"""That is impossible!
The method "b is direction, a is clock" IS faulty."""

Erik ,
of course there is a GAL16v8,which produce up/down and clock signals from AB signals from encoder

the counter is functioning very well without a noise source
the problem is when i want to drive a motor with an inverter
the counting flip flops in 4029 chips are set randomly all of a sudden without a count pulse from encoder

i have connected the earth to the inverter but there is no help

the only connection to the inverter is the output of the DAC to give speed command to the inverter

when everything is OK i will be able to position control the motor or whatever is connected to the motor shaft

thanks for any help