FM256 Technical Support - Page 2

How do I download data if I do not have the latest Geoplot?
If you have a copy of Geoplot earlier than version '3.00h1' then there will be no specific provision in the Input Template for an FM256. (You can check version by selecting 'About Geoplot' on the Help menu). You can still download data by fooling Geoplot into thinking that it is dealing with an FM36 instrument; you will also require an FM18/36 data dump lead - this method will not work with an FM256 data dump lead. Set Input Template details as though it were an FM36 (Baud Rate normally = 2400) and on the FM256 set Baud Rate = '2400' and Data Format = 'Fast ASCII'. Proceed as though you were downloading from an FM36; the data will be recorded as though it were FM36 data, observable when you view File Details in Geoplot.
A higher download speed can be achieved as follows, but
only if you are not using Log Zero Drift. Set Input Template details as though it were an RM15 (Baud Rate normally = 9600) and on the FM256 set Baud Rate = '9600' and Data Format = 'Fast ASCII'. Proceed as though you were downloading from an RM15; the data will be recorded as though it were RM15 data, observable when you view File Details in Geoplot. You will need to change units from ohms to nT for each grid by using Units on the Edit menu. Survey Type will still be recorded as Resistance in File Details so for archiving purposes you should use Windows Notepad or any other text editor to modify the .grd file accordingly.
If you have an early copy of Geoplot 3 then please ask for the latest version, stating serial number and if you have dongle or software protection - this code can usually be emailed to you free of charge. If you have DOS based Geoplot 2 then you will need to purchase an upgrade to Geoplot 3 to obtain full FM256 system support.

How do I download data if I only have an FM18/36 download cable?
Should you only have an older FM18/36 data dump cable available then this may be used in an emergency - however it should only be used for smaller data dumps and / or slower baud rates since handshaking is not implemented in this cable.

What do I do if I am having difficulty downloading the data?
Initial Checks
If you experience problems downloading data then initial checks should include the following initial checks:

•  Ensure you are using the correct download cable - see Appendix C in the manual for details.
•  Ensure the download cable is plugged into both the FM256 and the computer.
•  Inspect the cable for damage - if possible test continuity of the cable according to details in Appd. C.
•  Check that the serial port on the computer is enabled - you may need to inspect the BIOS settings to confirm this.
Please note that making incorrect changes to the system bios may prevent your PC from booting so consult your system documentation very carefully before doing so.
•  Try downloading to another to eliminate the computer serial port as a problem.

Computer Setup
Before you download you ensure that screen savers, battery standby, battery monitor, hard disk standby are disabled - a reminder is given on the dialog boxes. If you do not disable them, then when these become active they can interrupt the real-time handling of the data flow into the PC, leading to loss of data. As well as disabling screen savers, battery standby and battery monitor, make sure there are no other background tasks operating that may interrogate the serial ports or acquire CPU time, for example:

•  Some personal organiser synchronising software, by default, continually scans the serial ports for activity--this must be disabled before downloading data.
•  Some virus checkers may need disabling if they monitor the serial port and interupt the flow of data.
•  Software for modems may take control of the serial port and must be disabled. In some circumstance the serial port may not be active, most common on computers with internal modems and must be activated before you can download data. This may be done either using special utilities provided with your computer or by changing the system bios settings when you first start your computer.
Please note that making incorrect changes to the system bios may prevent your PC from booting so consult your system documentation very carefully before doing so.
•  It is possible that if Windows, or one of its components, is not correctly installed, or conflicts occur within the hardware installation then you may have difficulty downloading data correctly. For example, you may have a mechanical switch that connects a single serial port to either a modem or an instrument for download - however, the modem driver / installation may be permanently trying to access the serial port at the same time.
•  You should disable Infrared ports since they also use the serial port and may interrogate it every 3 seconds by default.
•  Do not use a serial mouse since this will generate interupts that may affect data handling.
•  Running a portable computer from battery, rather than the mains supply can solve download difficulties (this was experienced on a DELL computer running Windows 98).

In all the above cases you should always restart your download software after making setup changes, and in many cases you will also have to reboot the operating system.

