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Frequently Asked Questions

Level Controller Topic: Possible to Use with 15 kΩ or less, but may Cause Reset Failure

 

FAQ No. FAQ01480

 

Question

 

Why do the specifications for the 61F High-sensitivity Floatless Level Controller say, 'possible to use with 15 kΩ or less, however, this may cause reset failure'?

 


Answer

The interelectrode voltage of 61F is AC. This generates a floating capacitance between ground and the cable that connects the electrode bar to 61F body. The current that flows due to this cable-to-ground floating capacitance causes the reset failure.


The reset current for 61F High-sensitivity Controller is 0.05 mA AC min. If the current flowing through the ground capacity is, for example, 0.1 mA, there will be a reset failure because of the reset current (0.05 mA AC min.) even when there is no liquid between the electrodes.
 

Countermeasures:


1. Shorten the cable between the Electrode and 61F Controller. (For the 61F-GP-N8 High-sensitivity Controller, use a 0.75-mm2, 3-conductor, cabtyre cable that is 50 m or less in length.)

2. Use a General-purpose Controller for applications where the liquid resistance can be detected at ordinary sensitivity (0 to 4 kΩ).

 

 
Other Level Controller FAQs

 How do you measure the resistance between electrodes?

 What does operation resistance mean?