Potentiostat PS-705

Potentiostat PS-705
TECHNICAL
MANUAL
MODEL PS-705
ELCHEMA
P.O. Box 5067
Potsdam, New York 13676
TeL: (315) 268-1605
FAX: (315)268-1709
TABLE OF CONTENTS
1. INTRODUCTION .... ...... ...... ...... ............ ....... .......... ......... .... .......... ........... .....
2
2. SPECIFICATIONS .........................................................................................
3
3. CONTROLS ..................................................................................................... 6
3.1. Front Panel
6
6
Input I Output Connectors
~~~
9
Diode Indicators
12
Other Controls
13
3.2. Back Panel
16
3.3. Faraday Cage (side panel)
19
3.4. Faraday Cage (internal panel)
21
4. INITIAL
4.1.
4.2.
4.3.
4.4.
CHECKS ... ......... ......... ................... ... .... ............. .............................
Inspection
Precautions
Grounding and Environmental Transients
Thermal Sensitivity
23
23
23
24
24
5. INSTALLATION ............................................................................................
5 .1. Unpacking
5.2. Initial Set-up
5.3. Power-On Checks
5.4. Test Experiment with real cell ON
25
25
25
31
32
6. ELECTRICAL CIRCUITS ....... ....... ..... .................................... .......... ..........
34
7. SERVICING NOTES ..................................................................................... 36
8. WARRANTY, SHIPPING DAMAGE, GENERAL ................................
37
1. INTRODUCTION
The ELCHEMA Potentiostat, Model PS-705, is designed to maintain a known
potential difference between two output connectors, WE and REF (the Working
Electrode and Reference Electrode, respectively), regardless of changes in either the
resistance or capacitance of the external circuit connected to these points by the user. The
dynamic capabilities of the Potentiostat are designed to allow controlling experiments with
fast changing potential programs, as well as to achieve a high degree of the system
stability. The Model PS-705 with its rise time of 200 ns is one of the fastest potentiostat
on the market and it allows the user to scan potential with scan rates up to 800 kV/s
under favourable conditions. To achieve this high a scan rate, electrodes with very low
capacitance have to be used. Recommended are electrodes with capacitance in the range
from few pF to 200 pF. The resistance of electrodes and connections should also be kept
as low as possible.
For the measurement set-up with PS-705, we recommend a fast Program
Waveform Generator (Model FG-206F) and Digital Oscilloscope (Cat. # OSC-223). For
slower transients and scan rates, a high precision 16-bit Data Acquisition System (DAQ616) for ruM PC/AT compatible microcomputers and VOLTSCAN real-time data.
acquisition software (SFT-916) can be used. Further data processing, graphing and
spreadsheet reporting can be done with Master Windows 3.2 (SFT-930).
2
2. SPECIFICATIONS
Current Measurement
Maximum Current: ...........................................
Ranges: ..............................................................
Resolution: .......... .............................................
Overload Signal: .... ...... ....... ............ ........ ..........
300 rnA
100 rnA to 10 nA
10 pA
ca. 3 times the nominal current range
Potential Control
Range: ............................................................... .
Applied Potential Accuracy: .......................... .
Potential Program Source: ............................ ..
Potential Program Input Impedance: .......... ..
-10 V to +10 V
0.1 % of reading + 0.15 % FS
-10 V to +10 V (external)
1 Mohm, differential input
(shield referenced to ground through a
1 Mohm resistor)
Maximum Scan Rate: ..................................... .. 500 kV/s (800 kV/s, typical)
Overload Signal: ............................................. .. -10.3 V, +10.3 V (approx.)
