Adding A Padding Capacitor - Ametek Drexelbrook Z-tron Level Control 502-302X Series Installation And Operating Instructions Manual

502-302 Series Z-tron
X
4.7 Adding a
Padding Capacitor
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TM Level Control
The tuning range of the 402-302X transmitter is 0-8 pico-
farads. Long insertion length sensing elements or sensing
elements mounted in pipes or near metal objects may
generate in excess of 8 pF resulting in the inability to find
a tune point (the unit will always show alarm). Figure 4-6
shows the wiring for adding a padding capacitor.
The addition of an external padding capacitor will increase
the tuning range of the unit. For example, adding a 10 pF
capacitor will result in a 10-18 pF tuning range.
When a padding capacitor is required, a 10 pF NPO ca-
pacitor should be added to the terminals as shown in
Figure 4-6. If the unit is still out of tuning range, add an-
other 10 pF in parallel. If still unable to calibrate, contact
the Factory Service department at 1-800-527-6297.
Padding Capacitor
19
Calibration
Figure 4-6