Options for Field Machine

The Field Machine can be fitted with an extensive range of options that can significantly alter both the appearance and the performance of the instrument. These are listed below followed by a more detailed descriptions for each option.

Field machine with standard options (see specifications)
Extra channels and power
	Sequential Channel's
	2A Power output
	5A Power output
	Up to 100A or more available on request
Quick fit software options
	Galvanodynamic Sweeps
	Harmonic Analysis
	IR Compensation
	Linear Polarisation Resistance Noise
	Bubble Test Software
		BTS option
	Instrument Control DLL
	Customised Software Automated Emailing and Internet Storage of Data
Hardware modifications
	Voltage Input
	Thermocouple Input
	Paint Buffer
	DC Weld Test Option
	AC Weld Test Option (with DC WTO)
	AC Weld Test Option (without DC WTO)
	Offsetting Ability for Weld option
	Electrical Resistance
	GPS (Global Positioning System)
	Critical Pitting Temperature test
	Optional Heater / Stirrer for CPT test
	Limited Distance Modem Base Station
	Limited Distance Modem
	Replacement Electrode Cables
	Direct Instrument to Probe Electrode Cables
	Five Year Warranty

Sequential Channel

Each Field Machine can be fitted with up to 128 sequential channels. Each channel can be treated as if it is independent from the other sequential channels. The Core Running program provided with the instrument will sort out the timing for the tests on each channel. The user must be aware that this is a switched system and that with only one Potentiostat only a single test can be done at any one time.

Additional Software for incorporation in the Sequencer program.

Galvanodynamic Sweeps

This program enables the instrument to be controlled as a Galvanostat rather than a Potentiostat. The program enables both single and multiple cycle Sweeps to be performed as well as long term tests including Linear Polarisation Resistance and Galvanostatic tests.

Harmonic Analysis

A novel and little used technique for measuring the non linear response to a sine wave polarisation. It is unique in that in one simple measurement values for Polarisation Resistance and Tafel slopes bA & bC are obtained. The technique can be used as a long term test in order to monitor corrosion rates with respect to time. The technique typically uses a polarisation of about 0.1Hz or less and measures the 1st 2nd and 3rd Harmonic Current response. The Sequencer program allows the operator to use this technique in series with other perhaps more trusted techniques such as LPR in order to compare results.

IR Compensation

IR Compensation is used to compensate a Potentiodynamic or Potentiostatic test in real time for the depolarising effects of solution resistance. The solution resistance is first measured using an AC signal. The value of this resistance is used together with the polarisation current to adjust the polarisation potential via Ohms Law. To take a simple case where the polarisation resistance and the solution resistance are identical the polarisation potential imposed by the Potentiostat is effectively doubled. Unlike interrupt methods that effectively apply high frequency spikes to the system and have the potential for instability this method maintains control of the cell at all times without any unwanted high frequency polarisations.

Linear Polarisation Resistance Noise (Patent applied for)

A new corrosion monitoring technique that employs the virtues of LPR and Noise. The method is good for multi phase environments such as those experienced in splash zones and multi phase flow. The technique may also be of assistance when used with Rotating Disc Electrode systems. In multiple phase environments such as splash zones or in multiple phase oil / brine solutions the technique gives two results: the average monitored corrosion rate and the corrosivity of the conductive phase. In many cases it is the corrosivity of the conductive phase that is most important. Especially as in the case of an oil/brine mixture the more corrosive brine has a chance of separating out and causing enhanced corrosion rates at a place where a probe does not exist. Note that as far as I am aware no other technique including Electrochemical Noise and Electrical Resistance can do this. Further details on the technique are available under application notes.

Advanced Options for Field Machine

Voltage Input

Voltage inputs can be used to monitor other parameters that have a voltage output such as temperature pressure or velocity. Each voltage input can be selected as a test within the Sequencer program enabling a voltage measurement to be taken at the start or end of any electrochemical test. These inputs can be configured and scaled for display with the correct units together with the long term electrochemical data. Up to four voltage inputs per Gill AC are available on board. Additional voltage inputs are available on request. If requested voltage Inputs can be configured at 0 or 4 to 20mA inputs at no additional charge. A small additional charge is made for direct measurement of a thermocouple.

Paint Buffer

The Paint Buffer is fitted with ultra high impedance components and switches that can handle low currents of the order of 10pA with a good level of resolution below that. It is recommended for use with high impedance cells such as those that are coated or for miniature electrodes. It is housed in a small die-cast box and connects via a cable to the rear panel of appropriately fitted Gill AC’s.

