VEGA VEGATOR 636 Ex Ship approvals - Manual (Page 18)

18
6 Setup
VEGATOR 636 Ex • Signal conditioning instrument
23446-EN-130627
Switch 1 2 3 4 5 6
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:
•
Two-wire cable on line break and shortcircuit
•
Interruption of the connection cable to the piezo elements
•
Corrosion or damage of the tuning fork (vibrating rod)
•
Break of the tuning fork (vibrating rod)
•
Loss of vibration
•
Too low vibrating frequency
•
Medium penetrating from the vessel side into the sensor
In systems with VEGASWING or VEGAVIB level switches in conjunc-
tion with a two-wire electronics module, a function test can be carried
out. VEGATOR 636 Ex has an integrated test key. The test key is
recessed 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:
•
Switching function of the switching outputs
•
Potential separation of the outputs
•
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 conditions are simulated
during the test:
•
Fault message
•
Empty signal
•
Full signal
Check if all three switching conditions occur in the correct sequence
and the stated duration. If not, there is a fault in the measuring system
(see chapter "Fault rectification").
Note:
Keep in mind that the connected instruments are activated during the
function test. By doing this, you can check the correct function of the
measuring system.
After releasing the key.
The specified times apply with a tolerance of ±20 %.
A-mode B-mode
1 Simulation of a fault signal (approx. 3 s)
Level relay deenergised
Relay control lamp off Relay control lamp off
1 Simulation of a fault signal
Failure lamp
Failure lamp lights Failure lamp lights
Function monitoring
Test key
Test procedure