Metal Electrode Meter

Metal Electrode Meter

INSTRUCTION MANUAL FOR Metal Electrode Meter MODEL 2900 Serial # Date PO Box 850 Carlsborg, WA 98324 U.S.A. 360-683-8300 800-426-1306 FAX: 360-683-3525 http://www.a-msystems.com Version 3.0 April 2004

Contents General Description... 1 Instrument Features... 1 Controls and Connectors... 2 Operating Instructions... 3 Typical Set-Up Procedure... 3 Safety considerations... 6 Problem Solving... 6 Calibration Procedures... 6 Specifications... 7 Warranty and Service... 9 Each Metal Electrode Meter is delivered complete with: Power Supply Rack Mount Hardware Instruction Manual Input Cable Adjustment tool NOTE This instrument is not intended for clinical measurements using human subjects. does not assume responsibility for injury or damage due to the misuse of this instrument.

General Description Instrument Features The Model 2900 Metal Electrode Meter is designed to quickly measure the impedance of metal microelectrodes. Impedance is an important predictor of the electrode s recording and stimulating properties. The Model 2900 Metal Electrode Meter uses an oscillating small current source to measure the electrical properties of metal electrodes. A default 1kHz, 100nA signal is applied to the electrode. A microprocessor-controlled measurement is made and the resulting value of impedance is displayed on a digital meter for easy reading. The frequency and/or current of the test oscillating signal can be adjusted by the front panel controls if desired by the user. The Model 2900 Metal Electrode Meter can measure electrode impedances from 1 kohms to 20 MegOhms. 1

Controls and Connectors DISPLAY / MODE: Various messages, as well as the actual electrode impedance, will be legible on the DISPLAY. This pushbutton switch controls the MODE the unit is operating in. Upon powering on, the unit will enter the AUTOmatic mode, as indicated by the word AUTO in the display. Depressing the button once will switch the unit unto manual mode, where the user can set the test signal FREQUENCY, CURRENT, and the unit s GAIN sensitivity by rotating the CONTROL knob. Care needs to be used in modifying this setting to ensure maximal gain without signal saturation. CONTROL: This knob adjusts the value of the test signal s frequency or current, or the meter s gain, depending on the setting of MODE. CALIBRATE: The test signal can be monitored at this BNC connector. If the signal is exhibiting high frequency oscillations, then the small adjustment screw should be turned until the oscillations are eliminated. INPUT & GND: The Model 2900 comes with a dual banana to dual micro-clip cable. The banana plug with the ground tag should be connected to the GND input connector, and the black micro-clip should be connected to a reference wire. The red micro-clip, which should be connected to the electrode, will be connected to the red INPUT connector. POWER This switch turns the Metal Electrode R/C Meter ON or OFF. Rear Panel POWER INPUT This jack connects the DC power source to R/C Electrode Meter. The DC supply provides +15V, -15V, and +5V. 2

Operating Instructions AUTOmatic Mode This is a generalized procedure for setting up the Model 2900 Metal Electrode Meter for measuring electrode characteristics. Portions of this procedure may need to be modified for your specific application. 1. Fill a beaker with physiological saline (or the solution in which the tissue will be bathed). The solution should have the same temperature and ionic strength as that in which your experiments will be made. 2. Connect the supplied dual banana to micro-clip cable to the INPUT and GND connector on the front panel. Make sure the ground tab on the dual banana plug is plugged into the black GND connector on the front panel. If you use a different cable than the one supplied with the Model 2900 than you may have to re-calibrate the instrument (See cable calibration). 3. Attach a reference wire (generally an Ag/AgCl reference electrode) to the black micro clip, and place the end into the saline within the beaker. 4. Dip the electrode to be measured and the reference electrode into the beaker of physiological saline solution Note: immerse the metal microelectrode to approximately the same depth as will be used during the experiment. 5. Turn the POWER switch to ON and allow the Model 2900 to warm up for 1 minute. 6. Connect the red micro-clip to the electrode to be measured. 7. The unit will begin to measure the impedance of the electrode. When complete, the display will settle on the final value. 8. If the value of impedance is below 1kΩ, the meter will display 0kΩ. If the impedance is over 20MegΩ, the meter will display OVERRANGE. 10. MODE This pushbutton switch controls the MODE the unit is operating in. Upon powering on, the unit will enter the AUTOmatic mode, as indicated by the word AUTO in the display. In AUTO mode, the unit will automatically search for the optimal gain required to read the electrode s impedance. Depressing the button once will switch the unit unto manual mode, where the first setting that can be adjusted is FREQUENCY. Rotating the CONTROL knob will modify the test signal s frequency. Depressing the button again will display the next setting that can be adjusted: CURRENT. Rotating the CONTROL knob will modify the test signal s current setting. Depressing the button again will display the next setting that can be adjusted: GAIN. 3

