m_ppxpot  - ZAHNER
External Potentiostats
Installation & Operation
Manual
PP201/211/241
XPOT
07/2013
External Potentiostats
-1-
CAUTION
Prevent the inputs of the device from electrostatic discharge !
This may damage the device.
Do not connect active objects such as batteries or fuel cells to
the power outputs of the device when the device is off !
This may damage the device.
External Potentiostats
-2-
Unpacking
Zahner products are produced carefully, calibrated and tested to achieve a high quality standard. Also
the assembling of the accessories and packing is done with great care. Therefore please check the
shipment directly after receipt whether the device and all accessories are undamaged.
The shipment must contain the following parts:
XPOT
•
•
•
•
•
•
•
XPOT
cable for connection of the EPC40/41/42 (Lemosa - Lemosa)
cable for connection of a PC USB port (USB-A – D-Sub9) with build-in USB-serial converter
3 cables (red, black, blue) BNC – banana
sense cable BNC (green marked) – banana (shielded)
power cord
this manual
PP201/211/241
•
•
•
•
•
•
•
PP201/211/241
cable for connection of the EPC40/41/42 (D-Sub9 - Lemosa)
cable for connection of a PC USB port (USB-A – D-Sub9) with build-in USB-serial converter
2 cables (red and black) with banana plugs (∅ 4mm) and alligator clips
twisted sense cable (Lemosa plug, blue & green cables)
power cord
this manual
-3-
External Potentiostats
Basics
Today, dynamic measurements on electrochemical objects are of great interest. Modern instruments
for impedance measurements, cyclic voltammograms and pulse response experiments provide a
broad frequency range from µHz to MHz. At the same time, they provide a huge impedance range
from µΩ to GΩ. Anyway: for most instruments there is one restriction left, they have a limited current
range in the magnitude of some Amperes maximum. In the field of electrochemical power generation
for example this is only sufficient for 'small' systems.
The electrochemical workstations of the IM6 family provide a current range of ±2,5A (Zennium) and
±3A (IM6) and measure impedances down to some µΩ. Therefore we provide external potentiostats
(EL, PP-Series and XPOT) which can extend the application field of the IM system.
The four quadrant power potentiostats PP201/211/241 provides up to ±40A (PP241) or up to ±20V
(PP211). These devices are designed to do charging/discharging experiments. The XPOT is an
external potentiostat for up to ±500mA and ±10V (±25V compliance voltage) used e.g. for disk/ring
electrode experiments, multi-cell experiments and light source supply for CIMPS.
The external potentiostats are easily integrated in the IM6/Zennium system using EPC40/41/42
controller cards. All functions are controlled directly from the Thales software. Up to 16 external
potentiostats may be controlled by one IM6/Zennium system using up to 4 EPC40/41/42 cards.
With the MultiCell functionality of the IM systems the connected external potentiostats can be used in
parallel. Up to 16 cells may be investigated at the same time.
EPC4 / EPC40 / EPC41 / EPC42
The EPC40/41/42 is able to control up to 4 external potentiostats like the EL101/EL300/EL1000, the
XPOT and the PP201/211/241. Up to four EPC40/41/42 for a total of 16 external devices can be
installed in an IM6 and the Zennium systems.
Each port provides analogue and digital interfaces for the communication of the external device with
the IM system. The analogue part of the port feeds the device with the DC potential and the AC
amplitude at a resolution of 16 bit. Measured current and potential are sent from the external device to
the IM to be treated there in the same way as signals from the internal IM cards. The EPC40/41/42
has a bandwidth of 250 kHz.
A bi-directional serial communication line allows to digitally control the external potentiostat functions
and measuring ranges.
®
The XPOT and PP-Series potentiostats can be controlled by a Windows -PC. In this case they provide
®
the methods Test Sampling as well as U- and I-curves vs. time. They also work as a LabView Virtual
®
Instrument under the LabView software.
Furthermore, you can control the XPOT and PP-Series potentiostats in a mixed mode with an
IM6/Zennium and a PC in parallel. Both devices can be connected and disconnected in operation.
!
Plug or unplug external devices only when both, IM6/Zennium AND the external
device, are switched off. Otherwise the devices may be damaged.
Selecting an external device
All external IM devices are directly controlled by the Thales software. Each device has a unique device
number which is identical with the EPC40/41/42 port number. So, if a device is connected to EPC port
3, you address it with the device number 3. Device number '0' is reserved for the internal potentiostats
of the IM system.
External Potentiostats
-4-
If an RMUX (relay multiplexer) card is installed, the device numbers of the XPOTs start with 17, not
with 1, because the device numbers 1 to 16 are reserved for the 16 RMUX channels then.
