FS-8707-09 – Logger Driver

Driver Version: 1.01

Document Review: 2

FieldServer Driver – Serial or Ethernet


Logger Driver



The Logger Driver acts as a data logger for the Fieldserver.  The driver copies a single value from a source data array to a destination data array. Before insertion in the destination, the elements in the destination array are shifted right one element. Thus a FIFO buffer is created in the destination array. The timestamp of each logged data value is also recorded in a data array and the file.  The configurations are set up so that the data array and timestamp array sizes are the same.

Since the Logger driver only manipulates the FieldServer’s internal data arrays, it is not connection specific, and can be used in both Serial and Ethernet applications.  However, certain connection and node related values are expected as input parameters in order for this data logger driver to be enabled.  These are indicated as dummy values.

The Logger driver can also be used to record data to a secondary storage file.  As data from a single point is collected, it is appended to a data file specified in a configuration.   Periodically, as the secondary storage becomes full, the driver will truncate the oldest records from the files leaving the most current data.  The truncated file sizes are determined by the FIFO buffer “length” fields specified in the configuration files. The maximum size of a FIFO buffer length is 400 data array elements.

On startup, the logger driver examines all configurations, reads the specified data storage files, and loads the data values/timestamps into the specified FIFO buffers.  In this way, logger data can be made persistent during a Fieldserver shutdown.


Formal Driver Type

Serial or Ethernet


Connection Information

Connection type: N/A

Baud Rates: N/A

Data Bits: N/A

Stop Bits: N/A

Parity: N/A

Handshaking: N/A

Hardware interface: N/A

Multidrop Capability N/A


Connection Notes

Connection information is not applicable for this driver because only internal data array copies are being made; however, the driver is expecting dummy values to be used for both connection and node information in order to enable the driver.  For all configuration files, use the dummy values provided.


Limitations and Exclusions

  • The driver moves data from the source to the destination by treating the data as a UINT16 or FLOAT.
  • The time-stamp data array should be allocated the same size as the destination data arrays because there always be a corresponding timestamp recorded with any value.
  • The DA_Byte_Name array cannot accept negative values because it is UINT16.
  • The function must be WRBC or WRBX (write on change), it cannot accept RDBC.
  • Scaling is not implemented in this driver.
  • Dummy Connection and Node configuration data described in the Logger driver manual needs to be implemented in order to enable the data logger.
  • On startup, the driver will look for files specified in the “csv’s” and attempt to load the data into the data arrays.   If no such file is found then the driver will create one and start logging data to that file.  If no file storage is desired, then enter “-” into the Filename field.
  • Mixing data file names with the wrong map descriptor will result in driver problems.  Ensure that the correct and unique filename is associated with a single map descriptor.
  • Modifying configurations and not deleting storage files may cause problems.  When changing any configurations, ensure that the corresponding storage file is deleted
If you liked this post;
  • Please consider subscribing to our RSS feed