.Other Measurements
Galvanostatic Measurements
Program Voltage Translation .............. 1 Volt per nominal current range
Potential Measurement ........................ -10 V to + 10 V
EMF (Electromotive Force)
Input Impedance .................................. > 1012 ohm
(set CELL on, CONTROL off)
Measurement Range ............................ ±1O V (E-out)
Corrections
IR Potential Drop ............................................. positive feedback
3
Recorder Output
Potential: ............................................................ 1 V per Volt
Potential Sign Convention: ........... ..... more positive potentials for more
anodic currents
Accuracy: .............................................. 0.1 % of reading + 0.15 % FS
Output Range: ..................................... -10 V to +10 V
Load Resistance: ................................. > 500 ohm
Current: ...... .......... ....... ......... ..................... ......... 1 V per nominal current range (gain xl),
2 V per nominal current range (gain x2),
5 V per nominal current range (gain xS)
Sign Convention: .......... .............. ......... anodic currents positive
(IUPAC Stockholm Convention)
Accuracy: .............................................. 0.1 % of reading + 0.15 % FS
Output Range: ..... ....... ................ ......... ±1 V at gain xl, ±3 V max.,
±2 V at gain x2, ±6 V max.,
±5 V at gain xS, ±1O V max.,
Load Resistance: ... .............................. > 500 ohm
Electrical Characteristics
Input Impedance: .... ........................... .............. > 10 12 ohm
Output Impedance: ................................... ....... < 0.2 ohm
Offset Voltage: ................ .................... .............. < 80 u V
Slew Rate: ............................. ............................ 30 V /j.ls
Rise Time: ......................................... ................ 200 ns
Check with filters OFF, FAST mode, PS control,
1 kohm resistive load (e.g. internal dummy cell),
1 rnA range, 10% to 90% of full signal, 1 V step
Compliance Voltage: ................ ....... ................ ±15 V
Operating Parameters
Power Supply: ................................................... 1101220 V
50 - 60 Hz, 100 W
Dimensions: ....................................................... 6.5 H x 17 W x 16.5 D, inch
Faraday Cage: ...................................... 16 H x 12 W x 10 D, inch
4
Options
FG-206F
OSC-223
DAQ-616
SFf-916
SFf-930
RTC-101
Electrodes
Fast Program Waveform Generator
Digital Oscilloscope
16 bit Data Conversion Card
VOLTS CAN 3.8 Real-Time Data Acqnisition Software with
wave form generation
Master Windows Data Processing and Graphics Software
General Purpose ROTACELL Electrochemical Cell System
Wide selection of Working Electrodes, Reference and Counter
Electrodes including microelectrodes and quartz crystal
piezoelectrodes
5
3. CONTROLS
The front and back view of the Instrument are presented in Figures 1 and 2,
respectively. For the front panel, the controls are described in the following order:
Input I Output Connectors
Switches
Diode Indicators
Other Controls
Read this Chapter carefully since it provides you with a full and systematic description
of the functionality and limitations of all features and facilities available in the instrument.
For exemplary schematics of connections and experimental measurement set-up, refer to
the Chapter 5.
3.1 FRONT PANEL
Input / Output Connectors
1. PROGRAM-IN
BNC input socket to receive a potential program waveform from a fast
function generafor (e.g., ELCHEMA Model FG-206F) or a digital-toanalog 'converter (e.g., DAQ-6l6). This socket is identical (and
electrically shorted) to the P-IN BNC socket provided for your
convenience on the back panel of the instrument (if you do not change
very often the program voltage source it may be more convenient to use
the back panel socket p·IN and keep all the cable connections on the
back). The PROGRAM-IN input is internally connected to a high speed
6
differential amplifier. This input is symmetrical, i.e. you can change the
sign of the program voltage hy reversing the signal and guard lines (the
signal line is internally referenced to the analog ground of the potentiostat
through a 1 Mohm resistor and the guard line is also referenced to ground
through a 1 Mohm resistor). The PROGRAM-IN input is a noninverting input. This means that a +1000 mV program voltage (signal
line vs. guard) will set the potential of the working electrode to the value
E::: +1000 mV vs. a reference electrode (in potentiostatic mode), or force
a positive (anodic) current flow equal to the nominal current range (in
galvanostatic mode). Because of the high input impedance, hasicallyany
type of a generator or waveform programmer can he connected to the
PROGRAM-IN input. The input voltage range is from +10 V to -10 V
vs. a.c. ground. !<loating voltage sources will he referenced to ground
with 1 Mohm resistance mentioned above. Do not connect to the
program input any voltage sources which exceed the allowed potential
range from +15 V to -15 V liS. a.c. ground.
POTENTIAL output: BNC socket providing output voltage equal to the
potential E of the working electrode (measured with respect to the
potential of the reference electrode), Connect this socket to an external
recorder monitoring the changes in E. The load impedance should not he
lower than 2 kohm. This socket is identical (and electrically shorted) to
the E-OUT BNC socket provided for your convenience on the hack panel
of the instrument.
3. I-OUT
CURRENT output: BNC socket providing output voltage proportional
to the current flowing through the electrochemical cell (or dummy cell).
The output voltage of 1 V corresponds to the current equal to the
CURRENT RANGE selected. For example, if the selected CURRENT
RANGE is 10 rnA and the output voltage is +1 V, the current flowing is
+10 rnA (anodic), If, for the same CURRENT RANGE of 10 rnA, the
output voltage is -1 V, the current flowing is -10 rnA (cathodic), The
actual current is also displayed on the CURRENT panel meter. The
extended linearity of the I-OUT signal is from -3 V to +3 V. The load
impedance should not he lower than 2 kohm. This socket is identical
(and electrically shorted) to the I-OUT BNC socket provided for your
convenience on the hack panel of the instrument.
7
D
FIGURE 1. Front panel view of the Model PS-705 Potentiostat.
Switches
4. MODE
Toggle switch with two positions:
PS - potential control (Potentiostat) and
GS - current control (Galvanostat).
If the Galvanostat option is not installed, the potential control is retained
also in GS position.
5. CELL
CELL SELECTOR with two positions:
OFF (or: DUMMY CELL) - In this posItIOn, an internal 1 kohm
precision resistor is connected to simulate the electrochemical cell. (The
resistor is connected between the WE' and CE' inputs of the potentiostat
circuitry, and CE' is shorted to the REF' input. The BNC sockets on the
front panel: REF, WE, and CE, are disconnected.) Use 1 rnA
CURRENT RANGE to work with dummy cell.