To select a device, call the Test Sampling page and click one the # symbol next to the Device Identity
box.
Device
Main
#
An input box will appear where you can input the device number.
Potentiostat
Number: 1
Now the selected device type is shown in the Device Identity box, for example:
Device
EL300#1
•
•
•
#
If no device has been connected to the addressed EPC40/41/42 port an error message is displayed and the software automatically selects the internal potentiostat.
If the selected device is present but has not been activated yet the software starts to calibrate
it automatically.
If an external device is changed the new device has to be calibrated before use. The calibration is carried out only for the selected device. All other calibration data keep unchanged.
If a device number other than 0 is selected, the parameters of the Test Sampling page now are valid
for this device.
The following methods are available for external devices:
EIS
impedance measurement
C/E
parameter impedance measurement
I/E
current potential curve recording
MIE
Multiple parallel current potential curve recording
POL
polarisation measurements
C/V
cyclic voltammetry
AS
series measurements
Specific parameters for these methods are to be edited in the pages related to the method.
Changing devices
When changing the device number, the now inactive device will hold its DC conditions such as DC
potential and on/off status as long as it is selected anew or the system is shut off. On the other hand
only the selected device is internally connected to the FRA. Therefore only this device is able to output
an AC signal superimposed to the DC potential.
External Potentiostats
-5-
PP201 / PP211 / PP241
The PP201/211/241 are external Four-Quadrant-Potentiostats. This means that they are able to sink
and source current up to 20/10/40 A continuously, both positive and negative. Typical applications are
charging/discharging experiments at batteries, accumulators and fuel cells. The PP201/211/241
potentiostats can be operated in both potentiostatic and galvanostatic modes, controlled by the Thales
software. The output as well as the input are electrically isolated up to a maximum difference potential
against ground of ±12V.
Measuring floating objects
On the rear of the PP201/211/241 you will find two connectors with a jumper. If the jumper is set, the
signal ground is connected to ground via a 100 Ω protective resistor. In contrary to the IM potentiostat
(single output stage) the PP (bridge output stage) working electrode is NOT connected to signal
ground. This is necessary, if the test object is floating (no metallic or electrolytic contact to ground). If
any part of the cell is grounded, the jumper must be removed.
silver banana jack (protective ground) ⇔ black banana jack (system ground)
!
When investigating floating objects the jumper must be set.
Stand-alone mode
Besides the usage of the PP201/211/241 as an external potentiostat for an IM6/Zennium system, they
also may be used in a stand-alone mode. The setup is done through an IM system or a PC.
Cell Connections
As its functionality is identical with
the
main
potentiostat,
the
meaning of the cell connections
colours are the same at both
devices. In order to minimize
stray- and mutual inductance the
power lines should be twisted.
Normally the PP201/211/241
should only be connected or
disconnected to the IM system if
both, the IM6/Zennium and the
PP201/211/241 are switched off.
If you want to use the
PP201/211/241 as a stand-alone
device, unselect it in the Test
Sampling page of the Thales
software (you may e.g. change
the device number to the main potentiostat). Now you may unplug the PP201/211/241 at the
EPC40/41/42 connector. For regaining access to the PP201/211/241, connect it to the EPC40/41/42
and select it in the Test Sampling page of the Thales software.
!
Never plug or unplug a PP201/211/241 at the D-Sub9 connector at the backside of the
device with the IM switched on. This may damage the system. It is recommended to
fix the D-Sub9 connector with the screws to prevent accidental unplugging.
External Potentiostats
-6-
If the PP201/211/241 are unplugged while being selected in the Test Sampling page of the Thales
software, it will shut off the current. This is a precaution to prevent undefined situations.
The PP201/211/241 need a warm-up time of about 15 minutes after power on. A calibration procedure
is initiated automatically with the first access by the IM system. If you access a PP201/211/241 during
the warm-up time, please do a forced calibration (EIS menu -> Calibrate) after about 15 minutes.
As the PP201/211/241 are optimised for high current (some 100 mA to 20 A) an erroneous current
display of some µA is acceptable.
Never have a battery connected to the PP when the PP is switched off. This may
damage the PP.
!
1. Full Cell Configuration (Standard Kelvin Scheme)
PP200
PP200
PP200
PP200
PP200
PP200
pot on
power
RE
sense
counter
electrode
test
electrode
power
TE
PP201
PP200
ZAHNER elektrik
This configuration is used if
complete cell is to be investigated.
a
Temp
(H 2 O)
H2
H2
O2
2.a. Half Cell Configuration – Anode
PP200
PP200
PP200
PP200
PP200
PP200
pot on
power
RE
sense
counter
electrode
test
electrode
power
TE
PP201
PP200
ZAHNER elektrik
This configuration is used if the
anodic part of the cell is to be
investigated.
