Hi,

in addition to the screenshot, program it like shown in this FAQ. So with e seperate network (or code) to move the status value into another tag. Otherwise its not good for monitoring as it is overwritten.

How do you evaluate the status of system blocks in STEP 7 (TIA Portal)?

You can also configure a trace in addition to that.

regard

sancruz

Hi

In addition to all other you can do the following:

in both data sets add a handshake bit

on your side invert incoming handshake before sending
on other side copy incoming handshake to data which is sent back to your side

monitor with timer if handshake is changing (i.e. reset timer on handshake change)

if it stops changing for a given time flag an error.

this will monitor if communication is working

side A (I = inputs from side B; Q = outputs to side B)
BTmp:=(I_HANDSHAKE AND Q_HANDSHAKE) OR (Q_HANDSHAKE=0 AND I_HANDSHAKE=0);
Q_HANDSHAKE:=NOT I_HANDSHAKE;

Timer (TON): use inverted BTmp as a start condition. if timer output goes high there is a communication error.

side B (I = inputs from side A; Q = outputs to side A)
BTmp:=(I_HANDSHAKE AND NOT Q_HANDSHAKE) OR (Q_HANDSHAKE AND NOT I_HANDSHAKE);
Q_HANDSHAKE:=I_HANDSHAKE;

Timer (TON): use inverted BTmp as a start condition. if timer output goes high there is a communication error.

Off topic (mostly / probably):

Think of the term "HANDSHAKE" as "Watchdog" if that helps you understand it better.