BECKHOFF M3120 - Manual (Page 3)

M3120 Incremental encoder 4x Beckhoff II/O-Lightbus
Date 20.10.94 Version 1.1 Page 3 of 14
1. Function description hardware
M3120
The periphery module M3120 establishes the connection of four incremental encoders for the
II/O-Lightbus system. It contains three separate power supplies for logic (5V) and pick off
power supply (5/15V) and the level adjustment from 15 V down to 5V. 5 V or 15 V encoder
can be connected to the incremental box M3120, either with or without complementary
channels.
All digital functions are integrated in four separate periphery controller (LCA circuit):
- 24 bit UP/DOWN counter with a limiting frequency of 1.25 MHz.
- Input "counter disable"
- 24 bit latch for counter position at zero impulse.
- Squareness decoder with adjustable 1, 2 or 4 times evaluation
- Selective computation of complementary signals (fewer interferences)
- Connection to the II/O-Lightbus with all functions:
addressing, interrupt, address counting, decrease transmission intensity,
cycle and error LED
- Read, set and activate commands for counter and zero impulse register via fibre
optic II/O-Lightbus