The Local Data Logging (LDL or Local Printer) serial port is used by the RTU for delivering selected categories of information to a locally connected logging terminal. Such terminals may be printers or computers using serial interfaces.
When made active by configuring Local Printer as a Device, the LDL function will automatically print a description of each event that occurs (within the categories of information selected in the configuration process).
Items to Print Include:
RTU Events
· Configuration Changes – all programming changes are sent to the printer
· Session History – all session messages are sent to the printer
· Data Sampling – Snapshots of data taken at intervals specified by the user
Channel Events
· Alarms – all alarm messages are sent to the printer
· Alarm Acknowledged – whenever alarms are acknowledged, the acknowledgment message is delivered to the printer
· Reset – when acknowledged alarms reset to normal, a message is sent to the printer.
A time and date stamp will be included with each report. If PINs are configured, the operator PIN Name (not the PIN itself) will be attached to the information being logged. The information is delivered in flat ASCII format.
For an example of a typical LDL printer output, see Local Data Logger Printer Output Examples.