Table 10-4 Interconnecting Digital Output Modules With/Without Diodes - Siemens SIMATIC S7-400H System Manual

Interconnection using external diodes <-> without external diodes
The table below lists the redundant digital output modules you should interconnect using
external diodes:
Table 10-4
Module
6ES7 422–7BL00–0AB0
6ES7 422–1FH00–0AA0
6ES7 326–2BF01–0AB0
6ES7 322–1BL00–0AA0
6ES7 322–1BF01–0AA0
6ES7 322–8BF00–0AB0
6ES7 322–1FF01–0AA0
6ES7 322–8BH01–0AB0
6ES7 322–5SD00–0AB0
Information on wiring the diode circuit
● Suitable diodes are, for example, those of the series 1N4003 ... 1N4007, or any other
● It is advisable to separate the chassis ground of the module and load ground. There must
Using analog input modules as redundant I/O
You specified settings for the following parameters when you configured the analog input
modules for redundant mode:
● Tolerance window (configured as a percentage of the end value of the measuring range)
● Discrepancy time (maximum time in which the redundant input signal can be outside the
● Applied value
The system verifies that the two read-in analog values are within the configured tolerance
window. If they are, the applied value is written to the lower data memory area of the process
input image. If there is a discrepancy and it is the first, it is marked accordingly and the
discrepancy time is started.
S7-400H
System Manual, 09/2007, A5E00267695-03
Interconnecting digital output modules with/without diodes
diode with U >= 200 V and I_
_r
be equipotential bonding between both.
Two analog values are considered equal if they are within the tolerance window.
tolerance window)
An error is generated when there is an input value discrepancy after the configured
discrepancy time has expired.
If you connect identical sensors to both analog input modules, the default value for the
discrepancy time is usually sufficient. If you connect different sensors, in particular
temperature sensors, you will have to increase the discrepancy time.
The applied value represents the value of the two analog input values that is entered in
the user program.
with diodes
X
-
X
X
X
X
-
-
X
>= 1 A
F
Using I/Os in S7-400H
10.5 Connecting redundant I/Os
without diodes
-
X
X
-
-
X
X
X
-
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