ON (or: EXTERNAL) - All three BNC sockets: WE, CE, and REF, are
connected to internal circuitry to allow for a full potential or current
control according to the PS/GS mode. Make sure the working electrode,
reference electrode, and counter electrode are immersed in the electrolyte
solution and properly connected to the potentiostat before you switch the
EXTERNAL CELL on. If any of the overload diodes is activated, switch
the cell OFF immediately (connect back to DUNlMY CELL) and check
the connections.
V6.
CONTROL
Two position toggle or pushbutton switch to tum the potentiostatic or
galvanostatic control ON and OFF:
OFF - the output of the power amplifier is disconnected from the CE
socket, while WE and REF inputs to the internal circuitry are connected
according to the CELL switch selection, i.e. to the dummy cell (when
CELL switch is in the OFF position), or to the WE and REF sockets on
the inside panel of the Faraday Cage (when CELL switch is the ON
position). With CELL ON and CONTROL OFF, you can perform
measurements of the rest potential, corrosion potential, or EMF. The
Working and Reference Electrodes must be connected to the tip banana
jacks WE and REF, respectively. Since the input resistance of the
measuring circuitry is higher than 10 12 ohms, the potential measurements
for virtually any type of electrodes can be accomplished, even for those
9
with very high impedance.
ON - all three electrode inputs (WE, REF, and CE) are connected to the
internal control system and the instrument controls either the potential (in
PS mode), or current (in GS mode). The control is imposed on the
external electrochemical cell when the CELL switch is in the ON
position, otherwise the control is imposed on the internal dummy cell (10
kohm resistor).
7. PROGRAM
Toggle switch for the program voltage source connected to the
I PROGRAM-IN BNC input socket, with two positions:
I ON - potential waveform applied to BNC socket marked PROGRAM-IN
is presented to the program input of the summing amplifier.
I
OFF -zero Volts is applied to the program input of the summing
amplifier.
~
8. RANGE
CURRENT RANGE selector: Eight position rotary switch for current
range selection, from 100 rnA to 10 nA. The range selected is indicated
by lite diodes. For each range, the extended linearity from -300% to
+300% of the range value can be utilized.
9. GAIN
Three position toggle switch to select gain for the recorder output signal
I-OUT. The gains are: 1,2, and 5.
% 10.
SPEED
Rotary switch with five positions allowing to select appropriate frequency
compensation for the given electrochemical cell. Usually, the position 2
or 3 should work best. Set this position of the SPEED control unless a
better stability and less noise is found at other positions. For special.
cells, it is advised to observe on a digital oscilloscope the potentiostatj
response to a step function to determine the best selection of the SPEED
control. Too high a speed would manifest itself by the appearance of
overshoots, while too slow speed would cause a slow settling. In general,·
the system will be more stable on less sensitive current ranges and at a
lower gain. If oscillations are encountered (blinking red indicator in the
CURRENT RANGE section and/or extensive noise at the I.;OUT recorder
output), immediately turn the CELL switch off. Turning to a less
sensitive current range, e.g. 100 rnA, and reducing the gain to xl may
( also help. For low current ranges,"we recommend to use the output filter
and gain xl to achieve higher stability of the system.
10
FAST - Minimal frequency compensation is employed, so the potentiostat
may react with an overshoot (for a step excitation), or even oscillate, for
potential steps with fast rise times, or pure capacitive loads. (Avoid using
FAST settings for IR-drop compensation.)
SLOW - Small frequency compensation is used to reduce overshoots and
prevent oscillations while still maintaining very fast response. For slower
scan rates and lower currents measured, use input and output filters to
reduce noise, if any.
11. INPUT FILTER SELECTOR
Six position rotary switch for selecting the time constant of an input filter
installed on the program input amplifier (external potential source C).
The time constants are as follows:
FILTER
POSITION
LED
TIME CONSTANT
#
ms
0
1
2
3
4
5
none
1
2
3
4
5
Filter OFF
0.002
0.02
0.2
0.7
2
This filter is designed for cyclic voltammetry with scan rates up to 1
kV/s. For faster measurements, the input filter should be either turned
OFF or in the position 1.
\
11
12. OUTPUT FILTER SELECTOR
Six position rotary switch for selecting the time constant of an output
filter installed on the current amplifier. The time constants are as
follows:
FILTER
POSITION
LED
#
TIME CONSTANT
0
none
1
1
2
3
2
3
4
4
5
5
Filter OFF
3
100
250
600
1000
ms
This filter is designed for slower scan cyclic voltammetry with scan rates
up to 500 mV Is. For faster measurements, the output filter should be
turned OFF. Slower scan rates and lower current ranges usually require
higher time constants. Too high a time constant may affect not only the
high frequency noise but also the signal itself. Check always if the
general shape of the i-E or i-t curve recorded remains unchanged after
selecting the higher time constant.
