User Manual for AML Oceanographic’s MVP
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9
Support
Troubleshooting
Instrument fails to communicate:
Is the connector damaged?
Check the cables
o
Is the data/power cable connected to the instrument and computer?
o
Are there any cuts in the cable?
o
If using a cable other than an AML cable, it should be configured as a null modem
cable.
o
If using multiple cable lengths, the extensions should
not
be configured as null
modem cables.
If using external power over a long cable, check the voltage drop over the cable. Measure
the voltage across a 10 watt, 27Ω, resistor across pins 2 and 3 of the cable. The voltage
must be above 8 volts.
Are the communication settings in the program used on the computer correct?
o
Comm port selection
o
8 bits
o
1 stop bit
o
No parity
o
No hardware flow control
o
Baud rate between 600 and 38,400 baud
Are the communication settings in the instrument correct?
o
Was the instrument specifically set to one baud rate last time? If so, use that baud
rate to resume communications.
o
Was the instrument set to only RS-232 or only RS-485 last time? If so, resume
communications in the required protocol.
o
Was the instrument set to RX OFF last time? If so, a carriage return must be sent
to the instrument immediately after power is applied to interrupt this mode.
o
Was the instrument set to monitor on power up mode? If so, a carriage return
must be sent to the instrument immediately after power is applied to interrupt this
mode. To interrupt monitor on power up, hold down the ENTER key while applying
power to the instrument.
Instrument generates noisy data:
Is the connector damaged, dirty, or corroded?
If connected to external power, is there noise on the power supply? Switch-mode power
supplies are common sources of noise.
Nearby EMI sources such as electric motors, generators, and transformers can create
noise. If possible, move the instrument and its cables away from the noise source.
Are the sensor/s clean?
Are there bubbles on or in the sensor/s?
Are the sensor/s damaged?
