Displaying runtime status and attributes for a Siemens S7 device

The Devices window displays the devices that are defined in the node. Runtime statistics will be maintained for each device that is in the Started state.

Displaying runtime statistics

To display the runtime statistics:

1. Select a device in the list of devices.
   The device’s operational statistics are displayed in the Status tab.
   

2. Select the Status tab. The following example displays the status panel associated with a Siemens S7 device.
   

   Parameter	Value
   Start Time (ms)	Length of time in milliseconds needed to start the device.
   Stop Time (ms)	Length of time in milliseconds needed to stop the device.
   Avg Queue Wait (ms)	Length of time in milliseconds device read/write requests spent in a queue waiting processing.
   Queue Depth	Number of items in the queue.
   Last Read	Timestamp of the last read request.
   Avg Read (ms)	Average millisecond length of time needed to perform the last 10 device reads.
   Last Write	Timestamp of the last write request.
   Avg Write (ms)	Average millisecond length of time needed to perform the last 10 device writes.
   Last Occurrence	Most recent time the error occurred.
   First Occurrence	Initial time the error occurred.
   Variable	The variable associated with the error occurrence.
   Status	The error code that was encountered.
   Ext. Status	An extended error code that was returned by the device.
   Repeats	The number of times the error has occurred between the Last Occurrence and First Occurrence.

Displaying attributes

The Siemens S7 devices will display additional attributes when they are in the Started state. To display these attributes:

1. Select a Siemens S7 device in the list of devices. The Siemens S7 device attributes are displayed in the Attributes tab.
   

2. Select the Attributes tab.
   The Attributes tab for the Siemens S7 device will display the attributes and their current values for the selected device:
   

   Parameter	Value
   PDU Size	Actual size in bytes of a Protocol Data Unit. This may be different than the value configured in the device definition.
   Structure Count	The number of structures defined in the device definition. A structure is a means by which a named variable is used to represent a particular address in the data block.
   Structure Member Count	The total number of named variable items defined within all structures.
   Total Variable Count	The total number of all readable and/ or writable variables represented on the device.
   Variable Count	The number of unique items defined on the device. These can be primitives, arrays or structures, but they only count as 1 item in the tree.

These attributes are shown to provide an indication of the amount of resources the device is consuming.