Trouble Alarm Conditions, Causes, And Solutions - Hach 900 MAX Instrument Manual

Trouble Alarm Conditions, Causes, and Solutions

Trouble Condition
Low Main Battery
Memory Battery
Low Slate Memory
Slate Memory Full
Modem Failure
Missed Sample
Purge Failure
Jammed Distributor
Unable to Cool
Unable to Heat
U-Sonic Echo Loss
Xducer Ringing
U-Sonic Failure
RS485 Timed Out
8990apdx_tbl.fm
Cause
Power supply voltage is less than 11 V dc.
Internal memory battery voltage is too low.
Free slate memory is less than 20%. RAM
memory is almost full and will stop
recording soon.
No more slate memory. Unit is in slate memory
mode and cannot log any more data.
Unable to initialize modem PCB.
Sample cycle did not result in getting a sample.
Sensor(s) still detecting liquid after a line purge.
Distributor arm has jammed on an obstruction.
Refrigeration system is unable to reduce
temperature in refrigeration compartment to
user defined setpoint.
Heater is unable to increase temperature in
refrigeration compartment to user defined
setpoint.
The echo has been temporarily deflected by a
change in site conditions such as floating debris
or foam in the channel, wind, etc.
Transducer is operating within the deadband
Transducer not plugged in. Cable damaged.
Transducer thermal sensor damaged.
Communication error between CPU and remote
ultrasonic module.
CPU is not communicating with the
Velocity board.
Not receiving a good velocity reading.
Appendix C
Solution
Change batteries.
Change memory batteries.
Download data from unit, halt and restart the
program or download data, halt, and change
data to wrap mode.
Download data and restart the program or
download data then change the
memory mode.
If the modem is enabled, the problem may be
found on the modem board and the board
may need to be replaced.
—
—
Remove obstruction
—
—
Check for excessive foam. Remove any debris
or build-up.
—
Check that the transducer is plugged in and
that there is no damage to the sensor.
—
Wait a few minutes to see if it goes away, if it
continues it is an indication that there is a
problem with the CPU board.
If the logging interval is 1 or 2 minutes and
conditions are poor with the problem
continuing indefinitely, try increasing the
logging interval to allow more time to capture
the signal.
Troubleshooting and Error Messages
Page 129