Operation – KROHNE OPTIFLEX 1300C EN User Manual

Page 97

OPERATION

OPTIFLEX 1300 C

www.krohne.com

03/2014 - 4000172306 - HB OPTIFLEX 1300 R07 en

6.4.10 How to measure products with a low dielectric constant (ε

)

The device can measure the level of liquids and solids with low dielectric constants. The
minimum value depends on the probe type and the measuring mode.

Measuring mode limits

In direct mode, the device directly receives the reflection of the signal from the surface of the
tank contents.

TBF mode lets the device measure one product with low ε

. Unlike direct mode, the signal travels

through the liquid or solid to the end of the probe. It is reflected back to the electronics. The
liquid or solid must have a stable dielectric constant for accurate measurement.

How to prepare an installation for a device that measures in TBF mode

• If the probe end is not attached, the minimum distance between the probe end (of single cable

or rod probes) and the tank bottom must be 300 mm / 12¨. If the device has a coaxial, double
rod or cable probe, it is not necessary to have a minimum distance between the probe end and
the tank bottom.

• There must be no objects in a diameter of 600 mm / 24¨ around a single probe. There must be

no objects in a diameter of 200 mm / 8¨ around a double probe. It is not necessary to have an
empty space around a coaxial probe.

How to configure the device to measure in TBF mode

• Go to Supervisor > Advanced Setup > Installation Setup > Measuring Mode

Supervisor > Advanced Setup > Installation Setup > Measuring Mode

Supervisor > Advanced Setup > Installation Setup > Measuring Mode.

• Select TBF from the menu. Push [^

^].

• To enter the exact value of the product's dielectric constant, go to Supervisor > Advanced

Supervisor > Advanced

Setup > Installation Setup > Product Er

Setup > Installation Setup > Product Er.

• Type in the exact value. Push [^

^].

Measuring mode

Probe type

Minimum dielectric constant

Direct

Coaxial

1.4

All other probes

1.6

TBF

All probes

1.1

CAUTION!
Do not change the product ε

value in Product ε

(menu item C.1.14) unless the new value is

known. If an incorrect value is used, the device will not measure accurately.

INFORMATION!
The device usually measures in Automatic

Automatic

Automatic mode. If it cannot find a signal in Direct

Direct

Direct mode, the

device will switch automatically to TBF

TBF

TBF mode.