
B–62073E/04
6. CONNECTION OF I/O UNITS TO
MACHINE INTERFACE
151
Input signals for the connection unit conform to a non–insulation type
interface. There are two input types: Direct current input signal A and
direct current input signal B.
(1)Direct current input signal A
Direct current input signal A is a signal sent to the CNC from the
machine, e.g., from a button, limit switch, relay contact, or proximity
switch.
(a) The contacts on the machine must meet the following
requirements:
Contact capacity: 30 VDC, 16 mA or more
Leakage current between contacts when the circuit is open: 1 mA
or less (Voltage: 26.4 V)
Voltage drop between contacts when the circuit is closed: 2 V or
less (Current: 8.5 mA)
(Including the voltage drop through the cable)
(b)Fig. 6.4.2 (a) shows the receiver circuit for the signal.
CNCMachine
Receiver circuit
Direct
current input
signal
+24 V
Filter and level
convention circuit
Receiver
output
signal
R
Logical 0 when the
contact is open
Logical 1 when the
contact is closed
Fig. 6.4.2 (a) Receiver circuit
Fig. 6.4.2 (b) shows the time specifications for the signal.
5 to 22 ms
Direct current
input signal closed
Receiver output signal
Logical 1
(18 V or more)
Chattering of 5 ms or less is ignored
(Signal) (Signal)
5 to 22 ms
Logical 0
(6 V or less)
Open
Fig. 6.4.2 (b) Width and delay time of the input signal
6.4.2
Input Signal
Regulations for the
Connection Unit