Diode Indicators
13. POTENTIAL OVERLOAD
Red LED activated when the measured potential of the working electrode
(vs. reference electrode) exceeds the default potential range: -10.5 V to
+10.5 V).
14. CELL INDICATOR
Yellow LED indicating if the external electrochemical CELL is ON.
15. CONTROL INDICATOR
Red LED indicating if the CONTROL is applied or not to the load (an
12
\
,
external electrochemical cell or an internal dummy cell).
16. CURRENT OVERLOAD
Red LED activated when the measured current exceeds approximately 3
times the actual current range.
17. CURRENT RANGE INDICATORS
Green LED's indicating the CURRENT RANGE selection.
18. SPEED INDICATORS
Green LED's indicating the frequency compensation (SPEED) selection.
19. INPUT FILTER INDICATORS
Green LED's indicating the input filter selection.
20. OUTPUT FILTER INDICATORS
Green LED's indicating the output filter selection.
21. IR COMPo INDICATOR
Red LED indicating if the IR COMPENSATION is turned ON.
22. POWER INDICATOR
Red LED indicating if the AC power is ON.
Other Controls
23. IR
CO~IP.
SWITCH
Toggle switch with two positions:
OFF - IR compensation is turned OFF,
ON - IR compensation is turned ON. In this position, the ohmic
potential drop corresponding to the resistance set with the IR
compensation adjust potentiometer is being used to correct the potential
of working electrode.
13
24. IR COMPo ADJUST
Scaled multiturn potentiometer used to set the resistance for Ohmic
potential drop compensation. One full turn corresponds to 10 % of the
current measuring resistor. The maximum compensation is equivalent to
the value of the current measuring resistor (10 turns). The maximum
value of the solution resistance ~n to be compensated at the current
range iRANGE is given by the following formula:
with Run expressed in [ohm], and iRANGE expressed in [A].
Set the IR COMPo ADJUST potentiometer to a value slightly lower than
the measured value of the resistance of the solution between Working
Electrode and Reference Electrode. If this resistance is unknown, you
can still compensate for the Ohmic potential drop using the following
procedure:
(1)
Set the IR COMPo ADJUST potentiometer to 0 (zero).
(2)
Turn the IR CONIP. SWITCH to ON.
(3)
Slowly turn the IR COMPo ADJUST potentiometer clockwise
until oscillations of the current and potential begin. At this point,
the system is over-compensated. The beginning of oscillations
can be observed on the oscilloscope or XY-recorder as an
increased noise. Large oscillations are usually indicated by the
POTENTIAL and CURRENT OVERLOAD warning diodes.
Turn the dial back to a value just before the start of oscillations.
Sometimes it is safer to slightly under-compensate to achieve
greater stability of the system.
/
WARNING: When the system becomes unstable and begins to oscillate
due to the IR potential drop over-compensation, your Working Electrode
may be ruined by uncontrolled anodic or cathodic currents. Remember
that potentiostat is capable of outputting up to 15 V at 1 A current.
Often you can avoid IR compensation by minimizing the distance
between WE and REF electrodes, using Luggin capillary, and/or
increasing the conductance of the supporting electrolyte. If you
experience a noise problem with your electrochemical cell, do not use any
IR compensation. The uncompensated ohmic resistance actually stabilizes
>
14
the system.
25. POWER
Main power switch. Power is ON in position 1, and OFF in position O.
15
3.2. BACK PANEL
1. P-IN
PROGRAM INPUT BNC socket. This socket is identical (and
electrically shorted) to the PROGRAM-IN BNC socket located on the
front panel of the instrument. Connect this socket to the output of an
analog voltage source such as a ramp generator (e.g. ELCHEMA Model
FG-206F), Waveform Programer (e.g. ELCHEMA Model-706), or a D/A
Converter (e.g. our DAQ-616SC system). The P-IN input is internally
connected to a high speed differential amplifier.
This input is
symmetrical, i.e. you can change the sign of the program voltage by
reversing the signal and guard lines (the signal line is internally
referenced to the analog ground of the potentiostat through a 1 Mohm
resistor and the guard line is also referenced to ground through a 1 Mohm
resistor). The P-IN input is a non-inverting input. This means that a
+ 1000 mV program voltage (signal line vs. guard) will set the potential
of the working electrode to the value E ::::: + 1000 mV vs. a reference
electrode (in potentiostatic mode), or force a positive (anodic) current
flow equal to the nominal cnrrent range (in galvanostatic mode). Because
of the high input impedance, basically any type of a generator or
waveform programer can be connected to the P-IN input. The input
voltage range is from +10 V to -10 V vs. a.c. ground. Floating voltage
sources will be referenced to ground with 1 Mohm resistance mentioned
above. Do not connect to the program input any voltage sources which
exceed the allowed potential range from +15 V to -15 V vs. a.c. ground.