DC Weld Test option (Weld test animation)

This option enables the host instrument to test multiple electrode couples with up to five elements such as encountered with welds or mixed metal systems. Each element in the couple is attached to its own Zero Resistance Ammeter complete with automated current ranges. Thus the individual current response from each element is monitored in both the galvanic and polarisation mode. Versions of the following programs are supplied with this option: Long Term; Cyclic Sweeps and C&V Noise.  These programs are operated through the sequencer program in the normal way. The maximum read rate for C&V Noise is reduced to one reading per second whilst using this option. The specification of the additional ZRAs is as follows:-

- Current Range 10pA to 500mA
- Seven Current Ranges per ZRA.
- Seven Counter Resistors 10 100 1K 10K 100K 1M 10M Ohms
- Input Offset Voltage 10µV

AC Weld Test option

This option enables AC Impedance tests to be applied to the multiple electrode couple. The individual current response to a polarising AC signal is obtained from each of the test electrodes whilst it remains galvanically coupled to the other test electrodes in the cell. It includes the same hardware as with the DC weld test option. 

Offsetting Ability for Weld Test option

This technique enables more than one electrode to be tested in the same cell at the same time. Each test is performed around each electrode's rest potential as if it were isolated from the other electrodes in the couple. A typical use for this technique may be to test 100 painted sample simultaneously during an accelerated exposure test thus reducing the immersion time and also ensuring the test time occurs at the same time for all samples being tested. Letting our minds run free and with quite a bit more complexity the technique enables each of the electrodes in the multiple electrode system to be running completely different tests at the same time whilst still using a single Auxiliary and Reference Electrode. We would like to do a product like this trouble is finding a customer who wants one!

Instrument Control DLL

The Instrument Control DLL is a library of commands that enables operators to control the instrument using their own software. It can be used in Microsoft’s or Borlands C type programming languages. A version that can be controlled from other languages can be supplied at an additional charge.

Electrical Resistance

This option enables the instrument to measure an Electrical Resistance Probe with high resolution. A lot has been made of high accuracy ER measurements in recent times and indeed the electronics is perfectly capable of giving very high resolution measurements and corrosion rates.  However to obtain high accuracy it is important to have very stable temperatures with no variations. In our opinion even temperature fluctuations between the corroding and check elements of a 1/1 000 °C will lead to significant errors when trying to calculate the corrosion rate over a short period of time especially when the corrosion rates are low. Operators can reduce external temperature variations by insulating the probe with waterproof material to reduce the chance of cooling by evaporation. Other than that it comes down to probe design. For higher accuracy try to select a probe that endeavours to reduce any heat difference between the corroding and check elements. ACM can get an indication of the accuracy of the measurement by measuring the resistance of the check element. If this resistance remains constant throughout the test period there is a good likelihood that the corrosion measurements obtained are satisfactory. By measuring the check elements resistance at a set temperature the temperature of the probe whilst in use can be calculated provided the materials thermal coefficient of resistance is known. Our software will include a list of materials with such coefficients.

GPS Tracking System 

This technique enables the location of the corrosion measurement to be recorded with the data for later cross referencing. It does not include the GPS device itself which will interface with the PC. ACM can provide this part with the system if required. The option gives the ability to pre-program the instrument with sequences of electrochemical tests for specific probe locations such that as the operator goes from probe to probe the instrument knows the location of the probe and which tests it is programmed to perform. The data will automatically be added to previous data for that probe.

Bubble Test Software [Software details]

The Bubble Test program is designed for the repetitive testing of corrosion inhibitors. Unlike our standard Sequencer based software which gives great flexibility the Bubble Test program appears to already know what is required of it. Once its initial parameters are set it is ready to perform tests on inhibitors day after day with minimum operator intervention. Tests are typically done in triplicate to gain a level of confidence in the results. Results are presented in a report-ready graphical form that can be printed out at the end of a test including:-

- LPR graph showing LPR; corrosion current or corrosion rate vs time. 
- As above but with markers and labels showing the corrosion rate immediately before the inhibitor was added and the corrosion rate and % inhibition after 1 2 5 10 and 15 hours.
- As above but with operator set titles above and below the graph. 
- Corrosion rate bar graph displaying the corrosion rate on each channel immediately before the inhibitor was added 2 hours after and 16 hours after. Parameters can be changed.
- % inhibition bar graph displaying the % inhibition on each channel at 2 hours and 16 hours after the inhibitor was added. Parameters can be changed.
- Result table displaying the results from the above two bar graphs in a table format with titles and extra information above and below the table. 
- Cyclic Sweep or Tafel type graph showing the results of a Cyclic Sweep done at the end of the Bubble Test. Titles can be added both above and below the Tafel graph.

Such customisation is normal at ACM Instruments hence the depth of options. Just ask for what you want and we will be pleased to supply it.

Replacement Electrode Cables

Replacement cables can be provided to any length required or with any type of termination. It is quite common for operators to specify a complete set of straight through cables for connection directly to a specific probe.