50 VDC @ 50 mA
Input Gain Range: x100 to 1250; separate instrumentation amplifier for each channel with gain
adjustable via externally accessible 15-turn trimpot
Accommodated Bridge Types
Full bridge, Kelvin excitation (6-wire)
Full bridge (4-wire)
Half bridge (3-wire)
Quarter bridge (3-wire)
Bridge-Completion Resistors: On-board resistor
socket locations (Rn00A, Rn00B, Rn00C, Rn00E,Rn00F, and Rn00G) for 6 bridge-completion
resistors per channel
Input Type: Differential
Input Impedance: 100 MOhm parallel with 100 pF
CMMR: 115 dB (DC to 60Hz.)
Excitation Current Output: 50 mA max(current limited @ 60 mA)
Excitation Sensing: Local or remote
Excitation Regulation
Line Regulation: 0.01% typ, 0.1% max
Load Regulation: 0.03% typ, 0.2% max
Gain Calibration Reference: 5 mVDC
Gain Calibration Reference Accuracy: 0.2%
Gain Calibration Reference Drift: 20 ppm/˚CGain Accuracy: 0.5%
Gain Drift: 50 ppm/˚C
Input Offset: 40 µV typ, 200 µV max(offset adjustable to zero)
Input Offset Drift: 1 µV/˚C typ, 4 µV/˚C max**
Output Offset: 2 mV typ, 8 mV max(offset adjustable to zero)
Output Offset Drift: 100 µV/˚C, 200 µV/˚C max**
Offset Adjustment: 0 to 100% of range, 0 to 5 VDC(15-turn trimpot)

Full-Scale Sensitivity Range
5.00 VDC Excitation: 0.8 to 10 mV/V
.10.00 VDC Excitation: 0.4 to 5 mV/V
Scaling Amplifier Gain Range: x1 to 10(15-turn trimpot)
Low-Pass Filter:   3-pole, user-selected; corner frequency (Fc) set by user component; attenuation-3 dB at Fc ; gain x2
Power: 9 to 18 VDC, external supply provided,
16 Watts maximum
Dimensions: 285 mm W x 221 mm D x 35 mm H
(11” x 8.5” x 1.375”)
Weight: 1.3 kg (3 lbs)

Ordering Information

Description
8-channel strain gage module
8-channel strain gage module withscrew-terminal connection

Part No.
DBK43ADBK43B

Accessories
120 Ohm bridge-completion resistor
350 Ohm bridge-completion resistor
1000 Ohm bridge-completion resistor
Rack mount kit
Additional blank header

BCR/120/1
BCR/350/1
BCR/1000/1
RackDBK2
CN-115

CablesSet of eight 6 ft. cables with mating
mini-DIN 6 connector for DBK43A
Molded T expansion cable; 2 in.
Molded T expansion cable; 4 in.
Ribbon cable, where x is the numberof DBK devices attachedCA-132
CA-255-2T
CA-255-4T
CA-37-x

Note: The CA-37-x ribbon cable can also be usedin lieu of the CA-255-x molded T cables.

CA-132, eight strain gage cables for DBK43A* Attachment to the DaqBoard/2000 Series requires a DBK200, DBK202, DBK203A, DBK209, DBK213, or DBK214** Total drift (referred to inpt) is Input Offset Drift +Measurement Computing

Output Offset Drift
Input Gain (as set by timpot)(508) 946-5100

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