6068 Description
The 6068 is a two-channel signal conditioning amplifier-digitizer
module featuring 100 kHz bandwidth and both digitized and analog
outputs. The base board contains both constant voltage with
remote sensing and constant current programmable excitation
supplies, high-bandwidth instrumentation amplifier with programmable
step and variable gain, nine-frequency six-pole lowpass
filter and dual buffered outputs. A plug-on module configures
the base board for multiple types of transducers including
voltage, full and partial bridge, voltage output charge (IEPE) and
charge output piezoelectric.
The input and excitation are isolated from the outputs, power and
control interface. This gives the user complete freedom to ground
the input without creating ground loops that introduce noise and
offset errors. It also provides up to 300 Volt common mode operating
voltage.
The differential instrumentation amplifier has programmable
gains from 1 to 5,000 and automatic zero. The two analog outputs
and the digitized output may be selected independently for
wideband or filtered response. The digital output is provided by
a successive approximation ADC at up to 200K samples per second
providing excellent time alignment between channels.
Voltage substation using an external source that is distributed to
all channel inputs provides traceable gain calibration.
6068 Function Cards
The 6068 uses a plug-in module to configure the input of each
channel for a particular type of transducer or specific type of
calibration. Modules can be easily modified or created to handle
special customer requirements. The more popular modules
are described here and include those for AC and DC coupled
voltage, full and partial bridges, and IEPE or piezoelectric
charge.
Bridge Modules
The bridge input is ten-wire shielded accommodating even the
most complex transducer wiring schemes. The base board provides
both programmable constant voltage with remote sensing
and constant current excitation. Programmable completion is
provided on the bridge module for quarter, half and full bridge
transducers. Automatic bridge balance
accommodates large unbalances
without limiting dynamic
range or loading the transducer output.
It can be used to provide voltage
offsets in the hundreds of millivolts
for non-bridge transducers such
as MEMS and variable capacitance.
The capability is provided for up to
four-steps of bipolar resistive shunt
calibration or DAC shunt calibration that provides 4096 calibration
steps using a single calibration resistor. The FC1 Bridge
Module shown has a single step of resistance shunt that can be
applied to either an external bridge arm or strain gage or to the
internal completion resistor. This module may also be used to
apply low-level voltage inputs, DC coupled, to the instrumentation
amplifier on the base board.
IEPE Modules
The IEPE module is for piezoelectric
and other transducers
with built-in electronics and a
voltage output. It provides consent
current excitation to the
transducer that is programmable
from 1 to 20 mA with 26 Volt
compliance. The output of the
transducer is AC coupled to the input of the instrumentation
amplifier on the base board.
Charge Modules
The Charge Amplifier module accepts charge signals from
piezoelectric transducers. It has
two charge ranges that accommodate
most charge transducers
and applications. Other customer
specified ranges.can be
provided. It has programmable
time constant that can be made
long or short as required and a
two frequency four-pole highpass
filter between the charge
amplifier output and the input to the instrumentation amplifier
on the base board. The filter is used to eliminate noise such
as cable whip. The filter may be bypassed for quasi-DC
measurements.
6068 Ordering Information
| 6068 |
Two-channel transducer amplifier, 100 kS/s, requires function card. |
Quote |
| 6068-FC1 |
Function card: Bridge, single shunt. |
Quote |
| 6068-FC2 |
Function card: IEPE, AC coupled voltage. |
Quote |
| 6068-FC3 |
Function card: Charge, piezoelectric. |
Quote |
[Call: 925-827-9010] 
