Siemens ERPC driver troubleshooting

The features and functions available in a node are controlled by the licenses that are installed in the node.

To verify that the Siemens ERPC driver license is installed:

1. From the Workbench left pane, expand the node whose license you want to check, and then select the Administration icon.
   
2. From the Administration window, select the Licenses tab.
   
3. Select the appropriate license. Details of the license appear on the tab.
   
4. View the Features column to identify the device driver.

If you do not see the correct license, or if the license is expired, you must request a license from your license key provider.

For information on how to install a license, refer to System Administration > Licenses.

 The Siemens ERPC driver is not part of this node's installation. The Siemens ERPC driver is installed as a package separate from the base product installation.

You may be working with different levels of nodes, each with different levels of support for devices. Ensure that this node is the one with support for Siemens PLCs.

For information on how to add the Siemens ERPC driver package, refer to System Administration > Packages.

 The Siemens PLC needs to be configured using the Siemens STEP 7 software. The complete description of this configuration is beyond the scope of this documentation.

Ensure that the IP address in the network settings is correctly configured for your network setup. There may be cross subnet issues depending on how the PLCs were configured.

Try using the Ping function on the Workbench Administration panel, Diagnostics tab for your node to see if that level of communication is successful.

The Siemens PLC may be configured to accept a limited number of connections from partners, such as the Siemens ERPC driver.

Review the PLC's configuration using the STEP 7 software for the number of concurrent connections that the PLC will accept. Review all applications, such as SCADA tools and HMI terminals that might be connected to the Siemens PLC.

The data blocks are not viewable through the Variables window in the Workbench.

The data blocks may not be defined in the PLC module. Use the Siemens STEP 7 software to define these data blocks in the PLC.
Ensure that the DB data blocks are defined correctly in the device definition.

The device representing the Siemens PLC may be configured to display Symbols only and not display the data blocks. Check the device definition in the Devices window in the Workbench.

A Device Protocol Error is returned when attempting to access (read or write) certain I/Q/M variables.

The maximum I/Q/M variable ranges are defined manually by the user in the device definition. Refer to Siemens ERPC device definition for information on how these ranges are defined. If the physical number of I/O points is less than the range specified then a Device Protocol Error will be returned when attempting to access data points outside the physical range.

A Device Protocol Error is returned when attempting to perform array writes on I/Q/M variables.

When writing Boolean data, only a single bit can be written at a time, the variable count must equal 1. If it does not, then the write will fail. Multiple bits can be written one at a time through separate write commands issued to the PLC.

Read failed: A Variable data overflow error is returned.

This is an issue with the manner in which strings are read and written from the PLC memory. When writing a string, the first two bytes of the string holds the string length. These two bytes are written to the first two bytes of the data block on the PLC. When reading back the string through the Siemens ERPC driver, the first two bytes are read first to determine the length of the string. If reading a portion of the string from a data point other than the first two bytes, an invalid length may be read resulting in an overflow error.

A deviceWISE trigger associated with a Siemens FB56 instruction does not execute when expected.

Use STEP 7 to check if the FB56 is activated.

Use the NCM diagnostics from STEP 7 to view information regarding the logical trigger.  A screen similar to the following will be displayed:

In the left pane of the screen, expand the ERPC trigger item.

It will show the name of the trigger as defined in deviceWISE. 

Under the deviceWISE trigger name, select the Trigger statistics item.

The panel will display information regarding when the trigger was executed.

Under the deviceWISE trigger name, select the Trigger status item.

The panel will display information regarding the configured variables to provide to the deviceWISE trigger when the FB56 instruction is executed.

Check all definitions as seen in STEP 7 and ensure they match with what has been defined for the deviceWISE trigger, including:

• Trigger name
• ID
• Config DB
• Variables

As deviceWISE items are defined and edited (Projects, Triggers, Devices, Transports, etc.), their definition is stored in an internal database.  Periodically, this deviceWISE database is checked for changes and a backup copy of the database is made in the c plug. In the event of an ERPC hardware malfunction, the c plug with this back up copy of the deviceWISE database could be restored into another ERPC.  This restore process includes the following:

• Use STEP 7 to set the replacement ERPC to factory defaults. 
• Install deviceWISE in the replacement ERPC.
• Place the original c plug into the replacement ERPC.
• When the replacement ERPC is powered up, deviceWISE will detect the new database and restore the copy from the c plug into the main file system.
• Temporary “emergency” deviceWISE licenses will be generated and usable for a short period of time.

Contact your license provider for replacement permanent license keys.

This section describes the error codes that you might encounter when using deviceWISE and the Siemens ERPC driver.

These error codes are available from the Devices window in the Extended Status column. The error codes are also referenced in the Exceptions Log.

When the system experiences an abnormal condition (such as a device failure, disconnect from a controller, or software error), an error code and extended error code are recorded in the Exceptions Log.

In the Devices window, the Status column will always be a generic error code that can tell you if the error is a communication error, a data error, or some other internal device error.  The Extended Status column provides the error code from the driver. These error codes can be basic deviceWISE error codes or specific to the Siemens driver.