Re: No encoder pulses detected on VSD-E 160 drive. Ideas?
Can you measure what the voltage is on each of the 4 encoder inputs with the encoder unplugged ? What voltage are they sitting at ?
If your using a singe ended encoder and you say it doesn't matter if the unused pin just sits unconnected, then what is the point of a differential encoder ?
Most encoder inputs have a pull up resistor to help the encoder drive the long cable, also there usually is a RC filter before the receiver chip, rarely would it just go straight into the chip.
If there is a pullup on a unused pin on a differential receiver, it won't work because its expecting the 2 wires to be a compliment of each other HL or LH, but if its unconnected you get HH and LH, so why would it work ? On the 75157 driver (like i use) you need to have the ununsed input sitting at 1/2 voltage (2.5 volts). (You should try this before probing the board, as you may accidently short something out )
It also could be a bad solder joint, but examining with a magnifier will rule this out.
Larry
Manufacturer of CNC routers and Viper Servo Drives
www.LarkenCNC.com and www.Viperservo.com