IR measurement/compensation
Smart Manager uses 2 methods to measure IR
value. Measured IR value is recorded on AuxV3|IR data.
Note: If you set parameters for IR measurement,
Smart manager software can NOT read AuxV3 value.
1.
Current Interrupt method
a.
Current interrupt Potentiostatic IR measurement
You can measure IR value using Potentiostatic
IR measurement technique menu on basic techniques.
This will apply potential shortly <3msec and
stop current flowing using FET switch. Smart software measure voltage and
current before and after FET switch on.
Measured data
¨ª Linear fitting
¨ª Exponential fitting
Software read raw data using 2usec sampling
rate and calculate Ru using linear fitting and Exponential fitting
automatically and shows these value at ROI value as the above.
b.
Current interrupt Galvanostatic IR measurement
You can measure IR value using Galvanostatic IR
measurement technique menu on basic techniques.
This will apply current shortly <3msec and
stop current flowing using FET switch. Smart software measure voltage and
current before and after FET switch on.
2.
Positive feedback IR compensation
You can use IR value, which you got current
interrupt IR measurement technique, for positive feedback IR compensation.
You can select ¡°P-feedback¡± for ¡°IR Comp¡± and
input IR value (ohm) on ¡°PF IR (ohm)¡±
You can set IR compensation rate on ¡°information
tab¡±-¡°Advanced¡±. Default value is 85%
If you input 80% compensation and 100Ohm for PF
IR value, SmartManager will compensate 80ohm (100Ohm x80%). SM software read current value and
calculate IR drop using 80ohm (If measured current is 1mA then 80Ohm x 1mA=
80mV will be added to control voltage to compensate IR drop.
3.
Dynamic Method
You can measure IR value during experiment.
Smart Manager Software can support this function using fixed frequency
impedance measurement.
If you do not know frequency value for IR, you
need to run scanning frequency EIS measurement in PEIS or GEIS at high
frequency range and determine frequency value at Zimg is zero value.
.
From the above eis spectra, IR value is 792ohm
and frequency for IR is 3.16 kHz
Dynamic IR measurement will work per each
control step. If control step is constant current, dynamic IR measurement will
do fixed frequency Galvanostatic EIS and if control step is constant potential,
dynamic IR measurement will do fixed frequency Potentiostatic EIS at starting
point.
Parameter setup for dynamic IR measurement is
on ¡°advanced tab¡± in device utility menu
I,
IR vs. time
CC/CV charging CC discharging with dynamic IR
measurement
l IR EIS frequency (Hz): frequency value for
dynamic IR measurement. Unit is Hz.
l IR EIS amplitude (A): amplitude for constant
current control. Unit is A (e.g. for 10mA, input 10m). Bias current is 0A.
l IR EIS amplitude (V): Amplitude for constant
potential control. Unit is V (e.g. for 5mV, input 5m). Bias voltage is Eoc.
l IR CI On time (ms): On rest duration, Current
interrupt On time: Unit is msec *1
l IR CI Sample time(ms): Current interrupt sample
delay time: Unit is msec *1
l IR CI const value(A): On rest duration, Galvanostatic
On current *1
*1: For future function.
b.
Dynamic IR measurement and compensation
Using this function, you do not need to input
PF IR value manually. SmartManager will measure IR value using dynamic IR
measurement and compensate measured IR value.
You can set IR compensation rate on ¡°information
tab¡±-¡°Advanced¡±. Default value is 85%
If smart manager get IR vale as 100 ohm with
dynamic IR measurement and if you input 80% compensation then SmartManager will
compensate 80ohm (100Ohm x80%). SM
software read current value and calculate IR drop using 80ohm (If measured
current is 1mA then 80Ohm x 1mA= 80mV will be added to control voltage to
compensate IR drop)
4.
Compensable Max IR value.
Compensable maximum IR value for IR
compensation is depending on sensing resistor for each current range.
It cannot exceed 1000% of Rs (Sensing resistor)
If input Ru value for positive feedback or
measured IR value by dynamic IR measurement is larger than 10xRs value,
Potentiostat will oscillate.
|
Model |
SP5/MP5 |
SP2/MP2/BP2 |
SP1/MP1/PP1e |
Rs(Sensing resistor value) |
Max Ru value |
|
I range |
5A |
2A |
1A |
100mOhm |
1Ohm |
|
500mA |
200mA |
100mA |
1Ohm |
10Ohm |
|
|
50mA |
20mA |
10mA |
10Ohm |
100Ohm |
|
|
5mA |
2mA |
1mA |
100Ohm |
1kOhm |
|
|
500uA |
200uA |
100uA |
1kOhm |
10kOhm |
|
|
50uA |
20uA |
10uA |
10kOhm |
100kOhm |
|
|
5uA |
2uA |
1uA |
100kOhm |
1MOhm |
|
|
500nA |
200nA |
100nA |
1MOhm |
10Mohm |
|
|
50nA |
20nA |
¡¡ |
10Mohm |
100MOhm |
|
|
5nA |
2nA |
¡¡ |
100MOhm |
1GOhm |
5.
IR measurement only in techniques
You can enable/disable IR measurement for the
following techniques
1.
Basic package (Current Interrupt Method)
A.
Potentiostatic
Ru measurement
B.
Galvanostatic
Ru measurement
2.
Energy
package (Dynamic Method)
A.
CC/CV test
B.
CC/CC test
C.
EVS test
D.
Variable
scan rate CV
E.
Pstat IV
curve
F.
Gstat IV
curve
G.
Steady
state CV
6.
IR measurement and compensation in techniques
You
can enable/disable IR compensation only (positive
feedback) or IR measurement/IR compensation (dynamic) for the following
techniques
1.
Basic
techniques (Positive feedback)
A.
Potentiostatic
B.
Potential
sweep
C.
Cyclic
voltammetry
2.
Corrosion techniques
(positive feedback or dynamic)
A.
Tafel
B.
Potentiodynamic
C.
Cyclic
polarization
D.
polarization
resistance
E.
RpEc trend
F.
Reactivation
potential
3.
Echem
analysis package (positive feedback)
A.
Chronoamperometry
B.
Chronocoulometry
C.
Normal
pulse voltammetry
D.
Differential
pulse voltammetry
E.
Reverse
normal pulse voltammetry
F.
Square
wave voltammetry
G.
Linear
sweep voltammetry
H.
Sampled DC
voltammetry