Hydrological Services Pty Ltd
Data Logger Model ML1-420
©
Copyright
ML1-420 100-30
Issue 1.00 6 Apr, 2011
6. Fault
Finding
This fault finding guide should be used by the ML1-420 user before they consult the manufacturer to
assist with specific problems.
LED does not flash once a second.
If you have attempted to load new software / firmware, then attempt the procedure again.
The internal battery may be flat. Remove the 4 screws on the top of the MiniLog and remove
the top cover exposing the PCB and battery. Use a DVM to measure the battery voltage. An
alkaline battery should be about 1.5V and a lithium battery should be between 3.2V and 3.6V
If the voltage looks low, then replace the battery.
If LED still does not flash after the above has been checked, return the logger to the supplier
for service.
No communications from logger.
Check if LED flashes when sending a character to the logger. If not, see if the LED flashes in
response to an external event. The RS232 handshake lines provide power to the MiniLog – so
make sure the RTS and DTR signal are in their hi state – especially if you are using a third
party terminal emulation package.
Check the logger baud rate, number of bits and parity (8/N/1) matches that of the terminal
emulation program being used on the computer. If you receive strange characters in response
to a carriage return, then the baud rates probably don’t match - change the baud rate on the
terminal emulation program, and try again.
Try all 7 baud rates from 1200 to 57600 on the PC.
Check the Tx, Rx, RTS, DTR and Gnd wiring to the logger from the computer.
Check that the terminal emulation program is working, by disconnecting the logger and
shorting the Tx and Rx wires together, and type on the computer. You should get each
character twice on the screen. Try the other available comm ports on the PC.
What I type on the computer the characters do not appear, but the logger seems to respond OK.
Set the third party terminal emulation program “Local echo” to on.
An external event flashes the LED but nothing gets transmitted.
Set the event flag (EV) to on to allow events to be transmitted. However the flag should be off
if the logger is connected to an intelligent modem.
Check that the multiplier (
mm
) in the increment parameter (INC=x.x/
mm
) is set to a
reasonable number. Remember that
mm
contact closures represent one event.
When I type <CR> (Enter ) on the computer the LED flashes but I get no reply.
Set the response flag (RE) to on. This flag is used to stop the logger responding to data from
an intelligent modem. If you are talking through a modem then this is correct, you will not get
a response to a <CR> (Enter ) because the response flag must be left off.
The logger will not accept my password.
Check that you have the correct password, and you are entering it in the correct upper and
lower case. The factory default password is “BOMM”
If still no success, the logger must be returned to the manufacturer, to set a default password.
Keep your password written down in a secure place.