6. CONNECTION OF I/O UNITS TO
(2)Direct current input signal B
Direct current input signal B is a signal sent from the machine to the
CNC and used at high speed.
(a) The contacts on the machine must meet the following
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 (c) shows the receiver circuit for the signal.
Filter and level
Fig. 6.4.2 (c) Receiver circuit
As shown in Fig. 6.4.2 (c), the common voltage for the connection
unit can be selected from +24 V and 0 V by the wiring on the
(a) To use the connection unit with the +24 V common voltage
. Logical 0 when the
transistor is off. Logical 1 when the transistor is on.
(b)To use with the 0 V common voltage
. Logical 1 when the
transistor is off. Logical 0 when the transistor is on.
Fig. 6.4.2. (d) shows the time specifications for the signal.
2 ms max
(18 V or higher)
(6 V or higher)
2 ms max
(For +24 V common)
(6 V or lower)
(18 V or lower)
(For 0 V common)
Fig. 6.4.2 (d) Width and delay time of the input signal