Discrete Input and Output Function (8 Input 12 Output)
 
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Description
The Discrete Input and Output (Discrete I/O) is a 24 Vdc function connected using a 28-pin terminal block (BMXFTB28x0). It is a positive logic function where the 8 input channels receive current from the sensors (sink) and the 12 output channels provide current to the pre-actuators (source).
The Discrete I/O function is available on the following PLC:
General Input Characteristics
The following table shows the general input characteristics of the Discrete I/O function:
Characteristic
Description
Value
Nominal input values
Voltage
24 Vdc
Current
2.4 mA
Threshold input values
At 1
Voltage
≥11 V
Current
>2 mA for U≥11 V
At 0
Voltage
≤5 V
Current
≤1.5 mA
Sensor supply (including ripple)
19…30 V
Input impedance
At nominal U
10 kΩ
Sensor supply monitoring threshold
OK
>17V(Typical)
Fault
<8V(Typical)
Response time
Disappearance/appearance
4 ms<T<5 ms
IEC 61131-2- Edition 2 (2007)
Type 3
Reverse polarity
Input
Provides an external fuse to the sensor 24 V.
2-wire/3-wire proximity sensor compatibility
IEC 947-5-2
Dielectric strength
Between PLC bus and field sides
1,500 Vdc for 1 minute
Between input and output groups
500 Vdc
Resistance of insulation
>10 MΩ (at 500 Vdc)
Type of input
Current sink
Paralleling of inputs
No
Sensor voltage monitoring threshold
No
Sensor power supply (8 inputs on)
Typical
30 mA
Maximum
35 mA
24 V sensor power supply (excluding load current)
Typical
8 mA
Maximum
10 mA
24 V sensor power supply consumption@25 °C (all channels OFF)
8 mA
24 V sensor power supply consumption@25 °C (all channels ON)
30 mA
WARNING
LOSS OF INPUT FUNCTION
Do not implement the voltage over maximum limit value.
Failure to follow these instructions can result in death, serious injury, or equipment damage.
Input Fuses
Fuse
Value
Internal
None
External
1 fast blow fuse of 0.5 A for the input group
CAUTION
LOSS OF INPUT FUNCTION
Install the correct rating and type of fuse.
Failure to follow these instructions can result in injury or equipment damage.
General Output Characteristics
The following table shows the general output characteristics of the Discrete I/O function:
Characteristic
Description
Value
Nominal values
Voltage
24 Vdc
Current
2 A
Limited values
Maximum voltage
19…30 V
Current/Channel
2.5 (1)
Current/12 channels
10 A
Power of tungsten filament lamp
Maximum
60 W
Leakage current
At 0
<0.5 mA
Voltage drop
At 1
<1.2 V
Load impedance
Minimum
12 Ω
Response time(2)
<1.2 ms
Frequency of switching to inductive load
0.5/LI² Hz
Paralleling of outputs
Yes (maximum of 2 channels and total 4 A) (3).
Built-in protection
Against inversions
Yes, by inverted diode(4).
Against short circuits and overloads
Yes, internal current limiter will limit output transience current at 7 A after internal over-temperature is detected
Pre-actuator voltage: monitoring threshold
OK
>19 Vdc (max.)
Fault
<14 Vdc (typ.)
Pre-actuator voltage: monitoring response time
On appearance
2 ms<T<4 ms
On disappearance
9 ms<T<11 ms
24 V pre-actuator consumption (excluding load current)
Typical
26 mA
Maximum
35 mA
Dielectric strength
Between PLC bus and field sides
1,500 Vdc for 1 minute
Resistance of insulation
>10 MΩ (at 500 Vdc)
(1) 2.5A for ambient temperature under 60°C; 2A for ambient temperature from 60°C to 70°C
(2) All outputs are equipped with fast demagnetization circuits for electromagnets. Electromagnet discharge time < L/R.
(3) Users have to control the two parallel channels simultaneously to avoid overload on one channel.
(4) Provide a 12 A fuse to the +24 V pre-actuator supply.
WARNING
LOSS OF OUTPUT FUNCTION
Do not implement the voltage over maximum limit value.
Failure to follow these instructions can result in death, serious injury, or equipment damage.
Output Fuses
Fuse
Value
Internal
None
External
1 fast blow fuse of 12 A for the output group
CAUTION
LOSS OF OUTPUT FUNCTION
Install the correct rating and type of fuse.
Failure to follow these instructions can result in injury or equipment damage.