encoder to measure motor speed.how to specify the direction?

[m_mansour2005]

measuring motor speed

i've an optical encoder to measure the motor speed
2 wires o/p from this sensor
1stwire>>>>>to count pulses
2nd wire>>>>specify the direction right or left


i can count pulses.
sensor has no name.i try to know how to specify the direction but i can't .
any one know how those sensors work?? how to specify the direction?? i think all types of this sensors has one idea. any one know it?

 

[trekkytekky]

motor speed encoder

I assume you have a quadrature encoder. If two counters are placed on both wires simultaneously the count will be within +/- 1 if this is true.

The two clock streams are phase shifted by 90 degrees. In X1 mode you use A clock to count and the B clock to determine direction. On the rising edge of the A clock if B is Low we count in one direction (say Up) else if on the rising edge of the A clock B is High we count in the opposite direction (down). There are other modes X2, X4. Just google them.

 

[m_mansour2005]

encoder motor speed

thanQ i will test and reply

 

[m_mansour2005]

motor encoder

practical questions???
after encoder testing...
this is the result

turn right
wireA wireB
0 0
0 1
1 1
1 0

turn left
wireA wireB
0 0
1 0
1 1
0 1

although wireA -0011- from 0 to 1 count as pulse & from 0 To 0 also count as pulse.

i think from 0 to 0 >>>> convert from 0 to 1 to 0 rapidly . 1 senses only by timer0 but can't be seen by a LED for example?

the question?
what's the optimal way to specify the direction???

 

[trekkytekky]

measuring speed from encoder pulses

001100110011001100110 <--A (Rotating right)
011001100110011001100 <--B

011001100110011001100 <--A (Rotating left)
001100110011001100110 <--B

If all you are after is the direction, use something like a D Flip Flop, connect A to Clock, B to Data. On Rising of A edge it will latch the B clock (Direction). giving a Q state output of that direction updated on every rising edge of A clock. This should be implemented as an IC package or FPGA/CPLD due to speed. Seems a waste not to use the positioning / speed data as well, but if your application doesn't require it...

 

[similor]

measure motor speed

Maybe u can can try to use the hall sensor.There is a mode used in the BLDC motor.It can be test the speed and direction.