NPI DPA-2FL User manual

OPERATING INSTRUCTIONS AND
SYSTEM DESCRIPTION FOR THE
DPA-2FL
LOW-NOISE DIFFERENTIAL
AMPLIFIER / FILTER MODULE
FOR EPMS SYSTEMS
VERSION 1.1
npi 2010
npi electronic GmbH, Hauptstrasse 96, D-71732 Tamm, Germany
Phone [phone]; Fax: [phone]
[email protected]; http://www.npielectronic.com

DPA-2FL User Manual
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Table of Contents
1. Safety Regulations............................................................................................................ 3
2. EPMS-07 Modular Plug-In System.................................................................................. 4
2.1. Components of the EPMS-07 Housing ....................................................................... 4
2.2. General System Description / Operation..................................................................... 4
2.3. System Grounding....................................................................................................... 5
2.4. Technical Data.............................................................................................................5
3. DPA-2FL Differential Amplifier / Filter Module ............................................................ 6
3.1. DPA-2FL Components................................................................................................ 6
3.2. System Description...................................................................................................... 6
3.3. Signal Flow Diagram................................................................................................... 6
3.4. Description of the Front Panel and Operation............................................................. 7
4. Literature.......................................................................................................................... 10
5. Technical Data.................................................................................................................. 11

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1. Safety Regulations
VERY IMPORTANT:Instruments and components supplied by npi electronic are NOT
intended for clinical use or medical purposes (e.g. for diagnosis or treatment of
humans), or for any other life-supporting system. npi electronic disclaims any
warranties for such purpose. Equipment supplied by npi electronic must be operated
only by selected, trained and adequately instructed personnel. For details please consult
the GENERAL TERMS OF DELIVERY AND CONDITIONS OF BUSINESS of npi
electronic, D-71732 Tamm, Germany.
1) GENERAL: This system is designed for use in scientific laboratories and must be
operated only by trained staff. General safety regulations for operating electrical devices
should be followed.
2) AC MAINS CONNECTION: While working with the npi systems, always adhere to the
appropriate safety measures for handling electronic devices. Before using any device
please read manuals and instructions carefully.
The device is to be operated only at 115/230 Volt 60/50 Hz AC. Please check for
appropriate line voltage before connecting any system to mains.
Always use a three-wire line cord and a mains power-plug with a protection contact
connected to ground (protective earth).
Before opening the cabinet, unplug the instrument.
Unplug the instrument when replacing the fuse or changing line voltage. Replace fuse
only with an appropriate specified type.
3) STATIC ELECTRICITY: Electronic equipment is sensitive to static discharges. Some
devices such as sensor inputs are equipped with very sensitive FET amplifiers, which can
be damaged by electrostatic charge and must therefore be handled with care. Electrostatic
discharge can be avoided by touching a grounded metal surface when changing or
adjusting sensors. Always turn power off when adding or removing modules,
connecting or disconnecting sensors, headstages or other components from the
instrument or 19” cabinet.
4) TEMPERATURE DRIFT / WARM-UP TIME: All analog electronic systems are
sensitive to temperature changes. Therefore, all electronic instruments containing analog
circuits should be used only in a warmed-up condition (i.e. after internal temperature has
reached steady-state values). In most cases a warm-up period of 20-30 minutes is
sufficient.
5) HANDLING: Please protect the device from moisture, heat, radiation and corrosive
chemicals.

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2. EPMS-07 Modular Plug-In System
2.1. Components of the EPMS-07 Housing
The following items are shipped with the EPMS-07 housing:
 EPMS-07 cabinet
 Power cord
 Fuse 2 A / 1 A, slow
 Front covers
2.2. General System Description / Operation
The npi – EPMS-07 is a modular system for processing of bioelectrical signals in
electrophysiology (see Figure 1). The system is housed in a 19” rackmount cabinet (3U)
containing a power supply and has room for up to 7 plug-in units. The plug-in units are
connected to power by a bus at the rear panel.
The plug-in units must be kept in position by four screws (M 2,5 x 10). The screws are
important not only for mechanical stability but also for proper electrical connection to the
system housing. Free area must be protected with covers.
In order to avoid induction of electromagnetic noise the power supply unit, the power-switch
and the fuse are located at the rear of the housing.
Figure 1: Example of a measurement system located in an EPMS housing with two channel
iontophoresis and balance module (MVCS-02, MVCC-02), bridge amplifier
module (BRAMP-01R) and an extracellular amplifier module (EXT-01C)

