11 What Happens If …?
11.5 Functionality of the NET faulty
Control Relay easy800
11/11 MN04902001Z-EN
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Table 25: Reaction to missing sign of life signal on a NET station with or without a program.
11.5.2 Replacing a NET station
If you wish to replace a NET station NT2 - NT8 in a running plant, you should
take preparatory measures in order to ensure fault-free commissioning of
this NET station.
Example
In a network run with a baud rate of 250 KB, the NET station NT7 is to be
replaced.
If you are using a easy800 device as replacement that is still in its default
state and does not have a NET-ID, this device is not automatically integrated
in the network. Even connected to the power supply and the NET, the
LED NET remains off. It is then also not possible to load a program via the
easySoft-Pro programming software (Communication View -> Device list
box, NT7) into this replacement device.
The following procedure ensures fault-free commissioning of the
replacement device.
▶
Connect the easy800 replacement device to the supply voltage and
connect it at the same position to the NET as the device to be replaced.
▶
Switch the device display of all NET stations to Status display.
▶
Start the automatic con
fi
guration of the NET,
“Configuring NET”, page 94 . However, you can also do this via the
programming software. As an alternative to the automatic configuration,
you can also switch the supply voltage of the configured NET stations off
and on.
All NET stations in the NET configuration will temporarily switch to STOP.
Station with circuit diagram
NET station 1 detects the failure of a NET station 2 to 8 without a circuit
diagram:
Input values received via nI.., nR.., nQ.., nS.., nRN.. and GT.. are set to 0.
The output values for this NET station are not changed.
Station without circuit diagram
NET station with a NET ID 2…8 in
REMOTE IO mode
The output values Q01 - Q08 and S01 - S08 received from NET station 1 are
set to 0.
→
After the supply voltage is switched on, the other NET stations
and NET stations of type easy800 start up NET communication
at different speeds. When these different types are used on a
NET in mixed operation and are started simultaneously, a faster
starting NET station will set its diagnostics contact ID.. = 1 to
indicate a NET station of type easy800 as missing.
Solution: On “all other NET stations” delay the evaluation of the
diagnostics bit ID.. for the NET stations of type easy800 by
approx. 5 s by using the T function block (timing relay).