Bender ISOMETER IRDH575, Manual

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Function
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IRDH575_D00089_05_M_XXEN/01.2020
This has the advantage that no auxiliary contacts of a coupling switch are re-
quired. Furthermore, this solution is recommended for IT systems coupled via
capacitances or diodes.
3.5.7 Self test
In order to guarantee high functional reliability, the ISOMETER® provides com-
prehensive self test functions. After switching the supply voltage on, all inter-
nal measuring functions, the components of the process control such as data
and parameter memory as well as system and earth connections are checked
using the self test functions. The progress of the self test is indicated on the
display by a bar graph. Depending on the system conditions, the duration of
the self test is 15… 20 seconds, then the device indicates "Test ok" for appro-
ximately 2 seconds. Then the device returns to normal measuring mode and
the current measuring value is displayed after the expiry of the reading time.
When a fault is found the message "!Error!" appears on the display, the device
fault relay K3 (31-32-34) drops, the device fault LED lights up and the respec-
tive error message (see table) is indicated. If such a device fault occurs, a self
test will be started every 60 seconds. If no more malfunction is detected, the
fault message will automatically be deleted, the device fault LED extinguishes
and the device fault relay K3 energizes again.
During operation, the self test function can be started by pressing the TEST
button (internal or external) or automatically every hour or every 24 hours by
selecting "ISO ADVANCED": Autotest:" in the menu. The alarm relays ALARM 1/
2 can only switch after starting the self test function by pressing the TEST but-
ton, that means if an automatic self test has been selected, the alarm relays do
not switch.
If the on/off switching of the supply voltage is not possible for
technical reasons, a RESET of the device can be carried out by
pressing the "INFO", "RESET" and "MENU" key simultaneously.