OPERATING INSTRUCTIONS AND SYSTEM DESCRIPTION FOR
Contents
1. 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 by trained staff only General safety regulations for operating electrical devices are to be followed 2 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 with 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 3 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 4 HANDLING Please protect the device from moisture heat radiation and corrosive chemicals version 1 1 page 3 RS 01R User Manual 2 Introduction 2 1 Basic idea of Rs measurement The instrument is based on the2. the course of Pg and Cer at the oscilloscope With the potentiometers DAMP 3 Figure 1 and TIME BASE 14 Figure 1 adjust the shape of the Crr signal until it is as square as possible Details of the procedure are version 1 1 page 7 RS 01R User Manual shown in the following figures After adjustment the value at the display of the RS 01R corresponds to the series resistance in X XX kQ Notice Because of the measuring method and the background noise you always will see values of at least 10 to 20 Q even if no series resistance is present e g when using a cell model The BNC connector Rs 13 Figure 1 OUT provides a DC voltage proportional to the value of series resistance scaling 1V KQ As mentioned above the measurement can be started using a TTL signal fed into the BNC connector Rs IN TTL 12 Figure 1 at the front panel of the Rs box HI starts the measurement In principle after the measurement when the signal at TTL is low again or the switch is in the OFF position the stored Rs value is displayed continuously until the next measurement is started 6 Adjustment Procedure Using a Cell Model Example Important You can test the RS 01R only with a cell model that mimics the series resistance Upper lane signal of the potential electrode 200 mV DIV Lower lane signal of the current electrode 2 V DIV Time base for Figure 2 5 ms DIV Figure 2 signals without Rs box version 1
3. 1 page 8 RS 01R User Manual Time base for Figure 3 to Figure 9 100 us DIV PY m Figure 3 Current electrode greatly under compensated too low setting of TIME CONSTANT LA LA Figure 4 Current electrode slightly under compensated still too low setting of TIME CONSTANT version 1 1 page 9 RS 01R User Manual Figure 5 Current electrode over compensated too high setting of TIME CONSTANT Figure 6 Current electrode correctly compensated perfect setting of TIME CONSTANT version 1 1 page 10 RS 01R User Manual LA LA Figure 7 Current electrode correctly compensated but the delay is too high i e the setting of DAMP is too low y LA Figure 8 Current electrode correctly compensated but the delay is too low 1 e the setting of DAMP is too high version 1 1 page 11 RS 01R User Manual y Mm Figure 9 Current electrode correctly compensated the delay is good 1 e the setting of DAMP is perfect 7 Links for Additional Information http www npielectronic com content downloads RS_spaceclamp zip http www npielectronic com content downloads RS_Poster zip http www npielectronic com content downloads RS_and_C_measurement pdf 8 Appendix Series resistance measurement Poster presented at the 29th GOTTINGEN NEUROBIOLOGY CONFERENCE 2003 see http www npielectronic com content downloads RS_Poster zip version 1 1 page 12
4. 9 rack mount cabinet and can be connected to every npi TURBO TEC amplifier using the supplied cable Modification of the amplifier is not required The current headstage is connected to the RS 01R with the 15 pole connector cable to CURRENT HEADSTAGE connector 11 Figure 1 The 15 pole connector of the Rs box 10 Figure 1 is connected to the CURRENT HEADSTAGE connector at the TEC amplifier Per x10 1 Figure 1 is connected to Pg x10 at the front panel of TEC and to an oscilloscope Ck at the front panel of the Rs box is connected to the other channel of the oscilloscope A power supply is not required Caution The voltage at Cg can be up to 150 V 5 Operation Rg measurement is done in CC mode of the amplifier If currently operating in VC mode and the MODE OF OPERATION switch at the RS 01R is set to AUTO the TEC amplifier is automatically set to CC mode and the same holding current needed for setting the holding potential in VC mode is applied to the cell Thus there should be only slightly changes in membrane potential when switching to Rs measurement in AUTO position As a Start point use a test pulse frequency of 3 kHz recommendation of Prof Conti Later the frequency can be adjusted if necessary Set the Rs MEAS mode switch 5 Figure 1 to CONT continuous or MAN manual Then make sure that the CURRENT RANGE switch is in the right position see 2 Figure 1 You will see a value at the display of the Rs box and
5. O P HOLD POTENTIAL INPUT O 0 o 0 CURRENT RAN 8 tay wegen g 3 5 E ES 28 55 k gt E E 5 8 POTENTIAL OUTPUT DIFFERENTIATOR 8 ME TVQ our Re INTY RS 071R npi O O O version 1 1 page 5 RS 01R User Manual In the following description of the front panel elements each element has a number that is related to that in Figure 1 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 Each control element has a label and frequently a calibration e g Per x10 mV 1 POTENTIAL INPUT Per x10 mV connector BNC connector for connecting the potential output potential electrode of the TEC amplifier 2 CURRENT RANGE switch optional 4 position switch for selecting the CURRENT RANGE If the TEC amplifier is equipped with a headstage with different current ranges the CURRENT RANGE selected at the RS 01R must be the same as the CURRENT RANGE selected at the headstage 3 DIFFERENTIATOR DAMP potentiometer Potentiometer for adjusting the damp factor of the PD controller 4 FREQUENCY potentiometer Potentiometer for setting the frequency of the test pulses range 2 kHz 5 kHz 5 Rs MEAS switch Switch to select the Rs measurement CONT Rs is measured continuously HOLD The last measurement of Rs is kept MAN Rs is me
