Ignition to Siemens tags

Hi all

I'm trying to display an indicator on my Ignition HMI and the source is a Siemens memory output. The output is %M0.4 (it's a bool alarm)

I've tried various configurations of the Ignition tags to get Ignition to read the tag from the controller but I'm not having any luck. There are comms because I have other tags reading but they are direct tags such as analog: [BMS Siemens 1200]MREAL36.0.

Ignition 7.9 and Tia Portal ver 15

Can you modify the program to map that boolean onto a DB? It's strange to have that type of memory being used in TIA Portal and I wonder if it blocks external access to those variables.

cardosocea said:

Can you modify the program to map that boolean onto a DB? It's strange to have that type of memory being used in TIA Portal and I wonder if it blocks external access to those variables.

Click to expand...

do you mean move it to an INT?

So i created a new INT tag and then moved a 1 to it from the Bool in the program; I readdressed the Ignition tag to reflect the new Siemens tag and it worked, I just had to reverse contacts to get it to move a 0 when there is no true condition.

I'm looking here: https://docs.inductiveautomation.com/display/DOC79/Siemens

Area: Flag
Datatype: Boolean
Offset: 4

So your address in ignition should be MB4.

Have you tried that yet?

PreLC


Yes, that was one of the first variations I tried. I have that document as well. Either way, creating an INT addressing it with 1 or 0 (via a MOV) seemed to work.

toddp65 said:

do you mean move it to an INT?

Click to expand...

No. An INT is a variable type (as is boolean). An M address is an address in memory (which Siemens has consistently told people not to use anymore). A DB is a dedicated address space created by the programmer to hold relevant data tigether.

Think of a DB as the RSLogix500 B,N,F, etc... files.

So you could either look for a DB that had empty space in it (be it a Bool or INT) and map that bit into that space and read it from your Ignition instance.

Looking at Ignition's documentation you actually needed to use MX0.4 to read that bit into Ignition. Did you try that variation?

cardosocea said:

No. An INT is a variable type (as is boolean). An M address is an address in memory (which Siemens has consistently told people not to use anymore). A DB is a dedicated address space created by the programmer to hold relevant data tigether.

Think of a DB as the RSLogix500 B,N,F, etc... files.

So you could either look for a DB that had empty space in it (be it a Bool or INT) and map that bit into that space and read it from your Ignition instance.

Looking at Ignition's documentation you actually needed to use MX0.4 to read that bit into Ignition. Did you try that variation?

Click to expand...

Wow I completely made the incorrect Flag+boolean->MB connection.
Definitely should be MX0.4, if it still doesn't work, then it's a different issue.

It's been too long since I've used these, but aren't they labelled just M4.0 or something similar in the program? Perhaps that's the way to get them?

The other thing that just dawned on me is that the MB0 byte is at times used for diagnostic or timer, so it may well be overwritten in the program (I assume not, but doesn't hurt to check if that setting is on).

The only other thing I can think of is if TIA protects M bits from being accessible from the outside or if they're stored as the default DB's in the system (which Ignition can't get to unless you disable optimization).

If you can change the PLC program, just map the M bit to a non optimised DB location and be done with it.

cardosocea said:

The only other thing I can think of is if TIA protects M bits from being accessible from the outside or if they're stored as the default DB's in the system (which Ignition can't get to unless you disable optimization).

Click to expand...

No you can access the 'legacy' addresses from outside, also via OPC. I.e. Merker addresses, S5Timers, S5Counters.
It is only discouraged to use the legacy addresses. I only use them for quick-and-dirty program changes..
There are a few system merker bits (Always on, always off, 1st scan, clock bits..) that you can access and which you should only read, but nothings stops you from writing to them.

MX0.4 should work, we use siemens with ignition for most of our projects. Instead of using the ignition siemens driver you should look at enabling OPC UA server on the CPU, this will allow you to use 'optimised db' and browse tags.