Task Masters based on Potentiostat There are a number of options to specify when designing a multiple channel potentiostat based Task Master.

A: Number of channels required.
B: Multiplexed Potentiostat system.
C: Multiple Potentiostat system.
D: Current Range of each Potentiostat
E: Electrical Isolation of each Potentiostat
F: Test Type
G: Read Rate

A: Number of Channels Required.

Each channel can monitor a single cell typically containing 2 or 3 electrodes. Thus in order to polarise 12 test electrodes a 12 channel system is required.

B: Multiplexed Potentiostat system.

A multiplexed system consists of a single Potentiostat that is switched between channels. Thus only one channel can be controlled at the same time. The technique is cost effective especially if a complex Potentiostat is required. The same technique is employed with instruments such as the Gill 8 & Gill 12. Channels that are not connected to the Potentiostat however are isolated. Thus such a system is not suitable for tests that need to be potentiostatically controlled for a period of time as only one channel is controlled at once. 

C: Multiple Potentiostat System

Such a system comprises of a Potentiostat per channel. This enables the Potential control of all channels at all times

D: Current Range of each Potentiostat

A typical single range Potentiostat will give a comfortable current range over four decades. Current ranges up to 7mA are the most cost effective. Each Potentiostat can have a wider range of current using switched current ranges. This could be relatively simple in that each Potentiostat has only two current ranges or a wide spread giving a current range from 10pA to 5Amps. You would need to specify the current range required.

E: Electrical Isolation of each Potentiostat

Electrical isolation enables each potentiostat and thus its associated electrodes to be electrically isolated from the other channels. With electrical isolation electrodes from all potentiostats can be placed in the same cell at the same time without any externally imposed polarisation between channels. Multiple channel switched potentiostat systems also offer isolation between channels.

F: Test Type

Any potentiostatic or potentiodynamic test type can be specified with a Task Master including potentiostatic; harmonic analysis; potential pulse; AC impedance or cyclic voltammetry.

G: Read Rate:

The read rate depends on the design of the system and the time constraints of the type of test itself. One reading per minute for each channel is typical for types of tests that are quick to monitor such as potentiostatic tests. In a typical cost effective instrument the measurement technology is switched between potentiostats. However this need not be the case.  Task masters can be supplied that perform and monitor more complicated tests on all channels at the same time. 

Examples of Potentiostat based Task Masters we have designed.

AC 40     A forty channel sequential system using AC Impedance on coated samples. This system monitored both capacitance and impedance at specific frequencies as well as performing a full AC Impedance scan from high to low frequencies

Pot 16     A 16 channel multiple potentiostat system for cathodic disbondment tests on painted samples. [Specifications]

LPR 4     A four channel LPR system with distributed and remote potentiostat units. Each potentiostat had four current ranges. It was designed to monitor atmospheric corrosion close to the reactor at a de-commissioned nuclear power station over a period of years.

Due to the great variety of these customised instruments we have not supplied pricing information. Please decide what you want using the above information as a guide and ask ACM Instruments for a quotation. Alternatively contact us by 'phone and we can ask the necessary questions and quote to your specifications.