6. asured until the switch is released 6 SERIES RESISTANCE kQ display LED showing the measured Rs in kQ 7 BIAS trim pot Trim pot to cancel the BIAS current 8 HOLD CURR potentiometer Potentiometer for setting the HOLDING CURRENT manually if 8 is in or position 9 MODE OF OPERATION switch 4 position switch for selecting the MODE OF OPERATION see also 8 He positive HOLDING CURRENT is applied me negative HOLDING CURRENT is applied OFF HOLDING CURRENT is disabled AUTO the RS 01R applies a HOLDING CURRENT as set at the TEC amplifier 10 CURRENT HEADSTAGE CONNECTOR TEC 15 pole connector for connecting the TEC amplifier see also chapter 4 version 1 1 page 6 RS 01R User Manual 11 CURRENT HEADSTAGE 15 pole connector for connecting the current headstage see also chapter 4 12 Rs IN TTL BNC connector to connect a TTL signal for remote operation HI Rs measurement on LOW Rs measurement off 13 Rs OUT BNC connector providing a voltage proportional to the series resistance scaling 1V kQ 14 TIME BASE potentiometer Potentiometer for setting the TIME BASE of the PD controller 15 POTENTIAL OUTPUT Cg x10 mV connector BNC connector providing the potential at the current electrode Caution The voltage at Cer can be up to 150 V 16 POTENTIAL OUTPUT Per x10 mV connector BNC connector providing the potential at the voltage electrode 4 Connections The RS 01R comes in a 1
7. injection of symmetrical current pulses of 10 uA and a few kHz around the holding or resting potential of the cell The membrane potential deviation that appears on the positive slope of the pulse is proportional to Rs and is measured using high precision sample and hold circuits controlled by a timing unit that is synchronized from the injection pulses applied Rs is displayed on a digital meter with a resolution of 104 and can be also stored on a computer Rs measurement can be started manually or through a TTL input After the measurement the stored Rs value is displayed continuously until the next measurement is started Therefore measurement can be automated easily using standard lab software 2 2 Solution The instrument is based on the injection of symmetrical current pulses of 10 microamperes and a few kHz around the holding or resting potential of the cell The membrane potential deviation that appears on the positive slope of the pulse is proportional to Rs and is measured using high precision sample and hold circuits controlled by a timing unit that is synchronized from the injection pulses applied The Rs measurement can be started manually or through a TTL input After the measurement the stored Rs value is displayed continuously until the next measurement is started To avoid jumps in the membrane potential a holding current can be set manually or the current supplied by the TEC system is applied automatically from a sample and hold circ
8. mae Instruments for the Life Sciences OPERATING INSTRUCTIONS AND SYSTEM DESCRIPTION FOR THE RS 01R INSTRUMENT FOR MEASURING SERIES RESISTANCE IN TEVC RECORDINGS VERSION 1 1 npi 2006 npi electronic GmbH Hauptstrasse 96 D 71732 Tamm Germany Phone 49 0 7141 9730230 Fax 49 0 7141 9730240 e mail support npielectronic com http www npielectronic com RS 01R User Manual Table of Contents 1 Satety Resulationss es 3 2 VIREO CIC TIO A O AS OA 4 2 1 Basic idea of Rs Measurement oooonococoncccconononanonononoconononannnnnnononeccononnananononenccnoninnananiness 4 AA O amp EE fice tae talc edn decide dat 4 DES Mee WGC Els AA O O A A A a aata 4 3 Description of the Front Panel ssc ccchsiscarsssisetsisshecthass cease dundecaxchanacaa Rias 5 4s Connections Gai A A IEA 7 Di MODE TAO N itr Sealine dd Set cuts kd ecm uns Mena a ella hel aly aid 7 6 Adjustment Procedure Using a Cell Model Example oooonccnnncciococococonocononononoconoconaninnnoos 8 7 Links for Additional Information siria 12 A O 12 version 1 1 page 2 RS 01R User Manual 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
9. uit The Rg measurement system can be used for automated procedures using standard lab software One problem is the shape of the injected current stimulus signal It should be as square as possible but in practice there are always parasitic capacitances leading to distortion of the current Thus the stimulus signal is conditioned in order to get an optimal square shape We use a PD proportional differential controller Time constant and damping of the controller are adjustable to a certain extend Depending on the frequency a constant measurement window for two sample and hold amplifiers is created and the time course of Pg is saved The first measuring point represents the baseline and the second the value of Pry just before the increase caused by the capacitance of the cell or model cell respectively The difference of the values of these two measurements corresponds to the value of Rs 2 3 Cell Model The properties of the Rg measurement are tested best using a cell model that mimics not only electrode resistance membrane resistance and membrane capacitance but also the series resistance see also A cell model with series resistance is available on request version 1 1 page 4 RS 01R User Manual 3 Description of the Front Panel Figure 1 RS 01 R front panel view the numbers are related to those in the text below HEADSIAGE CONNECTOR TEC eoocr000 MODE OF OPERATON HOLD eu FREQUENCY Rs 3 CONT SERIES RESISTANCE k
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