2. E-OUT
POTENTIAL output: BNC socket providing output voltage equal to the
potential E of the working electrode (measured with respect to the
potential of the reference electrode). Connect this socket to an external
recorder monitoring the changes in E. The load impedance should not be
lower than 2 kohm. This socket is identical (and electrically shorted) to
the E-OUT BNC socket provided for your convenience also on the front
panel of the instrument.
16
o
••
••
••
••
••
••
••
••
•
FIGURE 2. Back panel view of the Model PS-705 Potentiostat.
3. I-OUT
CURRENT output BNC socket providing output voltage proportional
to the current flowing through the electrochemical cell (or dummy cell).
The output voltage of 1 V corresponds to the current equal to the
CURRENT RANGE selected. For example, if the selected CURRENT
RANGE is 10 rnA and the output voltage is +1 V, the current flowing is
+10 rnA (anodic). If, for the same CURRENT RANGE of 10 rnA, the
output voltage is -1 V, the current flowing is -10 rnA (cathodic). The
actual current is also displayed on the CURRENT panel meter. The
extended linearity of the I-OUT signal is from -3 V to +3 V. The load
impedance should not be lower than 2 kohm. This socket is identical
(and electrically shorted) to the I-OUT BNC socket provided for your
convenience also on the front panel of the instrument
4-6. Cl, C2, C3
BNC sockets to be connected to the respective BNC socket on the side
panel of the Faraday Cage.
7. SPLY
6-pin audio-type socket for power SUPPLY lines to be connected with a
multiconductor cable (provided) to a similar 6-pin audio-type socket on
the back panel of the Potentiostat.
8. I/O
Standard female DB-25 socket for digital input/output communication.
It should be connected to tbe corresponding male DB-25 connector on the
side panel of tbe Faraday Cage.
9. GND
Black or brown isolated Banana socket connected to the analog ground
of the instrument circuitry. The analog ground is floating, i.e. it is not
connected directly to the instrument CHASSIS or to the power line
ground wire. You can connect externally the GND socket to the
instrument CHASSIS or analog ground of other instruments if necessary.
10. CHASSIS Banana socket shorted to the instrument chassis. The instrument chassis
is connected internally to the power line ground wire (a.c. ground).
11. POWER socket
HP type socket for A.c. power inlet. It will accept 110 V or 220 V, 50
to 60 Hz. If the 1101220 V switch is not set properly for your power
supply, turn the power to the instrument off, and change the position of
the 110/220 V selector to the appropriate position. Use power cords
18
supplied with the instrument. American, British, and European power
cords are available.
12. 110/220 V switch
Power line voltage selector. The switch is set to 110 V when shipped
within the USA, and 220 V, elsewhere. Check the position of this switch
before you connect power to the instrument.
WARNING: Make sure the power in the instrument is OFF
before you change the position of the 110/200 V switch.
13. FUSE
Power fuse. Use 250 V, 2 A slow melting fuse if replacement is
necessary.
WARNING: Make sure the power in the instrument is OFF,
and the power cord is disconnected from the instrument
before you replace the fuse.
3.3. Faraday Cage (side panel)
1. Cl
BNC socket to be connected to the corresponding socket on the front
panel of the potentiostat PS-705.
2. C2
BNC socket to be connected to the corresponding socket on the front
panel of the potentiostat PS-705.
3. C3
BNC socket to be connected to the corresponding socket on the front
panel of the potentiostat PS-705.
4. 110
Standard DB-25 male socket with proprietary communication bus lines
to be connected to a DB-25 female socket on the back panel of the
Potentiostat.
5. SPLY
6-pin aUdio-type socket for power SUPPLY lines to be connected with a
multiconductor cable marked PS-705 SPLY to a similar 6-pinaudio-type
socket on the back panel of the Potentiostat.
19
•••
••
••
...
...•
••
~----~------~
•
FIGURE 3. Side panel view of the Faraday Cage.
3.4. Faraday Cage (internal panel)
1. CE
COUNTER ELECTRODE: pin tip banana jack (red) for connection to
the counter electrode (auxiliary electrode) in the electrochemical cell.
Use short wires for connections to the electrochemical cell.
2. REF
REFERENCE ELECTRODE: pin tip bananajack (yellow) for connection
to the reference electrode (e.g., Saturated Calomel Electrode, SCE). The
input impedance is higher than 1012 ohm. Use as short a wire as possible.
3. WE
WORKING ELECTRODE: pin tip banana jack (blue) for connection to
the working electrode in the electrolytic cell. Use only short wires for
the connection.
4-7
Pin tip banana jacks for measurements with Electrochemical Quartz Crystal
Nanobalance system (refer to the EQCN Manual).
21
FIGURE 4. Inside panel view of the Faraday Cage.
4. INITIAL CHECKS
4.1. INSPECTION
After the instrument is unpacked, the instrument should be carefully inspected for
damage received in transit If any shipping damage is found, follow the procedure
outlined in the "Claim for Damage in Shipment" section at the end of this Manual.
