CWE TA-100 User manual

TA-100
Transducer Amplifier
©CWE 2023
Read instructions carefully before operating this device.
This device is not to be used for Human Life Support applications.
To avoid possible electrical shock, do not operate this device if is wet or has had liquids spilled onto it.
Service or calibration procedures should only be performed by qualified personnel familiar with the
electrical hazards of line-powered devices.
Ardmore PA 19003 U.S.A.
[phone]
[email protected]
Instruction Manual
www.cwe-inc.com

TA-100 Instruction Manual 2
© 2023 CWE, Inc.
STATEMENT OF WARRANTY
IF THIS INSTRUMENT FAILS WITHIN A PERIOD OF ONE YEAR FROM THE DATE OF
DELIVERY OR INSTALLATION, CWE, INC. WILL, AT ITS OPTION, REPAIR OR
REPLACE IT FREE OF CHARGE. THIS WARRANTY EXCLUDES DAMAGE
INCURRED THROUGH MISUSE OR ACCIDENT. CWE, INC. DOES NOT ASSUME ANY
LIABILITY FOR ANY CONSEQUENTIAL DAMAGES RESULTING FROM THE USE OF
THIS INSTRUMENT.
DEFECTIVE UNITS SHOULD BE RETURNED TO THE FACTORY ALONG WITH A
NOTE DESCRIBING THE NATURE OF THE FAULT. THIS WARRANTY IS
APPLICABLE TO THE ORIGINAL PURCHASER OF THE INSTRUMENT ONLY, AND IS
NOT TRANSFERABLE.
FACTORY SERVICE
Out of warranty or damaged instruments may be returned to the factory freight prepaid
for service at prevailing rates. Upon request, a written or verbal quotation for such service
will be issued after examination of the unit but prior to commencing repairs or service.
Address requests for service or technical information to:
CWE, Incorporated
Technical Support
Ardmore, PA 19003 U.S.A.
[phone]
[email protected]
LIFE SUPPORT POLICY
Instruments manufactured by CWE, Incorporated are not authorized for use as critical
components in human life support devices or systems. "Life support devices or systems",
as used herein, are devices or systems whose failure to perform, whether through misuse,
failure, or proper operation, can reasonably be expected to result in significant injury to
the operator or subject persons.
This manual last updated on 1/24/23

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© 2023 CWE, Inc.
1.0 INTRODUCTION
The TA-100 Transducer Amplifier is a compact, stand-alone amplifier for use with
all DC-bridge type transducers. Compatible transducers include blood or air
pressure, strain gauges, force transducers, and accelerometers. A built-in LCD
display shows the current measurement as well as a fast-response bar graph for
easy visualization of a rapidly changing signal. A serial port is also included,
allowing remote data collection using any simple terminal software.
The TA-100 features a wide gain range and a sharp-cutoff high frequency (low-
pass) filter. This filter includes a MEAN setting for producing a simple average of
the signal.
2.0 INPUT CONNECTION (rear panel)
Connect the transducer to the rear-panel INPUT jack. This is a 6-pin male
connector (WK-6-32S) used by Grass Instruments and other manufacturers. The
mating connector that should be on the end of your transducer cable is the WK-6-
21C.
If your transducer does not have the required connector, an adapter cable is
probably available. Please contact CWE, Inc, for information.
If you need to wire your own cable, the following table shown the proper pin
connections:
WK-6-21C Pin No.
Function
1
+ Excitation
2
+ Signal
3
- Signal
4
- Excitation (ground)
5
not used
6
shield
Note: Excitation voltage is factory set to 5.00V
Front panel view of TA-100 Transducer Amplifier