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2.3. System Grounding
The 19" cabinet is grounded by the power cable through the ground pin of the mains
connector (= protective earth). In order to avoid ground loops the internal ground is isolated
from the protective earth. The internal ground is used on the BNC connectors or GROUND
plugs of the modules that are inserted into the EPMS-07 housing. The internal ground and
mains ground (= protective earth) can be connected by a wire using the ground plugs on the
rear panel of the instrument. It is not possible to predict whether measurements will be less or
more noisy with the internal ground and mains ground connected. We recommend that you
try both arrangements to determine the best configuration.
2.4. Technical Data
- 19” rackmount cabinet, 3U high (1U=1 3/4” = 44.45 mm), for up to 7 plug-in units
- Power supply: 115/230 Volts AC, 60/50 Hz, fuse 2 A / 1 A slow, 45-60 W

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3. DPA-2FL Differential Amplifier / Filter Module
3.1. DPA-2FL Components
The following items are shipped with the DPA-2FS system:
 Amplifier / Filter module for the EPMS-07 system
 User manual
3.2. System Description
The DPA-2FL differential amplifier/filter is a plug-in unit for the npi EPMS-07 modular
system. The DPA-2FL is designed to amplify and filter very small bio-electrical signals. The
input voltage range is ±12 V, the inputs are protected up to 15 V. All inputs and the output are
BNC connectors.
The input impedance is 1 M. Using the differential input configuration common mode
signals and noise are removed allowing recordings of signals with very small amplitudes. An
optional NOTCH filter removes 50 Hz / 60 Hz noise.
DC offsets can be compensated either by the using the OFFSET control or the HIGH PASS
filter.
The GAIN range is x10 to x10000 and the output signal is passed through the HIGH PASS,
LOW PASS and NOTCH filter.
Important:To avoid noise interference the respective toggle switch should be in the zero
position if one of the inputs is not used.
3.3. Signal Flow Diagram
The signal is passed through the DPA-2FL as shown below.

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3.4. Description of the Front Panel and Operation
Figure 2: DPA-2FL front panel view
In the following description of the front panel elements each element has a number that is
related to that in Figure 2. The number is followed by the name (in uppercase letters) written
on the front panel and the type of the element (in lowercase letters). Then, a short description
of the element is given.

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OFFSET unit
The OFFSET unit consists of (1) OFFSET RANGE switch, (2) OFFSET
potentiometer and (3) ZERO ADJ. trim-pot.
(1) OFFSET RANGE switch
Toggle switch for selecting the OFFSET range, x0.1 or x1.
(2) OFFSET potentiometer
Potentiometer for compensating a DC OFFSET.
(3) ZERO ADJ. trim-pot
Trim-pot for setting the ZERO baseline for the OFFSET.
Trim-pots for compensating amplifier offsets. If the baseline is not zero even if the
input is grounded and the OFFSET potentiometer is in 0 position, this offset can be
compensated using the ZERO ADJ. trim-pot. Compensation procedure:
 Set the input switches to OFF to ground the inputs, and set the HIGH PASS
FILTER to 100 Hz.
 Set the GAIN range switch to 10 and adjust the baseline to zero using the ZERO
ADJ. trim-pot.
 Switch the GAIN factor switch to all positions and readjust to zero if necessary.
Note: The overall OFFSET compensation is the product of the reading of both controls, range
switch and potentiometer.
Important: The offset compensation works only if the HIGH PASS FILTER switch is set to
DC. If the HIGH PASS FILTER is used, the OFFSET control is disabled.
(4) GAIN switch
6-position rotary switch for setting the amplification factor (GAIN) of the signal
(10, 100, 1k, 2.5k, 5k and 10k).
(5) LOW PASS FILTER (Hz) switch
6-position rotary switch for setting the corner frequencies of the single pole
LOW PASS FILTER: 50, 100, 1k, 3k, 5k, 8k Hz.
Note: By combining HIGH- and LOW PASS FILTER, a filter with bandpass characteristic
can be implemented easily.

