750-421 [2 DI DC 24V 3.0ms, High-Side Switching, Diagn.] • 7
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WAGO-I/O-SYSTEM 750
I/O Modules
2 I/O Modules
2.1 Digital Input Modules
2.1.1 750-421 [2 DI DC 24V 3.0ms, High-Side Switching, Diagn.]
2-Channel Digital Input Module DC 24V 3.0ms,
2- or 3-conductor connection; high-side switching, Diagn.
2.1.1.1 View
01 03
+ +
-
-
13 14
C
D
B
A
02 04
- +
DI 2
24V
0V
DI 1
U 2
U 1
V
V
750-421
Power jumper contacts
Data contacts
Status DI 2
Status DI 1
Error DI 2
Error DI 1
Fig. 2.1.1-1: 2-Channel Digital Input Module 750-421
g042100e
2.1.1.2 Description
The digital input module 750-421 receives control signals from digital field
devices (sensors, switches, etc.) and supplies a short-circuit proof voltage to
the sensors.
The module is a 2- to 3-conductor device and has two input channels. Two
sensors may be directly connected to the module.
Two 3-conductor sensors may be directly connected to UV1, 0 V and signal
input DI 1 or UV2, 0 V and signal input DI 2.
Each sensor can be supplied separately over the outputs UV1 and UV2.
Each input module has an RC noise rejection filter with a time constant of
3.0 ms.
The status of the input channels is indicated via status LEDs. In addition, a red
error-LED will show if there are any short circuit to ground in either channel.
In case of a short circuit, one error bit (bit 2 or bit 3) is assigned to every
channel in the input data process image.
By means of this bit the supervisory
control can detect the error.