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3.0 BALANCE KNOB
This 10-turn dial is used to null out any imbalance in the transducer being used.
Normally, the transducer is set to a baseline condition (e.g. open to atmosphere),
and BALANCE adjusted until a zero output is obtained.
The range of this control as provided by the factory is +100mV. Additional balance
ranges (10mV and 250mV) are available by setting an internal jumper on the
circuit board.
4.0 GAIN SETTING
The TA-100 has a very wide amplification range (over three decades), allowing the
user to exactly tailor the amplifier to the transducer being used as well as the
output recording device (chart recorder, data acquisition system, etc.). Gain is set
using the 12-step GAIN switch, and the multi-turn ATTENUATOR trimpot. The
ATTENUATOR control permits precise gain settings that may be in between the
stepwise settings of the GAIN switch.
In practice, most users will simply plug in their transducer, and empirically adjust
the gain to get the desired output for a given input. The more mathematically
inclined can calculate the gain needed for a given situation. The following example
was used to determine the gain needed for measuring blood pressure using a
standard transducer (Vext is 5.00V):
Transducer parameters: 5V/Vext/mmHg
(i.e. the transducer output is 5V per volt of excitation per mmHg pressure)
Desired output voltage: 5V/300mmHg
The raw transducer output is 300mmHg x 5V x 5.00V = 0.0075V
The gain required is: 5V / 0.0075V = 666
To obtain this exact output, the gain switch is set to 1000X, and the attenuator control can
be adjusted counterclockwise to reduce this to 666X.
5.0 LOW-PASS FILTER
The FILTER switch applies a 2-pole low-pass filter to the signal. This is useful for
removing high-frequency noise coming from the transducer. The MEAN setting
provides a 0.1Hz filter, which is used to produce an average of the signal being
monitored.
6.0 LCD DISPLAY
The LCD display panel shows the actual output voltage being produced by the
amplifier. The nominal range of this signal is +8.0V.
The second line of the display shows a bar-graph corresponding to approximately
+3.5V. This display is useful for watching rapid changes in the signal.

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7.0 OUTPUT (rear panel)
This BNC jack is used to connect the output signal from the TA-100 to an external
monitoring or recording device. The usable range of the output signal is +8.0V.
8.0 SERIAL OUTPUT (rear panel)
A serial output is produced each time the LCD display is updated (approximately
every 200mS, or 50 times/second). This signal is in the following standard RS232
format: 9600,N,8,1.
The format is a simple ASCII string corresponding to the measurement shown on
the front-panel display, followed by <cr> and <lf> characters (13,10). This format
is easily accepted by any standard terminal program on a PC or Macintosh
computer.
9.0 POWER SUPPLY (rear panel)
The TA-100 is supplied with a small, universal input power supply providing 5VDC.
This power supply is suitable for use in any country.
WARNING! Use only the power supply provided with the
instrument. Use of a different power source could result in
permanent damage to the instrument!
TA-100 Setup Hints
Introduction:
To achieve the best Signal-to-Noise (S/N) performance, the user must consider the
amplitude and frequency range of the input signal. The GAIN and LO PASS FILTER settings
should thus be optimized to match the data acquisition system requirements.
Amplifier setup:
In general, we want to use the full output voltage range of the amplifier. This maximizes
the S/N ratio, because the signal of interest will overwhelm any baseline noise of the
amplifier. The following example will illustrate the process:
Blood Pressure Transducer example:
Almost all clinical-type BP transducers have the following signal size:
5uV / mmHg / Vexcitation
Since the TA-100 has a Vexcitation of 5V, this means the transducer will output 25uV
for each mmHg of pressure.

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Assuming you want a usable range of, say, 200mmHg, the signal from the BP
transducer would be in the range 0 –5000uV, or 5mV.
For many data-acquisition systems, the input range is around +5V. Therefore, we need
to boost the 5mV transducer signal to be, say, 2.5V which would allow room for growth,
but would still use a good part of the data-acquisition input range.
To find out what TA-100 gain is needed, simply divide the input voltage by the required
output voltage: 2.5V / 0.005V = 500X.
These settings would maximize the S/N ratio by using close to the full range of the TA-
100 amplifier, as well as a good part of the data-acquisition input a/d converter range.
You can see the actual output voltage of the amplifier by observing the front-panel LCD
display.
Filtering:
To further enhance S/N performance, the LO PASS FILTER should be used to match the
amplifier frequency response to the signal of interest. For BP measurements, a setting
of 500Hz or even 100Hz will work well.
Summary:
For best performance, always adjust the GAIN to use most of the output voltage range of
the amplifier, or to best match the input of the data-acquisition system.
10.0 ORDERING INFORMATION
Part No. Description
========= ================================================
08-14000 TA-100 Transducer amplifier
10-04100 DTX-1 Blood pressure transducer (requires TC-GRA adapter cable below)
10-04210 TC-GRA Adapter Cable for DTX-1 transducer
10-04010 PS-1000/A-1 Differential transducer, +70cmH2O range, not for liquids
10-04011 PS-1000/A-004 Sensitive differential transducer, +10cmH2O range, not for liquids