PLCSIM Advanced

PLCSIM Advanced

If you are working with Siemens S7-1500 PLCs and TIA Portal TIA Portal , you can emulate your target PLC using PLCSIM Advanced, which then can be connected with Automation Connect. The tool identifies both running PLCSIM Advanced instances as well as previously configured ones stored in the PLCSIM Advanced "Virtual SIMATIC Memory Card" directory. When selecting a stored but not running project, Automation Connect will automatically start and load the selected PLCSIM Advanced instance (see figure Figure 22).

Figure 22: Selecting and starting PLCSIM Advanced instances

Before connecting to a PLC instance, you can select the variable scope that will be loaded / displayed. Global PLC In- and Outputs are always included, PLC DBs and Markers can be optionally included by checking the matching checkboxes in the PLCSIM Advanced tab. In addition you can decide if Drive Control Telegram WORDS (Status WORDs, Control WORDs etc.) should be displayed and handled as single variables of type WORD (unsigned 16-bit integer) or split to 16 single Boolean bits (see figure Figure 23).

Figure 23: PLCSIM Advanced controls

After the PLCSIM Advanced instance has started and switched to run mode, you will be presented with a new dialog with all available variables. The variables are organized in a tree view with e.g. a separate node for each Technology object. If the number of loaded variables exceeds a defined number, Automation Connect will propose limiting the variables to the global In- and Outputs. The limit can be defined in the PLCSIM Advanced settings (See figure Figure 22).

Here you can select specific variables (or complete nodes) and drag and drop them into the list below. After accepting the selection by pressing the OK button they will be transferred to the PLCSIM Advanced interface tab (see figure Figure 23).

Figure 24: Selection of relevant variables in PLCSIM Advanced

Acyclic Communication

In contrast to the native Cyclic communication between the Profinet devices, Acyclic data is sent only when it is needed without creating a permanent communication load. It is useful for infrequent or for very large data transfers (e.g. writing and reading parameters, status information or other metadata), but takes significantly longer than the cyclic transfer.

Acyclic I/O data is defined by the Data Records, exchanged with the RDREC (SFB52) and WRREC (SFB53) function blocks and initiated by the master SIMATIC controller. A read job always starts with a write job which informs the addressed device (defined by 'HardwareID') which values are to be determined ('RecordID'). The actual read job is then performed. An example from the 'function block manual: Control SINAMICS with SIMATIC S7" is displayed in figure Figure 25:

Figure 25: Function block example

PLCSIM Advanced supports this Acyclic Data Exchange on the API level so that registered 3rd party applications can access read/write requests initiated by a PLCSIM Advanced PLC instance. Both request types need to be initially registered with a defined callback method, which will be invoked in case of an outgoing RDREC or WRREC call; for a write request the API call already includes the DataRecord values. After processing the events the user application needs to acknowledge the request; for a read request the user application needs to include requested the DataRecord values on acknowledgement. (See table Table 1 and figure Figure 26).

SFB	Name	API method (alarm)	API event for triggering the SFB
52	RDREC	ReadRecordDone	OnDataRecordRead
53	WRREC	WriteRecordDone	OnDataRecordWrite

Figure 26: PLCSIM Advanced API acyclic events

While this event-based mechanism represents the PLC acyclic communication relatively well, neither Simcenter Amesim nor Automation Connect natively support this, but only offer cyclic data exchange with a fixed and defined number of variables. Therefore, the acyclic DataRecord information are translated to cyclic I/O variables and added to the setup in advance, resulting in following variables for each recipient:

• 4 x BOOLEAN Flags: to forward and acknowledge incoming read / write requests

• 2 x INTEGER IDs: to define the addressed device / record of incoming requests

• n x BYTE buffers: to transfer the read / write Data (defined as the maximal transferred data)

• 2 x INTEGER Data lengths: to store the actual requested data length

Note that especially the last part will create a heavy overhead of variables for large DataRecords requests. As those variables need to be listed, connected and exchanged with all involved systems in each cycle, this can negatively impact on the overall system performance.

The resulting setup for a DataRecord write request can be seen in figure Figure 27 (Read requests work the same way, but with the data buffer (Byte[n]) set by the FMU and forwarded back to the PLC). DataRecords need to be initially defined by the recipient device ID and the maximum in- and output data buffer length. The resulting variables will be added as 'virtual' variables to the PLCSIM Advanced Interface tab in Automation Connect.

Figure 27: Implementation of the acyclic – cyclic data translation in Automation Connect

To add (or remove) the necessary Datarecord information (recipient device ID, In-/Output buffer length), additional control buttons have been added in the Automation Connect UI. As seen in figure Figure 28, the PLCSIM Advanced interface tab now offers a Control field 'Acyclic Data' with the two buttons [+] and [-] to add / remove DataRecord definitions. These buttons will open another sub-control for entering / selection of all necessary information.

Figure 28: Automation Connect Acyclic Control Dialog

After defining such a DataRecord, AMC will automatically add all relevant variables. In the example above with maximum 128 bytes to write and 64 bytes to read, there will be a total of 200 variables added:

• 64 x BYTE Input read buffer variables

• 128 x BYTE Output write buffer variables,

• 2 x BOOL Input read / write request 'Finished' feedback

• 2 x BOOL Output read / write request 'Request' flags

• 2 x INT Output read / write request Record ID

• 2 x INT Output read / write request data length

The variables always start with the user defined recipient device ID ("DR" + ID), followed by the linked request direction ("Read" / "Write") and ending with the description. The data buffer itself is displayed as byte variables and enumerated according the array index ("DataByte[" + index + "]") (see figures Figure 29 and Figure 30).

Figure 29: Acyclic variables added to the PLCSIM Advanced variables

Figure 30: Acyclic variables listed in the 'Variable Mapping' tab in Automation Connect

Settings

The Automation Connect PLCSIM Advanced interface offers following global settings:

Figure 31: Automation Connect PLCSIM Advanced settings

• Include DB, Include Marker, Split Telegram Words: Identical to the checkboxes in the PLCSIM Advanced tab. See explanation above.

• Max Selectable Variables: Limit for loading / displaying variables in the selecion dialog. Projects with more variables will generate a warning and require additional confirmation.

• Auto Connect Compare Only Names: This option influences the symbolic comparison for auto connecting with PLCSIM Advanced variables in the Variable Mapping tab (see chapter Variable Mapping tab). If disabled, Automation Connect will compare the name including the complete structure path (e.g. "DB1.UDT1.Name"). If enabled, Automation Connect will only check with the variable name.

• Sync Mode: This option defines the sync mode for PLCSIM Advanced. See the PLCSIM Advanced manual for more details. Note that the synchronization is by default always time-based; The different modes only define where PLCIM Advanced will stop so that Automation Connect can analyze and synchronize with the PLC system time.

• Sync PIP: This option lets you alternatively synchronize to specific process image partition (PIP). If a positive number is entered (as well as 'SingleStep' mode selected above), Automation Connect will disregard the PLC system time but instead trigger one PIP cycle step regardless of the actual elapsed time. This option offers a more stable bus-synchronization, but requires the user to manually set the correct matching cycle time in the synchronization mode (see chapter Controlling a synchronized simulation).

• Auto Acknowledge Undefined Acyclic Requests: This option will automatically acknowledge all incoming acyclic read- or write requests (RDREC / WRREC) for undefined devices. In case of read requests an empty byte-array according to the requested data size will be delivered (see chapter Acyclic Communication for more information).