3 operation – KROHNE OPTISWITCH 3100C NAMUR EN User Manual

Page 8

It functions even when exposed to strong external vibration or

changing products.
Solid detection in water

If OPTISWITCH 3100 C was ordered for detection of solids in

water, the tuning fork is adjusted to the density of water. In the

air or when covered by water (density: 1 g/cm³/0.036 lbs/in)

OPTISWITCH 3100 C signals "uncovered". Only if the

vibrating element is also covered with solids (e.g. sand,

sludge, gravel etc.) will the sensor signal "covered".
Fault monitoring

The electronics of OPTISWITCH 3100 C continuously mon-

itors the following criteria:

Correct vibrating frequency

Line break to the piezo drive

If one of these faults is detected, the electronics signals this via

a deﬁned current to the signal conditioning instrument. The

connection cable to the vibrating element is also monitored.

The tuning fork is piezoelectrically energised and vibrates at its

mechanical resonance frequency of approx. 150 Hz. When the

tuning fork is submerged in the product, the vibration

amplitude changes. This change is detected by the integrated

oscillator and converted into a switching command.

OPTISWITCH 3100 C with NAMUR electronics can be

connected to diﬀerent NAMUR ampliﬁers depending on your

requirements. The speciﬁcations for NAMUR ampliﬁers are

available in the "Technical data".
The exact range of the power supply is stated in the "Technical

data" in the "Supplement".

3.3 Operation

With the factory setting, products with a density of >0.02 g/cm³

(>0.0008 lbs/in³) can be measured. The instrument can also

be adapted to products with lower density >0.008 g/cm³

(>0.0003 lbs/in³).
On the electronics module you will ﬁnd the following indicating

and adjustment elements:

signal lamp for indication of the switching condition (yellow)

potentiometer for adaptation to the product density

Mode switch to select the switching condition (reverse

characteristics)

Physical principle

Power supply

OPTISWITCH 3100 C - with NAMUR output

Product description

31356

-EN
-060830