IDEC FS1A Controller - Manual (Page 127)

5-86
Dual channel NO/NC input
This function is for connecting safety devices with dual channel NO/NC mechanisms, such as
non-contact interlock switches. As shown in Fig. 5-5, this function is comprised of a dual channel
input receiving circuit (X
n
, X
n+1
), a drive circuit (T
n
, T
n+1
), and a functional output (I
n
). Because
safety devices comprised of NO and NC contacts are connected, during normal operation, 1 of
the dual channel inputs is ON while the other is OFF.
Fig. 5-5 Circuit for dual channel NO/NC input function
Connects to
Safety devices with NO/NC contacts, such as a non-contact interlock switch.
Note: This cannot be connected to a safety light curtain or any other safety solid state output.
Description of operation
The operation timing is described in Fig. 5-6.
Ⅰ When a safety check signal from 1 of the 2 drive circuits (T
n+1
) is supplied to the
corresponding receiving circuit (X
n+1
) and the other receiving circuit (X
n
) is OFF, the output
is turned ON. (Ex. Guard is closed.)
Ⅱ When a safety check signal from 1 of the 2 drive circuits (T
n
) is supplied to the corresponding
receiving circuit (X
n
), and the other receiving circuit (X
n+1
) is OFF, the output is turned OFF.
(Ex. Guard is opened.)
Ⅲ If safety check signals are not supplied correctly to the receiving circuits, due to an error in
the safety device or input circuit, the output is turned OFF immediately. Status of any
detected error is displayed on the error LED, input LEDs and monitoring output. (Ex. Fault in
the non-contact Interlock switch)
X
n
X
n+1
I
n
Input monitor
error detection
time：Max.0.5s
①
② Independent conditon
change in one input
The monitor output
corresponding to the input
which occur error becomes
pulse output (1Hz).
0.5s 0.5s
Ⅰ Ⅱ Ⅲ Ⅱ
Y
m
(Monitor output)
SafetyOne changes to the
Protection after an input
monitor error is detected.
Ⅱ
0.5s 0.5s
Ⅰ Ⅲ Ⅱ
Cance-
llation Cance-
llation
②
SafetyOne
changes to the
Protection after
an input monitor
error is detected.
ON
OFF
ON
OFF
ON
OFF
ON
OFF
Fig. 5-6 Operation timing of a dual channel NO/NC input function
X
n
T
n
X
n+1
T
n+1
I
n
Safety device
Dual Channel
NO/NC