IDEC FS1A Controller - Manual (Page 125)

5-84
Dual channel dependent input
This function is for connecting safety devices with a dual channel dependent action mechanism,
such as an enabling switch. As shown in Fig. 5-3, this function is comprised of a dual channel
input receive circuit (X
n
, X
n+1
), a drive circuit (T
n
, T
n+1
), and a functional output (I
n
). The difference
from dual channel direct opening input, is that the dependency of the 2 inputs is monitored with
the dual channel dependent input function, but the dependent time is infinite.
Fig. 5-3 Circuit for dual channel dependent input function
Connects to
Safety devices with a direct opening mechanism, such as emergency stop switch or an interlock
switch.
Safety devices with a contact dependent mechanism, such as an enabling switch.
Note: This cannot be connected to a safety light curtain or any other safety solid state outputs.
Description of operation
The operation timing is described in Fig. 5-4.
Ⅰ When the safety check signals from the 2 drive circuits are correctly supplied to the 2 input
receiving circuits, the output is turned ON. (Ex. Guard is closed.)
Ⅱ When the safety check signal to either of the receiving circuits is turned 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 a detected
error is displayed by the error LED, input LEDs and monitoring output. (Ex. Fault in
Interlock switch or wiring error)
X
n
X
n+1
I
n
Input monitor error
detection time：∞s
①
② Independent conditon
change in one input
SafetyOne changes to the
Protection State after an input
monitoring error is detected.
The monitor output
corresponding to the input
which occur error becomes
pulse output (1Hz).
0.5s 0.5s
Ⅰ Ⅱ Ⅲ Ⅱ Ⅰ Ⅱ
Y
m
(Monitor output)
Ⅱ
Cance-
llation
ON
OFF
ON
OFF
ON
OFF
ON
OFF
Fig. 5-4 Operation timing of a dual channel dependent input function
X
n
T
n
X
n+1
T
n+1
I
n
Safety device
Dual Channel
Dependent