FX Series High Speed Counter

[aldarin]

Hi, I am trying to count pulses from an encoder attached to a dc motor. I need to find the position of a part excited by the motor linearly moving on a table by counting the encoder pulses . I have looked at the fx series programming manual but couldn't understand anything. I need an example to get a picture of this or someone to clearly explain the operation. I would really appreciate for your help. Best wishes.

[Colin Carpenter]

The attached text file is a MEDOC listing that reads the pulses from a shaft encoder into X0 and X1 (Phase A and B) and uses high speed counter C246 for Phase A. You need to know the relationships between the high speed counter inputs and the high speed counters for your particular PLC. This particular application was a pneumatic ram carrying a printer head which had to fire date codes onto 2 pot lids on a rotary filling machine. ENCODER.txt

[Goody]

AS Colin says - you will have to use a HSC (High speed counter) These are special counters and if you use C246 it looks at pulses on X0 but X0 does not show in your logic. M8000 is an always on bit so you use this to enable C246 -| m8000|------(C246) K10000 When pulses are seen at X0 c246 will count up, when it reaches 10000 C246 will close an N/O contacts it has. Be warned, it will count past its preset. Also note, it is a 32 bit counter and so to compare or move the value you will have to use double words You can reset the counter with RST C246 - it will not automatically reset.

[aldarin]

Hi Colin and Goody, Thanks for your response, it helped me a lot. Greetings.

[Abiram]

hello,right now i am doing a project to calculate the speed of a conveyor using a encoder,i am using fx5u plc and the sofware is gx works 3 which is new,do i need to configure the high speed counter or can i simply use the high speed counter,because in gxworks 3 it is having some option to enable the high speed counter  special register to store current value of the pulse ,help me

[Nguyen Duy Nghia]

You just have to read the value of the responsive Counter ( Hight Speed counter: C246 to C250)