50-613 Kotron
®
Series 82 CE RF Level Transmitter
16
4. Span point cannot be increased to 20 mA at high level.
a. Span controls incorrectly set
— Turn span controls clockwise
b. Insufficient probe capacitance
— Increase span length or probe;
— Increase probe diameter;
— Locate probe closer to wall(s);
— Use probe with higher dielectric insulation;
— Install stilling well;
— Use smaller diameter stilling well;
— Consult factory.
c. Excessive loop resistance
— Refer to chart on page 18 for maximum allowable
loop resistance.
5. Span current cannot be reduced to 20 mA at high level.
a. Span controls set too high
— Turn span controls counterclockwise
b. Excessive probe capacitance
— Maximum span range is:
110 pF – switches open
485 pF – switch 1 closed
1950 pF – switch 2 closed
4000 pF – switch 3 closed
— Decrease span length of probe;
— Remove stilling well;
— Increase diameter of stilling;
— Locate probe farther from walls;
— Use probe with lower dielectric insulation; or
— Replace bare probe with an insulated one;
— Consult factory.
c. Low probe resistance to ground
— Probe resistance must be more than 10 megohms.
— Consult factory.
2.3.3 Operation
1. Loop current oscillates or hunts.
a. Waves or disturbances in medium
— Use stilling well;
— Use external cage or standpipe for
transmitter;
— Correct instability of medium.
b. Probe moving within vessel
— Improve probe anchoring
