Trouble-Shooting - Ahlborn ALMEMO 2490-2 Operating Instructions Manual

13. Trouble-shooting

13. TROUBLE-SHOOTING
The ALMEMO ®
grammed in many versatile ways. It is suitable for connecting a wide variety of
different sensors, additional measuring instruments, alarm signaling devices,
and peripheral equipment. Given these numerous possibilities the device may
in certain circumstances not behave quite as expected. The cause of such un-
expected behavior is only very rarely a device defect; more usually it is incor-
rect operation by the user, an invalid setting, or unsuitable cabling. In such
event try to pinpoint and clear the problem with the aid of the following tests.
Error: No display, display malfunction, keys do not react
Remedy: Check the power supply; replace the batteries; switch off and then
on again; if necessary re-initialize (see 7.5).
Error: Measured values are incorrect.
Remedy: Switch Device OFF / ON, press key and hold
channel programming very carefully, especially the base value and
zero-point.
Error: Fluctuating measured values or the system hangs in mid-operation.
Remedy: Check the cabling for any inadmissible electrical connections,
Unplug any suspicious sensors.
Connect hand-held sensors in air or phantoms (for thermocouples
short-circuit AB, for PT100 sensors use 100Ω) and check.
Connect the sensors again one at a time and check successively.
If a fault persists for any one connection, then check all wiring; if ne-
cessary, insulate the sensor and eliminate interference by using
shielded or twisted wiring.
Error: ´CALEr´ is displayed when the device is switched on.
Remedy: The calibration of a measuring range may have become misadjus-
ted. The device must be recalibrated at the factory.
Error: Data transmission via the interface does not function.
Remedy: Check interface module, connections, and settings.
Are both devices set to the same baud rate and transmission
mode ?
Is the correct COM interface on the computer being addressed ?
To check the data flow and the handshake lines a small interface
tester with LEDs comes in very handy; (in ready-to-operate status
the data lines TXD, RXD carry negative potential of approx. -9V and
the LEDs light up green, whereas the handshake lines DSR, DTR,
RTS, CTS carry approx. +9V positive voltage and the LEDs light up
red. For the duration of data transmission the data LEDs should
flash red. Check data transmission by means of a terminal (AMR-
Control, WIN-Control, WINDOWS-Terminal).
Address the device using its assigned device number´Gxy´ (see
Manual 6.2.1).
30 ALMEMO
2490 measuring instrument can be configured and pro-
2490
®
CLR . Check all the