Operating Instructions Manual Mode This is a generalized procedure for setting up the Model 2900 Metal Electrode Meter for measuring electrode characteristics. Portions of this procedure may need to be modified for your specific application. 1. Fill a beaker with physiological saline (or the solution in which the tissue will be bathed). The solution should have the same temperature and ionic strength as that in which your experiments will be made. 2. Connect the supplied dual banana to micro-clip cable to the INPUT and GND connector on the front panel. Make sure the ground tab on the dual banana plug is plugged into the black GND connector on the front panel. If you use a different cable than the one supplied with the Model 2900 than you may have to re-calibrate the instrument (See cable calibration). 3. Attach a reference wire (generally an Ag/AgCl reference electrode) to the black micro clip, and place the end into the saline within the beaker. 4. Dip the electrode to be measured and the reference electrode into the beaker of physiological saline solution Note: immerse the metal microelectrode to approximately the same depth as will be used during the experiment. 5. Turn the POWER switch to ON and allow the Model 2900 to warm up for 1 minute. 6. Connect the red micro-clip to the electrode to be measured. 7. Depress MODE once. The meter will enter the manual mode, and display the instruction SET FREQUENCY. 8. Rotating the CONTROL knob will cycle through the available signal frequencies: 200Hz, 400Hz, 500Hz, 800Hz, 1.0kHz, 2.0kHz, 5.0kHz, and 10kHz. Pressing MODE again will enter the selected frequency, and then the unt will display the instruction SET CURRENT. 9. Rotating the CONTROL knob will cycle through the available test signal current levels: 10nA, 20nA, 50nA, 100nA, Pressing MODE again will enter the selected current level, and then the unt will display the GAIN display. 10. In this display, the bar graph indicates the sensitivity of the unit. The CONTROL knob should be rotated until the bar graph extends to within 5 lines (one block) of the vertical tick mark in the upper line. If the bar graph extends significantly beyond the tick mark, then the test signal is not within the tolerance of the internal A/D, and the measurement is not accurate. Similarly, if the bar is significantly less than the tick mark, than the sensitivity of the unit is too low, and the measurement is inaccurate. 4

11. Depress MODE once more. The meter will return to the AUTO mode, but the current and frequency used will be those values set by the user. One way to return to AUTO mode with the unit s defaults of 1.0kHz and 100nA test signal, the power can be turned off and on. 5

Safety considerations Removal of the cover will expose the electronic components. Capacitors inside the instrument may still be electrically charged even when the instrument has been disconnected from all power sources. Problem Solving If the Model 2900 does not function properly, consult the following list of suggested solutions to the most common problems. If you need further assistance, please contact technical support at Problem Values keep changing Cause / Solution There is most likely too much noise in your setup. Try turning off unnecessary equipment. Shield the metal microelectrode, reference electrode, input cables and the Model 2900 from external noise. Increase the signal size by entering manual mode and changing Frequency, Current, and or Sensitivity. The meter always reads over-range The unit is most likely out of calibration or you have a broken connection to your electrode. Try re-calibrating the unit. Cable calibration Controls Inputs / Observations Adjust / Check Power: On Display: AUTO Connect an input cable and a resistor of similar value of the electrodes to be measured across the inputs. Connect a BNC cable to the BNC connector and to an oscilloscope. Observe Oscilloscope. Adjust CAL screw until waveform begins to oscillate. Then back off (turn CAL screw counterclockwise) one quarter turn. 6

