50-604 Kotron Model 804 Sentinel II RF Level Transmitter
20
3.0
Reference Information
3.1
Troubleshooting
Caution:
In hazardous areas, do not remove housing until power is
disconnected and atmosphere is determined to be
safe.The Sentinel II contains a comprehensive diagnostics
system that can assist in locating the cause of a specific
fault. This system also allows the user to test the 4–20 mA
and discrete (relay) outputs to ensure satisfactory opera-
tion of the system. The following section defines each
function of the diagnostics system:
3.1.1 Test Relays
The Test Relays menu provides a controlled contact
closure for each relay to test its integrity. A password is
required.
3.1.2 Test 4–20 Output
The 4–20 Loop Output menu provides a means for testing
the 4–20 mA output. Once the desired loop current is
entered, the Model 804 will drive the output loop to this
current value.
3.1.3 Signal Values
The Signal Values menu provides a means of examining
the signals between the probe and the CCO (Capacitance
Controlled Oscillator). The three signals are:
3.1.3.1 CCO int. cap.
This signal represents the time period of the oscillator
using the internal test capacitor. This fixed capacitor is
switched into the circuit to test the oscillator. A value of
approximately 475 and 525 µsec. is acceptable.
3.1.3.2 Open probe
This signal represents the time period of the oscillator with
no capacitor attached (the probe and the fixed capacitor
are switched out of the circuit). A value between 150 µsec.
and 250 µsec. is acceptable.
3.1.3.3 CCO probe
This signal represents the time period of the oscillator
using the probe’s capacitance The minimum should be
equal to or greater than the open probe value; the maxi-
mum should not exceed 70,000 µsec.
