6. TROUBLESHOOTING
The data logger ALMEMO
®
8990-8 can be configured and programmed in
many different ways. It allows for a connection of many different sensors,
additional measuring instruments, alarm signalisers and peripheral devices.
Therefore, it is possible that, under certain conditions, it does not perform as
the user would expect. In most cases this will not be related to a defective
device but to operating errors such as wrong settings or an inadmissible wiring.
The following tests should be performed to correct or to correctly identify the
error.
Error:
Switch-on indicator is not illuminated or no LEDs are permanently on.
Remedy:
Check power supply, recharge battery, switch off and on again,
reinitialise (see 3.5)
Error:
False measured values.
Remedy:
Thoroughly check the programming of the channel (AMR-Control),
query the entire programming by means of the command
P15
(see
manual 6.2.3) and
f1 P15
(see manual 6.10.1)
Error:
Varying meas. values, cyclic measuring point scan blocked.
Remedy:
Check cabling for inadmissible electrical connection,
disconnect all suspicious sensors,
hold hand-held sensors in air or connect dummies and check (short
circuit AB at thermocouples, 100
Ω
at Pt100 sensors), then reconnect
sensors successively and check. If an error occurs with one sensor,
check the wiring, isolate the sensor if necessary, prevent influences
from disturbances by shielding or twisting.
Error:
Data transmission via interface does not function.
Remedy:
Check interface module, connections and settings:
Are both devices set to the same baud rate and transmission mode
(see manual 6.10.12)?
Is the correct COM interface addressed at the computer?
Is the output channel set to "U" (see manual 6.2.2)?
Is the printer set to ONLINE mode?
Are the handshake lines DTR and DSR active?
A small interface tester with LEDs is very useful for checking the data flow
and the handshake lines (during standby mode the data lines TXD and RXD
are on a negative potential of approximately -9V and the diodes are
illuminated green. The handshake lines DSR, DTR, RTS and CTS have a
positive voltage of approxi9V and the LEDs are illuminated red.
During the data transmission the data lines must flash red).
Troubleshooting
ALMEMO
8990-8
17
