Function
15
isoLR275_D00127_00_M_XXEN/07.2018
2.4.2
Self test
A self test can be started automatically or manually by means of the test but-
ton. In order to guarantee high functional reliability, the ISOMETER® provides
comprehensive self test functions. After switching the device to the supply
voltage, all internal measuring functions, the components of the process con-
trol such as data and parameter memory as well as system and earth connec-
tions are checked using the self test functions. The progress of the self test is
shown on the display by a bar graph. Depending on the IT system conditions,
the self test is completed after 15…20 seconds, then the message "Test ok!“
appears on the display for approximately two seconds. Then the device re-
turns to the normal measuring mode and the currently measured value will be
displayed once the measuring time has elapsed.
When a device or connection fault is found, the message "!Error!“ appears on
the display, the device error LED lights, the relay K2 (21-22-24) switches and
the corresponding fault message (see table) will be indicated. If such a device
error occurs, another self test is started after approximately one minute. If no
more faults are detected, the fault message will automatically be deleted, the
system fault LED will go out.
During operation, the self test function can be started by pressing the test
button (internal or external). The self test can also be started automatically
every hour or every 24 hours by selecting the "ISO ADVANCED: Autotest:“ me-
nu.
The alarm relays 1/2 only switch after starting the self test function by pressing
the test button, that means, in case of an automatic self test the relays do not
switch.