4.2. PRECAUTIONS
Care should be taken when making any connections to the instrument. Use the
guidelines for maximum voltage at the inputs. There should be no signal applied to the
inputs when the instrument is turned off. The outputs should not be loaded. They can
only be eonnected to high input impedance devices such as plotters or oscilloseopes.
Use minimal force when putting on or taking off the BNC connections, otherwise
they might become loose. You should push the BNC forward when making a connection
or a disconnection in order to relieve the rotational tension on the BNC socket.
Operate the instrument in a cool and well ventilated environment.
Contact us in the event that any of our components do not operate properly. Our
components are marked with seals. Do NOT open and attempt to repair anything
yourself, otherwise your warranty agreement will be nullified.
23
4.3. GROUNDING AND ENVIRONMENTAL TRANSmNTS
It is very important to properly ground the instrument. Use only three-connector
power cords with ground connector connected to a good ground. If necessary, you can
additionally connect the instrument CHASSIS to a water pipe or other good ground
connector. Use a thick cable for grounding purposes. Do not connect analog ground of
the instrument (provided at the GND socket on the back panel) to the instrument
CHASSIS ground, unless you find it beneficial in reducing noise.
High level transients generated in power supply lines by heavy-duty electric
motors, lasers, arc welders, rf equipment, etc., may interfere with the normal operation of
the potentiostat. In such a case, placing a power line stabilizer in the lab may solve the
problem.
WARNING: Do not attach ground wires to a gas or heating pipe.
4.4. THERMAL SENSITIVITY
The instrument should be warmed up for 30 minutes in order to achieve the
greatest accuracy. However, for general purposes the improvement might be insignificant
and thus warmup could be omitted.
24
5. INSTALLATION
The operating instructions have been made short and simple but make sure they
are followed in this exact order. Bold letters indicate connections and controls on the
Potentiostat only.
5.1. Unpacking
Carefully remove all paper and tape used in shipping. Place instrument on a
convenient bench. Check the items against the packing list.
Make sure the POWER in the Potentiostat is OFF, and nothing is connected to
the instrument before you proceed with the Initial set-up procedure.
5.2. Initial set-up
(1)
Make sure the POWER in the Potentiostat, and in all other devices, is OFF, and
nothing is connected to the instrument.
(2)
Check the 110/220 V power voltage switch located in the back panel of the
instrument. Normally, tbis switch is set for 110 V operation (American) and 220
V (European). Change the position of this switch if necessary.
WARNING:
Befote you change the position of the 110/220 V switch, the
25
POWER switch must be set to OFF.
(3)
Attach the power cord to the back panel of the instrument. This is a standard
cable with HP type plug on one end (the instrument end) and American, British
or European plug on the otber end.
(4)
Attach the coaxial cables marked Cl, C2, and C3 to the coresponding BNC
sockets Cl, C2, and C3 on the front panel of the potentiostat and the side panel
of the Faraday Cage.
(5)
Attacb the multiconductor data communication cable with standard DB-25
connectors to the coresponding DB-25 female socket 110 on the back panel of the
potentiostat and DB-25 male socket on the side panel of the Faraday Cage.
(6)
Attach the supply cable with 7-pin audio connectors to the SPLY socket on the
back panel of the potentiostat and to the coresponding socket on the side panel
of the Faraday Cage.
(7)
Set the CELL switch to the OFF position. In this position, a DUMMY cell (1
kohm internal resistor) simulating the electrochemical cell is connected to the
inputs of the potentiostat circuitry.
(8)
Set the MODE switch to the PS position (potentiostat).
(9)
Set the PROGRAM switcheto the OFF position. This will supply zero Volts to
the potential program preamplifier.
(10)
Set the current RANGE rotary switch to 1 rnA. You will always use this range
with dummy cell since the internal dummy cell resistor is 1 kohm. This means
that for the potential changes in the range from -1 V to +1 V, the current flowing
through this resistor would be from -1 rnA to +1 mA (i.e. from -100% to +100%
of the nominal current range).
(11)
Set the IR COMPo SWITCH to OFF.
(12)
Connect the I-OUT BNC socket to the input of an analog recorder or a data
acquisition system (if you are using our DAQ-616 Data Conversion Card and
DAQ-617 Break-up Box, plug the BNC connector marked I to the I-OUT BNC
socket in the potentiostat).
26
(13)
Connect the E-OUT BNC socket to the input of an analog recorder or a data
acquisition system (if you are using our DAQ-616 Data Conversion Card and
DAQ-617 Break-up Box, plug the BNC connector marked E to the E-OUT BNC
socket in the potentiostat).
(14)
Connect BNC socket marked PROGRAM-IN to the output of a function
generator. The program waveform should be within +1000 mV to -1000 mY.
(If you are using DAQ-616/DAQ-617 Data Acquisition, the waveform may be
supplied by the computer. In this case, connect the BNC connector marked P
(for: PROGRAM) to the BNC socket for PROGRAM-IN input on the front panel
of the potentiostat. Follow instructions of the VOLTSCAN Version 3.7 manual.)