(H 2 O)
H
Ref2
H2
O2
2
External Potentiostats
-7-
2.b. Half Cell Configuration – Cathode
PP200
PP200
PP200
PP200
PP200
PP200
pot on
power
RE
sense
counter
electrode
test
electrode
power
TE
PP201
PP200
ZAHNER elektrik
This configuration is used if the
cathodic part of the cell is to be
investigated.
(H 2 O)
H
Ref1
2
H2
O2
3. Partial Cell Configuration
PP200
PP200
PP200
PP200
PP200
PP200
pot on
power
RE
sense
counter
electrode
test
electrode
power
TE
PP201
PP200
ZAHNER elektrik
This configuration may be used, if a
certain part of a battery or fuel cell
stack has to be investigated.
(H 2 O)
H2
Ref1
Ref2
H2
O2
External Potentiostats
-8-
XPOT
XPOT is a low power 4-quadrant potentiostat which may be used in connection with the impedance
spectrometer IM6/Zennium. Using the XPOT allows parallel investigation of different objects. In such
multi-cell arrangements, potentiostats which are not addressed, will hold their DC-conditions. XPOT
provides a maximum current of ±500mA and a maximum potential of ±10V at a maximum frequency
bandwidth of 100kHz. The compliance voltage is ±25 V.
Connectors & LEDs
Active LED
green = XPOT connected to IM system
orange = potentiostat on
Probe I & E connectors
BNC Cell Connectors
BNC plugs for connecting the cell:
Red = counter electrode
Green = reference electrode
Black = test (working) electrode
Blue = test (working) sense electrode
The shields of the BNC connectors are connected to the test electrode (virtual
ground) via a 2.2kΩ
Ω resistor.
!
The Probe I connector of the XPot is different from the Probe I connector of the
IM6/Zennium. It is used for special XPot extensions such as CIMPS. Do not connect a
UBuffer or a HiZ probe here.
Use of the built-in buffer
The built-in buffer amplifier may be used to increase the dynamic range of the XPOT up to +/-10V. To
select the buffer amplifier mode, call the Check Cell Connections page of the Thales software, select
any connection scheme with buffer and set the corresponding gain factor:
gain factor
output potential range
1
-4V M +4V
0.4
-10 M +10V
Measuring floating objects
Floating and ground referenced objects demand different connections to the potentiostat. Usually, the
ground of the XPOT will be connected to the system ground at its rear panel:
silver banana jack (protective ground) ⇔ black banana jack (system ground)
!
When investigating floating objects the jumper must be set.
-9-
External Potentiostats
Specifications
PP201
PP211
PP241
XPOT
pot/gal
pot/gal
pot/gal
pot/gal
±4V / ±10V
±4V / ±20V
±4V / ±5V
±4V / ±10V
Pot. accuracy
±0.1% / ±1mV
±0.1% / ±1mV
±0.1% / ±1mV
±0.1% / ±1mV
Current range
0A M ±20A
0A M ±10A
0A M ±40A
±10nA - ±500mA
Current accuracy
0.25% / ±1mA
0.25% / ±2mA
0.25% / ±1mA
0.2% / ±100pA
Power dissipation
250W @ Ta
250W @ Ta
250W @ Ta
30W @ Ta
Output power
200W @ Ta
200W @ Ta
200W @ Ta
12W @ Ta
Frequency range
10µHz - 200kHz
10µHz – 200kHz
10µHz – 200kHz
10µHz – 200kHz
Impedance range
1µΩ - 1kΩ
Amb. temperature
0 C M 30 C
IM6/Zennium +
EPC42
or PC
Operating modes
Potential range
*
System
requirements
o
**
o
**
0.1Ω - 1GΩ
0 C M 30 C
0 C M 30 C
0 C M 25 C
IM6/Zennium +
EPC42
or PC
IM6/Zennium +
EPC42
or PC
IM6/Zennium +
EPC42
or PC
1µΩ - 1kΩ
o
*
**
o
1µΩ - 1kΩ
o
o
o
o
Please note that the maximum frequency range only can be achieved with an IM6 or an Zennium equipped with EPC41 or
EPC42. With an IM5d the maximum frequency range of external devices is 30kHz.
**
Impedances below 1mΩ must be measured galvanostatically.
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