Specifications Input Impedance 10 13 Ω 1pF Internal signal source Frequency (AUTO default = bold) Amplitude 200Hz, 400Hz, 500Hz, 800Hz, 1.0kHz, 2.0kHz, 5.0kHz, and 10kHz. Sine wave 10nA, 20nA, 50nA, 100nA, Meter Output Impedance 1 kω - 20 MΩ ; 2 significant digits Power +15 Vdc 50 ma - 15 Vdc 50 ma + 5 Vdc 100 ma DC voltages are used in the METER, so it can be used inside a Faraday cage Physical Dimensions Width Height Depth Weight 8.45 inches (21.46cm) 2.55 inches (6.477 cm) 3.95 inches (10 cm) 12 lbs. 7

Model 8750 Remote power supply Input: EING Output +15 Vdc 2.0 A 100-240 VAC 50/60 Hz, 1.0 A MAX. -15 Vdc 0.5 A +5 Vdc 3.0 A 36 W Max 8

Warranty and Service What does this warranty cover? warrants to the Purchaser that the Instrument, excluding cables, Headstage Probes and any other accessories shipped with the Instrument, (hereafter the hardware ) is free from defects in workmanship or material under normal use and service for the period of one (1) year. This warranty commences on the date of delivery of the hardware to the Purchaser. What are the obligations of under this warranty? During the warranty period, agrees to repair or replace, at its sole option, without charge to the Purchaser, any defective component part of the hardware. To obtain warranty service, the Purchaser must return the hardware to or an authorized distributor in an adequate shipping container. Any postage, shipping and insurance charges incurred in shipping the hardware to must be prepaid by the Purchaser and all risk for the hardware shall remain with purchaser until such time as A-M Systems, Inc. takes receipt of the hardware. Upon receipt, will promptly repair or replace the defective unit, and then return the hardware to the Purchaser, postage, shipping, and insurance prepaid. may use reconditioned or like new parts or units at its sole option, when repairing any hardware. Repaired products shall carry the same amount of outstanding warranty as from original purchase, or ninety (90) days which ever is greater. Any claim under the warranty must include a dated proof of purchase of the hardware covered by this warranty. In any event, liability for defective hardware is limited to repairing or replacing the hardware. What is not covered by this warranty? This warranty is contingent upon proper use and maintenance of the hardware by the Purchaser and does not cover batteries. Neglect, misuse whether intentional or otherwise, tampering with or altering the hardware, damage caused by accident, damage caused by unusual physical, electrical, chemical, or electromechanical stress, damage caused by failure of electrical power, or damage caused during transportation are not covered by this warranty. Products may not be returned to for service, whether under warranty or otherwise, which are contaminated by infectious agents, radioactive compounds or other materials constituting a health hazard to employees of What are the limits of liability for under this warranty? shall not be liable for loss of data, profits or savings, or any special, incidental, consequential, indirect or other similar damages arising from breach of contract, negligence, or other legal action even if the company or its agent has been advised of the possibility of such damages, or for any claim brought against you by another party. THIS EQUIPMENT IS NOT INTENDED FOR CLINICAL MEASUREMENTS USING HUMAN SUBJECTS. A-M SYSTEMS, INC. DOES NOT ASSUME RESPONSIBILITY FOR INJURY OR DAMAGE DUE TO MISUSE OF THIS EQUIPMENT. Jurisdictions vary with regard to the enforceability of provisions excluding or limiting liability for incidental or consequential damages. Check the provision of your local jurisdiction to find out whether the above exclusion applies to you. This warranty allocates risks of product failure between the Purchaser and hardware pricing reflects this allocation of risk and the limitations of liability contained in this warranty. The warranty set forth above is in lieu of all other express warranties, whether oral or written. The agents, employees, distributors, and dealers of are not authorized to make modifications to this warranty, or additional warranties binding on the company. Accordingly, additional statements such as dealer advertising or presentations, whether oral or written, do not constitute warranties by and should not be relied upon. This warranty gives you specific legal rights. You may also have other rights which vary from one jurisdiction to another. 9