Precautions For Ac Input Modules - Toshiba V Series User Manual

3.2 Precautions for AC Input Modules

(1) The conditions to read the ON/OFF state of the input signals are as follows.
Input ON time ≥ ON delay time (OFF → ON)+Input reading cycle
Input OFF time ≥ OFF delay time (ON → OFFN)+Input reading time
The "input reading cycle" means the CPU module scan cycle for the refresh input, or
the execution interval of a direct input instruction when the instruction is used.
(2) When an AC output sensor is connected to the I/O module, due to the leakage
current from the sensor at OFF, there may be a voltage which exceeds the
maximum OFF voltage between the input terminals. This will make the CPU module
unable to read input OFF when the sensor is OFF. In the case, install a bleeder
resistor between the input terminals to lower the input impedance.
(An example of selecting a bleeder resistor R)
Input module IN653
Input voltage V=100Vac (50Hz)
When the voltage between input terminals is Vd at the switch OFF state (with no
bleeder resistor), the resistance (R) and the wattage (P) of bleeder resistor can be
selected as follows.
As a result,
Also, when the bleeder resistor is selected in the above manner, the load current at
the sensor ON state should be checked.
6F8C0836
AC output type sensor
Leakage current at OFF
Input impedance:15KΩ(50Hz)
OFF voltage: 30Vac
15[k ] × R 35[V]
×
15[k ] ＋ R 15[k ]
R ＜ 9 0 [k ] → R = 20 [k ]
2
(100[V])
P= (2.5 3 )
× ～
20[k ]
Sensor output load current
3.2 Precautions for AC Input Modules
Input module
Bleeder resistor
R
∼
V
＜ 3 0[V]
1.5[W]
≒
Ω ×
15[k ]
= ×
100[V]
+
Ω
15[k ]
R
=12[mA]
R
123
3