Measurement Computing DBK Part 2 - Manual (Page 35)

DBK Option Cards and Module 899892 DBK43A & DBK43B, pg. 15
DBK43B Channel Types and Modes - Switch Positions
Channel Type 1
(Mode) 1
CAL1
Switch
CAL2
Switch
Function and Associated V
OUT
Equation
Bridge RUN
(Down)
RUN
(Down)
Sets the channel to read the value of the bridge circuit with all gains and offsets in
effect. This is the normal operation.
Vout = (Scaling Gain)(Filter Gain*)[(InputGain)(bridge circuit voltage) - offset voltage]
Offset
(SetOffset) RUN
(Down)
CL2
(Up)
Applies a grounded input to the channel. Sets the channel to read the circuit offset
voltage multiplied by the input amplifier and the low-pass filter gain.
Vout = (Filter Gain*)(Input Gain) - offset voltage
Input Gain
(SetInputGain)
RUN
(Down)
CAL2
(Up)
Applies 5 mV to the input channel. Sets the channel to read the voltage out of the
circuit through the input gain amplifier and the low-pass filter [if enabled].
Vout = (Filter Gain*)(Input Gain)(5 mV) - offset voltage
Scaling Gain
(SetScalingGain) RUN
(Down)
CAL2
(Up)
Applies 5 mV to the input channel. Sets the channel to read the voltage out of the
circuit through the input gain amplifier, the low-pass filter [if enabled], and the scaling
gain amplifier.
Vout = Filter Gain*(Scaling Gain[(Input Gain)(5 mV) - offset voltage])
Excitation CAL1
(Up)
CAL2
(Up)
Sets excitation.
Vout = (Excitation Voltage)
Shunt Cal CAL1
(Up)
CAL2
(Up)
Activates shunt-cal resistors.
Vout = (Scaling Gain)(Filter Gain*)[(Input Gain)( bridge circuit voltage with shunt) -
offset voltage]
DBK43B has two switches: CAL1/RUN and CAL2/RUN. DBK43A only has one switch; for that module refer to the previous
table.
* In the equations, the asterisk indicates the conditional clause, “if the filter is enabled.”
1 DaqView uses the term “Channel Type.” LogView uses the term “Mode.” In the first column the “type” and “mode” names
are often the same for DaqView and LogView. When there are differences the LogView “Mode” name appears in
parenthesis, for example (SetInputGain) is LogView’s mode equivalent of DaqView’s “Input Gain.”
DBK43B - Notes regarding CAL1 and CAL2
Mode CAL1 CAL2 Comments
RUN &
SET BRIDGE
RUN
(Down)
RUN
(Down)
Unlike the DBK43A, this run mode for the DBK43B allows for time
stamping and event marking without signal error. Both switches
“down” adds a grounded input to the channel and sets the channel
to read the circuit offset voltage multiplied by the input amplifier
and the low-pass filter gain.
CAL1
(Up)
RUN
(Down)
Not used. An invalid switch position.
SET INPUT GAIN,
SET OFFSET, &
SET SCALING GAIN
RUN
(Down)
CAL2
(Up)
Would simulate a DBK43A run mode. Used for setting input gain,
scaling gain, or offset.
SET EXCITATION &
SET SHUNT CAL
CAL1
(Up)
CAL2
(Up)
With both switches up, the calibration mode is enabled. The
mode is identical to that of the DBK43A when its single
CAL/NORM switch is positioned to “CAL.”