27
SPLY
o
I/o
FC
CELL
REF
WE
PS
CE
P
FG
XY
CELL
II
L_-.-------'
o
FIGURE Sa. Schematic diagram of an experimental set-up showing external connections
to the Potentiostat Model PS- 705. The potential (E) and current (I) outputs of the
Potentiostat (PS) are connected to an XV-recorder (XV). The program input (P) is
connected to the output (V-OUT) of a Waveform Generator FG (e.g., Model FG-20BF).
Other symbols: REF - Reference Electrode, WE - Working Electrode, CE - Counter
Electrode, SPLV - DC power supply cable, C1, C2, C3 - BNC coaxial cable connections.
SPLV
FC
o
CELL
REF
WE
PS
CE
o
CELL
FIGURE 5b. Schematic diagram of an experimental set-up showing external connections
to the Potentiostat Model PS-705 controlled by a Program Waveform Generator (e.g.
Model FG-506) and a Digital Oscilloscope (e.g. OSC-T22). The potential (E) and current
(I) outputs of the Potentiostat are connected to the inputs of channels A and B,
respectively, of the oscilloscope. The program input (P) is connected to the output (VOUT) of a Waveform Generator. Other symbols: PS - Potentiostat, FC - Faraday Cage,
FG - Waveform Generator, OSC - oscilloscope, REF - Reference Electrode, WE Working Electrode, CE - Counter Electrode, SPLY - DC power supply cable, C1, C2, C3 BNC coaxial cable connections.
SPLY
o
FC
CELL
PS
E
BB
CELL
DAQ
CPU
FIGURE Se. Schematic diagram of a computerized experimental set-up showing external
connections to the Potentiostat Model PS- 705. The potential (E) and current (I) outputs
of the Potentiostat are connected to a Data Acquisition Card DAQ (e.g. DAQ-616) through
a Break-up Box BB (DAQ-617). The program input (P) is connected to the output of a
Digital-to-Analog Converter which is a standard feature of the DAQ-616 system. Other
symbols: PS Potentiostat, FC - Faraday Cage, CPU - microcomputer, REF - Reference
Electrode, WE - Working Electrode, CE - Counter Electrode, SPLY - DC power supply
cable, C1, C2, C3 - BNC coaxial cable connections. (Note that unused inputs to the
DAQ-616 should be shorted).
5.3 Power-on checks
(15)
Set the potential channel sensitivity on your recorder to 2 V FS (full scale) and
the current channel sensitivity also to 2 V FS. Position the recorder pen in the
center of the chart using recorder Zero Offsets.
(16)
Tum the POWER switch in the potentiostat to ON (position 1).
(17)
Tum the POWER to the recorder ON.
(18)
On the potentiostat, panel meters should show now zero.
(19)
Tum the function generator ON and set the PROGRAM toggle switch on the
potentiostat to the ON position. The panel meters should show the same reading,
e.g.: if the applied potential (i.e. the voltage supplied to the PROGRAM input)
is +500 mY, the CURRENT panel meter should show 0.500 rnA. (From the
Ohm's law: 0.500 rnA x 1,000 ohm == 500 mV potential drop across 1 kohm
dummy cell resistor.) At the same time, the voltage output to the recorder on
potential channel should be +500 mY, and on current channel should be +500
mY.
Note that for fast changing potential and current values, front panel meters may
not show actual values because of the slow update rate.
(20)
Tum the PROGRAM input toggle switch to OFF.
Tum the CELL switch to OFF.
Tum the CONTROL switch to OFF.
Tum the POWER switch to OFF (position 0). Tum the recorder and the
function generator OFF.
This completes the initial checking procedure.
31
5.4. Test experiment with external cell ON
You are now ready to use the potentiostat for measurements. If you want to
perform a simple checking experiment, you can use, for example, a 10 ruM copper(II)
solution in 0.1 M HN0 3 • Program your waveform generator for sweep from +500 m V
vs. SCE to 0 mV and back to +500 mY. If you are using DAQ-616 Data Acquisition
System and VOLTS CAN 3.0 real-time data acquisition software, start VOLTS CAN by
typing: vv [ENTER], enter password if any, and go to PARAMETERS table. Set:
E1 = 500 mY,
E2 = 0 mY,
E3 = 500 mY,
E4 = 500 mV
SCANS: 3
t1 = 0,
t2 = 0,
t3 = 0,
vI = 100 mV/s,
v2 = 100 mV/s,
v3 = 100 mV/s,
~{:"J") h
LA.' 5
and VOLTSCAN will provide you with the PROGRAM wave you need
experiments.
III
your
Now, follow the important steps:
(1)
Check if the reference electrode is placed in the solution and connected to the
orange tip banana jack, marked REF, on the internal panel of the Faraday Cage.
