HEIDENHAIN PWM 20 - Manual (Page 238)

November 2014 Interface description 239
Examples of
encoders ROQ 425 programmable
Code signals
Incremental signals 1 Vpp (“Incremental signals 1 Vpp” on page 212)
Fault detection
signal UaS
Programming
inputs
Interfaces Serial in the SSI (fir tree) or synchronous-serial right-
aligned (programmable) data formats
Data input Differential line receiver according to EIA standard
RS 485 for the signals CLOCK, CLOCK, DATA and
DATA
Data output Differential line driver according to EIA standard
RS485 for DATA and DATA signals
Signal level Differential voltage output
> 2 V (EIA standard RS-485)
Code Gray code or binary code (programmable)
Direction of rotation Increasing code values with clockwise or
counterclockwise rotation, viewed from flange side
(programmable)
1 square-wave pulse UaS (HTL) Improper function = LOW
Proper function = HIGH
Direction of rotation and reset
Inactive LOW < 0.25 x Up or input open
Active HIGH > 0.6 x Up
Switching time t
min
> 1 ms