Introduction

This section details how to determine what data may be read from addresses on the PLC of a Heidenhain machine.

There are at least three possible approaches: To request the information from the machine manufacturer, to read the tables directly from the HMI, and to read addresses from files extracted from the machine. The latter two are described below.

Generally speaking, many addresses on an iTNC 530 are established by HEIDENHAIN, but may be supplemented by other data of interest. On a TNC 640 machine manufacturers have significantly greater leeway.

Topics covered in this section:

• Reading PLC Tables In the HMI
• Extracting Symbol Files from the HMI

Reading PLC Tables In the HMI

Identifying a Specific Memory Address

Specifics about PLC memory addressing is available from the machine manufacturer. Alternative one can view the PLC memory tables directly from the controllers. Generally this is a laborious process, as it entails perusing tables like the one shown below, but is efficient when the user knows where to look, perhaps to confirm the contents of an address of interest.

We will use the example of identifying the part count in the WORD table of an iTNC 530, but the same principle applies to other data.

Step 1: In the HMI, select the Programming and Editing operating mode.

Step 2: Press the MOD key.

Step 3: Enter the code 807667, then press ENT. (Note: If the default password does not work, use the correct password to proceed.)

Step 4: Scroll using the arrow soft-key until the “TABLE” function key appears at the bottom of the screen.

Step 5: Initially, the Marker table appears. Keep scrolling until you see 'W' (WORD). Switch to Decimal view and examine this table.

Step 6: Identify the counter either by matching the current known part count or by description. If the description isn't available, look for a number that matches the current count for reliability.

In the example provided, the part counter ("werkstueck zaehler" translates to "workpiece counter") is usually at location 20 in the WORD section for the iTNC 530, or 10 or 19944 for the iTNC 640.

If unsure whether the identified number is the correct parts counter—especially if it's not unique—note the address, increment the counter by creating another part, then check if the value at the same address has increased accordingly. For other metrics, exercise the machine to check that the value in the chosen address changes in a meaningful way.

Note that in the table, the left-most column in the table shows memory base addresses, while the top-most row shows offsets from these base addresses. The address of any given item in the table is equal to left-most column value + offset in the top column.

For instance, in the example above, the selected item is at address 20 (20 + 0). Conversely, the address holding the number 4625 is at address 136 (120 + 16).

Extracting Symbol Files from the HMI

On an iTNC 530 the address locations are usually mandated by HEIDENHAIN and are available through their technical documentation, but may be viewed in either of the two files MAIN_PGM.lst and MAIN_PGM.WLC, located in the \plc\BASIS\PROGRAMM folder.

On a TNC 640, by contrast, a process is required to extract and save a diagnostic file that describes succinctly which address contains what information.

Step 1: Generate and Save a Service File

In this step a collection of Service Files in .zip file form will be saved to the TNC:\service folder.

Open the Save service files dialog by entering the Errors page.

From there navigate to the Log Files page, and select “Save Service Files”.

Enter a name. A date and time will be appended to it automatically, so accepting the default name “service” is just fine.

Click OK. A progress dialog pops up. The process takes a little while.

Exit out of the Errors page completely by selecting End. The file has now been saved to disk.

Step 2: Move the Service File to an External Target

In this step the .zip file is moved to a folder from which it may be accessed directly, such as a USB flash drive or a public folder, and manipulated from there.

Enter Program Management and the file manager, select the file that was created. (Note that the name of the file named “service” in the “Save service file as…” dialog has been renamed to include the current date and time.)

Open image-20240223-193923.png

Select Copy.

Leave the “Copy file” popup in place, but disregard it; instead select the Folder Picker:

In the popup select the USB flash drive target directory, and click OK. The file is now saved to the USB flash drive or folder from where it may be accessed.

Step 3: Extract the Symbols List File

Once saved, access and extract the file symbol.lst file from the .zip archive created above, located in the SYS_/runtime folder:

Open image-20240223-195147.png

This file contains information about the locations of various metrics in PLC memory, and holds no proprietary information. Extract it from the .zip file and save it.

Interpreting the File Contents

Some of the names used in the symbol list may be difficult to understand, but many are elaborated on in the main PLC program stored in the file PLC:\plc\program\MainPgm.src.

On an iTNC 530 it is usually not necessary to extract a symbols file as the MainPgm.src is itself sufficient to determine PLC addresses.