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(6) NOTCH filter switch (option)
Switch for enabling (ON) or disabling (OFF) the optional NOTCH filter.
(7) OUT connector
BNC connector providing the conditioned signal.
(8, 9) – IN, + IN connector
BNC connectors for connecting the input signal. The inputs can be used in single
ended or differential configuration. In differential configuration the signal which is
connected to –IN is subtracted from the signal that is connected to +IN.
Note: If only one input is used (single ended configuration) the other should be grounded to
avoid coupling of noise (see also 10 and 11).
(10, 11) input switches
ON / OFF toggle switches for grounding the BNC connectors 8and 9. In OFF
position the inputs are grounded.
(12) HIGH PASS FILTER (Hz)switch
6-position rotary switch for setting the corner frequencies of the single pole
HIGH PASS FILTER: DC, 0.1, 1, 100, 300, 600 Hz.
In DC position the HIGH PASS FILTER is disabled.
Note: By combining HIGH- and LOW PASS FILTER, a filter with bandpass characteristic
can be implemented easily.

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4. Literature
 Barmashenko, G., Eysel, U. T., & Mittmann, T. (2003). Changes in intracellular calcium
transients and LTP in the surround of visual cortex lesions in rats. Brain Res. 990, 120-
128.
 Boulton, A. A., Baker, G. B. & Vanderwolf, C. H. (eds.) (1990). Neurophysiological
Techniques, Basic Methods and Concepts. Humana Press, Clifton, New Jersey.
 Huemmeke, M., Eysel, U. T., & Mittmann, T. (2002). Metabotropic glutamate receptors
mediate expression of LTP in slices of rat visual cortex. Eur.J.Neurosci. 15, 1641-1645.
 Huemmeke, M., Eysel, U. T., & Mittmann, T. (2004). Lesion-induced enhancement of
LTP in rat visual cortex is mediated by NMDA receptors containing the NR2B subunit. J
Physiol 559 , 875-882.
 Schulz, D., Huston, J. P., Jezek, K., Haas, H. L., Roth-Harer, A., Selbach, O., & Luhmann,
H. J. (2002). Water maze performance, exploratory activity, inhibitory avoidance and
hippocampal plasticity in aged superior and inferior learners. Eur.J.Neurosci. 16, 2175-
2185.
 Kettenmann, H. & Grantyn, R. (eds.) (1992). Practical Electrophysiological Methods.
Wiley-Liss, New York
 Lalley, P.M., A.K. Moschovakis and U. Windhorst (1999) Electrical Activity of Individual
Neurons In Situ: Extra- and Intracellular Recording, in: U. Windhorst and H. Johansson
(eds.) Modern Techniques in Neuroscience Research, Springer, Berlin, New York
 Müller, Ch.M. (1992) Extra- and Intracellular Recording in the Slice, in: Kettenmann, H.
& Grantyn, R. (eds.) Practical Electro-physiological Methods, Wiley-Liss, New York
 Ogden, D. (ed.) (1992) Microelectrode Techniques - The Plymouth Workshop Handbook,
Second Edition, The Company of Biologists Ltd., Cambridge
 Seidenbecher, T. and H.C. Pape (2001) Contribution of intralaminar thalamic nuclei to
spike-and-wave-discharges during spontaneous seizures in a genetic rat model of absence
epilepsy, European Journal of Neuroscience, Vol. 13:1537-1546
 Windhorst, U. and H. Johansson (eds.) (1999) Modern Techniques in Neuroscience
Research, Springer, Berlin, Heidelberg, New York

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5. Technical Data
DPA-2FL
Input range: ±12 V; protected up to 15 V
Input impedance: 1 M, related to ground
Input capacitance: 30 pF
Noise: <5 µV rms @ full bandwidth (8 kHz) and gain 10k
OFFSET compensation: set by potentiometer, range x0.1 or x1, set by toggle switch
HIGH PASS FILTER: single pole, attenuation: -6 dB / octave, corner frequencies (Hz): DC;
0.1, 1, 100, 300, 600
LOW PASS FILTER: single pole, attenuation: -6 dB/octave, corner frequencies (Hz): 50,
100, 1k, 3k, 5k, 8
NOTCH FILTER: 50 Hz or 60 Hz
GAIN: rotary-switch 10, 100, 1k, 2.5k, 5k, 10k
Output: range: ±12 V into 1 k/ ±1 V into 50 
Size: front panel 12 HP (60.6 mm) x 3U (128,5 mm), 7” (175 mm) deep
EPMS-07 SYSTEM
Power requirements: 115/230 V AC, 60/50 Hz, fuse 2 A / 1 A, slow, 45-60 W (dependent
on the modules plugged in)
Dimensions: 19” rackmount cabinet, 3U high (1U = 1 ¾” = 44.45 mm)