KROHNE SU 501 EX EN - Manual (Page 18)

Switch 1 2 3 4 5 6
Time za ze 2 s 6 s 12 s
0.2 s A/B off off off off off
0.5 s A/B
1)
off off off
2 s A/B on off off
6 s A/B off on off
8 s A/B on on off
12 s A/B off off on
14 s A/B on off on
18 s A/B off on on
20 s A/B on on on
The measuring system is continuously monitored. The
following criteria are checked:
l
Two-wire cable on line break and shortcircuit
l
Interruption of the connection cable to the piezo elements
l Corrosion or damage of the tuning fork (vibrating rod)
l
Break of the tuning fork (vibrating rod)
l
no vibration
l
Too low vibrating frequency
l
Medium penetrating from the vessel side into the sensor
In systems with OPTISWITCH level switches in conjunction
with a two-wire oscillator, a function test can be carried out. SU
501 Ex has an integrated test key. The test key is lowered in
the front plate of the signal conditioning instrument. Push the
test key with a suitable object (e.g. screwdriver, pen etc.).
By pushing the key, the system is checked on the following
criteria:
l
Switching function of the switching outputs
l Potential separation of the outputs
l
The signal processing of the signal conditioning instrument
After pushing the test key, the complete measuring system is
checked on correct function. The following operating condi-
tions are simulated during the test:
l
Fault signal
l
Empty signal
1) Set alternately switch 2 and/or 3 to "on". The times apply to the adjusted
delay mode.
Fault monitoring
Test key
18 SU 501 Ex - Signal conditioning instrument
Set up
27953
-EN
-050616