Geoplot Setup
If you are using Geoplot 3 to download data then check the following points:

•  Make sure the "Download RS232 COMM port" setting in the Environment Options, Input tab is set to the correct port number--by default this "1". Ensure that there is not a break in the cable.
•  Data download requires the version of MSCOMM.VBX dated 5/12/93. This is automatically installed with the other DLL and VBX files. If you experience problems with data download check to see if there are any other versions present on your machine and ensure it is not dated earlier than 5/12/93.
•  A progress report consisting of a bar and reading count is shown as the data is downloaded. If there is a large quantity of data and the computer is slow then you may get a "Buffer Overflow" or "Port Overrun" error message. If so, then go to Environment options and change the progress report to either Bar only or none at all.  Also, do not move the mouse or progress form during download since this will generate a Windows call that will be serviced in preference to handling the RS232 data. The internal buffer may not have sufficient capacity to temporarily store the incoming data in the interim.
•  If you are using Windows 3.1 on an older, slower, computer (e.g. 486DX2) then it is advisable to make some changes to your System.ini file to improve throughput of data into the RS232 port and avoid buffer overflow. In the [386Enh] section add :
COMxBuffer=8192     (where x = the Comm port number)
If you are using Windows 3.11 you may also need to add :

The Computer does not have a Serial Port
If your PC does not possess a serial RS232 port but does have a USB port then you should use a USB to serial adapter to download data. This could also be a solution if you continue to experience difficulties using a conventional serial port - see above. You will need Windows 95 with USB support, Windows 98 or higher. The driver software that accompanies the converter will probably assign its virtual COMM port to be other than "1". Typically this is "4" and, if using Geoplot 3, you should set the Input tab in Environment Options accordingly. If you use a USB converter you will find that you have to exit Geoplot after a download in order to clear data left in the PC's buffer. For example, if you come to dump data and see the message "Receiving data…" instead of the normal "Waiting for data…", even though you have not yet pressed DUMP on the instrument, this is a sure sign that data is still left in the PC's buffer. If you do not exit Geoplot at this stage and continue downloading, the data will be scrambled.

Why is the data is scrambled?
If the data appears to be scrambled check the following as these can cause such a problem if not followed:

•  When downloading data the settings for Log Zero Drift must match on the instrument and software.
•  When downloading data the settings for Data Format
must match on the instrument and software.
•  You must exit from the download software after dumping via a USB to Serial converter in order to clear the computers buffer prior to the next download - see above.

Try downloading the data again if one of the above points was the cause of the problem. Even if the memory has been cleared, the old data still exists in memory and can be dumped again, providing no more data has been logged in the meantime which will have overwritten previous data.

What do I do if there is water in the FM256?
If you have been working in extremely heavy or driving rain and water has entered the electronics housing of the instrument then you should not use the instrument until it has dried out thoroughly. Remove the lid and leave the instrument in a warm dry environment for at least 24 hours, preferably longer. Take great care not to damage internal wiring if you remove the lid. DO NOT OPERATE WITH MOISTURE INSIDE. If you attempt to operate the instrument with moisture inside electrolytic action could severely damage the electronics. If water is present in sufficient quantities that you need to tip it out, an environmental seal may have been damaged and the instrument ideally requires servicing. Once dried out you could continue to use the instrument temporarily, providing weather conditions have improved, and then have a servicing performed after the survey.

Why does the NiMH battery pack not hold its charge?
The NiMH battery pack can be recharged up to approximately 600 times. After this number of recharges it will start to lose its ability to retain charge and will need replacing.

What can I do in an emergency if I cannot obtain the correct size memory backup battery?
A common battery is the CR2025, DL2025 or ECR2025 3V Lithium battery. It is smaller in diameter and thinner than the normal CR2450, DL2450 or ECR2450 battery. You can use this in an emergency if you cannot obtain the normal sized battery. To make up the thickness use this battery, together with a coin (such as a 10p pice) used as a spacer - ensure the coin is not too magnetic. Bear in mind that the contact method is not ideal and a normal sized battery should be fitted as soon as possible. It is vital that you insert the battery the correct way up - the retaining clip is marked with a '+' sign and must connect to the positive side of the battery - if you connect it the wrong way round the circuitry inside will be damaged.

What do I do if a Start-Stop button stops working?
The button of a Start-Stop switch can become stuck down sometimes when working in very wet weather. Water enters the very small gap between the button and the switch surround and capilliary forces hold the button down. Try blowing the water out and, at the same time, use your finger to gently move the button from side to side to release the water and button. If this does not work, taking the instrument into a dry atmosphere will allow the water to evaporate and then the button can be released by gently moving with a finger. The Log key on the front panel or an external hand-log key can be used as alternatives to starting the internal sample trigger system when the Start-Stop switch is out of action. Should a Start-Stop switch need replacing, a spare can be ordered for the user to fit - there is no soldering involved and an internal plug push fits into a connector on the back of the new switch.

Back to top of page