Trouble-Shooting - Ahlborn ALMEMO 2590-2A Operating Instructions Manual

TROUBLE-SHOOTING

16.
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 incorrect
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: Check all the channel programming very carefully, especially the base
value and zero-point (sensor programming and special functions
menu).
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 100) and check.
Then connect the sensors again one at a time and check succes-
sively; if a fault persists for any one connection check the wiring; if
necessary, insulate the sensor and eliminate interference by using
shielded or twisted wiring.
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 ?
(see 14.5)
Is the correct COM interface on the computer being addressed ?
To check the data flow 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 positive
voltage of approx. +9V and the LEDs light up red. For the duration of
data
Check data transmission by means of a terminal (ALMEMO
WIN-Control, WINDOWS-Terminal).
Address the device using its assigned device number´Gxy´ (see Man-
ual 6.2.1).
Enter <ctrl Q> for XON, if the device is in the XOFF status.
Check the programming by means of ´P15´ (see Manual 6.2.3).
Test the transmit line by entering a cycle using command ´Z123456´
and check in the display.
Test the receive line by pressing
72
2590A measuring instrument can be configured and pro-
transmission the data LEDs
<MANU>
should flash
and check in the display.
red.
-Control,
®