IDEC FS1A Controller - Manual (Page 361)

LOGIC
5-313
Chapter 5
Dual channel dependent input
This function is for connecting safety devices with dual channel dependent action mechanisms,
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 switches or interlock
switches.
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 safety check signals from 2 drive circuits are correctly supplied to 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
ON
OFF
Input monitor error
detection time：∞s
Independent conditon
change in one input
Y
m
(Monitor output)
0.5s 0.5s
Ⅰ Ⅱ Ⅲ Ⅱ Ⅰ Ⅱ
ON
OFF
ON
OFF
ON
OFF
Ⅱ
Cance-
llation
SafetyOne changes to
Protection State after an input
monitor error is detected.
1Hz pulse signal is output from
corresponded monitor output.
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