(2)
Check if the counter electrode is placed in the solution and connected to the red
tip banana jack, marked CE, on the internal panel of the Faraday Cage.
(3)
Check if the working electrode is placed in the solution and connected to the
green tip banana jack, .marked WE, on the internal panel of the Faraday Cage.
(4)
Set the current RANGE on the potentiostat to 1 rnA FS.
(5)
Set the SPEED switch to the position 2 or 3.
(6)
Switch the CONTROL toggle to the ON position.
(7)
Apply an appropriate potential (the conditioning potential) to the program input
32
P-IN from your waveform generator or D/A converter. Set the PROGRAM
toggle switch to the ON position.
(8)
Set the CELL switch on your potentiostat to the ON (EXTERNAL cell) position.
(9)
Initiate the potential scan. (If you are using our automated data acquisition
system with VOLTSCAN 2 or 3, follow the instructions supplied in the
VOLTS CAN manual).
(10)
Change carefully the cathodic potential limit to more negative value until copper
deposition just begins to take place. On the voltanunogram you should be able
to observe an increase of the anodic peak due to the copper stripping.
(11)
Mter you finish an experiments, set:
CONTROL
CELL
OFF
OFF
and then:
PROGRAM
(12)
OFF
Turn the POWER to the instrument OFF.
33
6. ELECTRICAL CIRCUITS
34
PROGRAM
AOR
B
o
FIGURE 6. Simplified block diagram of an electronic circuit of a Potentiostat, Model PS~
705. PS ~ main control amplifier, WE ~ Working Electrode, CE ~ Counter Electrode, REF ~
. Reference Electrode, PROGRAM ~ program waveform amplifier.
7. SERVICING NOTES
In case of malfunction of the Potentio stat , Model PS-705, the unit may be
returned to the factory for service. It should be returned postpaid. Since the equipment
is guaranteed for one year, no charges for repair will be made for time and materials. The
guarantee does not cover misuse of the Model PS-705 or damage due to improper
handling or service. Before shipping the instrument, contact your local dealer or the
factory:
ELCHEMA
Customer Service
P.O. Box 5067
Potsdam, NY 13676
FAX: (315) 268-1709
Tel.:
(315) 268-1605
to receive the claim number.
36
WARRANTY
All our products are warranted against defects in material and workmanship for
one year from the date of shipment. Our obligation is limited to repairing or replacing
products which prove to be defective during the warranty period. We are not liable for
direct, indirect, special, incidental, consequential, or punitive damages of any kind from
any cause arising out of the sale, installation, service, or use of our instrumentation.
All products manufactured by ELCHEMA Company are thoroughly tested and
inspected before shipment. If ELCHEMA receives notice from the Buyer of any defects
during the warranty period, ELCHEMA shall, at its option, either repair or replace
hardware products which prove to be defective.
Limitation of Warranty
A. The Warranty shall not apply to defects resulting from:
1. Improper or inadequate maintenance by Buyer;
2. Unauthorized modification or misuse;
3. Operation in corrosive environment (including vapors, solids, and aggressive
solvents);
4. Operation outside the environmental specification of the product;
5. Improper site preparation and maintenance.
B. In the case of instruments not manufactured by ELCHEMA, the warranty of the
original manufacturer applies.
C. Expendable items, including but not limited to: glass items, reference electrodes,
valves, seals, solutions, fuses, light sources, O-rings, gaskets, and filters are excluded
from warranty.
THE WARRANTY SET FORTH IS EXCLUSIVE AND NO OTHER WARRANTY,
WHETHER WRITTEN OR ORAL, IS EXPRESSED OR IMPLIED. ELCHEMA
SPECIFICALL Y DISCLAIMS THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
37
For assistance of any ldnd, including help with instruments under warranty,
contact you ELCHEMA field office of instructions. Give full details of the difficulty and
include the instrument model and serial numbers. Service date and shipping instructions
will be promptly sent to you. There will be no charges for repairs of instruments under
warranty, except transportation charges. Estimates of charges for non-warranty or other
service work will always be supplied, if requested, before work begins.
CLAIM FOR DAMAGE IN SIDPMENT
Your instrument should be inspected and tested as soon as it is received. The
instrument is insured for safe delivery. If the instmment is damaged in any way or fails
to operate properly, file a claim with the carrier or, if insured separately, with the
insurance company.
SHIPPING THE INSTRUMENT FOR WARRANTY REPAIR
On receipt of shipping instmctions, forward the instmment prepaid to the
destination indicated. You may use the original shipping carton or any strong container.
Wrap the instrument in heavy paper or a plastic bag and surround it with three or four
inches of shock-absorbing material to cushion it firmly and prevent movement inside the
container.
GENERAL
Your ELCHEMA field office is ready to assist you in any situation, and you are
always welcome to get directly in touch with the ELCHEMA Service Department:
ELCHEMA
Customer Support
P.O. Box 5067
Potsdam, NY 13676
Tel.:
(315) 268-1605
FAX: (315) 268-1709
38
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