SLAVE READING FROM MASTER EVEN AFTER PLCS DISCONNECTED

Have you really a Master/Slave procedure?
You have set one LOGO! in the slave modus?

Or mean you Client/Server?

Tabindah

I'm sorry I did not understand your suggestion. Both my PLCs have their own programs. The Slave PLC, [which is also defined as master in system] reads some values from the other PLC. If the master PLC is disconnected the salve plc should show 0 over there but it still shows the last readings from master. 

If I try to configure my slave plc as SLAVE it says u can only download it if is configured as Master, hence both PLCs are defined Master only.

You have no Master/Slave connection, but a Client/Server connection, if in both LOGO!s runs a program.

By Master/Slave has the slave LOGO! no program. The slave in then a dumb PLC and only provides the Master with its hardware.

The LOGO! detects different communication errors differently, sometimes they are not recognized at all.

1.) Case: Client LOGO! is switched to STOP.
Server LOGO! detects this and all bits in VM memory (VB0 to VB850) would be set to low.

2.) Case: Client LOGO! loses the power supply.
Server LOGO! does not recognize this and all bits in VM memory (VB0 to VB850) keep their state.

3.) Case: At the client LOGO! the plug of the Ethernet cable is removed.
3.1) LOGO!s are directly connected.
Server LOGO! detects this, but all bits in VM memory (VB0 to VB850) retain their state. This error can be queried via a network input with the “Ethernet error” diagnostic function.
3.2) LOGO!s are connected via a router.
Server LOGO! does not recognize this and all bits in VM memory (VB0 to VB850) keep their state. This error cannot be queried via a network input with the “Ethernet error” diagnostic function.
It is recommended to program a life bit query in both LOGO!s.

First of all:
I know of no method to set all bits in the user-usable VM memory (VB0 to VB850) to low in the event of a communication error.
This only works individually for each bit or word used.

Attached is a small network project that shows you the diagnostic query for the “Ethernet link error”.

In addition, the generation of a life bit and its evaluation. A signal is generated in the client LOGO!, which changes state every second. The signal is sent to the server LOGO!. There it is asked whether it is either HIGH or LOW for longer than 1.5 seconds. If this is the case, communication is interrupted. At the same time, the received life bit is sent back unchanged to the client LOGO! and evaluated there.

Tabindah

Extremely Sorry for the trouble, but the attached file does not have any program. it just has 2PLCs connected but there is no program in FBD or LAD

You have deleted your post.

That not correct what you wrote.

The network project has 2 LOGO!s and every LOGO! has a program.

You must make a double click on every LOGO! and opens the programs.

See attached screenshot.