OHW

OHW

OHW

OHWG

G

G

G Series

Series

Series

Series

Wiegand

Wiegand

Wiegand

Wiegand sensor

sensor

sensor

sensor

Page 4

Nanjing

Nanjing

Nanjing

Nanjing Ouzhuo

Ouzhuo

Ouzhuo

Ouzhuo Technology

Technology

Technology

Technology co.,

co.,

co.,

co., Ltd

Ltd

Ltd

Ltd

www.ohhall.com

www.zbling.com

Tel：86-25-52312738，86-25-83247886

FAX: 86-25-52312738

E-mail: ohhall@163.com

Magnetic

Magnetic

Magnetic

Magnetic Circuit

Circuit

Circuit

Circuit Design

Design

Design

Design

The right and reasonable magnetic circuit design is very important for the operation of

wiegand sensor.

1) Dual magnetic poles ( N, S ) should trigger Alternately. The distance between poles

should be close to or larger than the length of the sensor. For example, ferrite toroidal

magnetic ring ( φ9.5 mm ) can be used in water meter, it also can apply a pair of alnico.

The distance between the two poles should be not less than 9mm.

2) When installing magnet, make sure the direction of the magnetic line parallel to the

sensor wire( refer to the triggering mode and the installlation method )

3) The triggering magnetic flux density in the position of the Sensitive wire should between

the min and max value in the characteristic list. In some application, such as calorimeter,

the magnetic intensity should be the best value. Since the magnetic intensity will reduce

with the increase of ambient temperature and the longer distance between the magnet

and sensor.

4) Magnetic shielding is necessary to prevent ambient stray magnetic field interference.

But the distance between shielding cover and magnetic ring or sensitive wire should be

not less than 10mm, and no other magnetic materials, such as iron screw.

Electric

Electric

Electric

Electric Circuit

Circuit

Circuit

Circuit Designing

Designing

Designing

Designing

In order to avoid some possible intreference and assure the accuracy of counting, some

suggestions is offered as follows:

1)The output signal of Wiegand sensor should be shaped by wave shaping circuit first,

and then input into

the two tnterfaces Io1 and Io2 of single-chip microcomputer.

After

signal haping and amplification, there is a low output voltage similar to a rectangle on the

output side Vo1 (note: it is not a negative pulse), and a high output voltage similar to a

rectangle on the output side Vo2.

Amplitude of the square wave is equal to supply

voltage, and the width is 20 to 30μS.

2 When designing the software, make sure that counter plus "1" after collecting both low

and high output voltage.

That is meaning, the signal-chip microcomputer I 01 only need

to collect the first low output voltage and ignore others. The same as the signal-chip

microcomputer I 02 which only collect high output voltage.

3)The software can be used to recognize the output signals and interference signals, The

Pulse Width of output signals are usually fixed, however the pulse width of interference

signals are no rule.