Dnp3 - Fields - Applied Systems Engineering ASE2000 User Manual

26.1.1. DNP3 – Fields
Name is used to identify the exchange on the Line Monitoring and Messages views. This field is
normally not modified since default names reflect exchange functionality. The name is not used
by ASE2000 internal processing.
Frequency defines how often a message is to be transmitted (in seconds). It is applicable in
Master Simulation Mode when communication is started with the Send Continuous or Start
button. In RTU Simulation Mode, it is used for unsolicited data reporting. It is not applicable in
Line Monitoring Mode.
When Send Continuous is selected, the selected exchange message is sent immediately and,
thereafter, at regular intervals specified by the Frequency.
When Start is selected in Master Simulation mode, each exchange with its Transmit flag
set is transmitted at the associated frequency. The first transmission occurs at the frequency
interval after Start, with subsequent transmissions periodically thereafter. For example, if two
exchanges both have the Transmit flag set, one with a frequency of 2.0 seconds and another
with 3.0 seconds, the first exchange is sent 2 seconds after Start is pressed and every 2 seconds
thereafter. The second exchange is sent 3 seconds after Start is pressed and every 3 seconds
thereafter.
A special frequency value of 0 seconds (along with setting the Transmit flag) causes the
exchange to be sent once immediately after Start is pressed.
Note that frequency settings define the desired transmission rate. An exchange is never sent
before processing of the prior exchange has terminated, either because the entire response has
not yet been received or because no response has been received and the response timeout
period has not yet expired.
For RTU Simulation, frequency defines how often an "unsolicited data reporting" message is
transmitted. Frequency is not used if not operating in unsolicited data reporting mode.
Display and Event flags are as defined in the main ASE200 document. There is no special
meaning for DNP protocols.
Transmit flag causes a message to be transmitted according to rules discussed for the frequency
setting, above.
Data Link Layer Function is used to select the function code to transmit. Except for one case,
this field is informational and should not be altered. The one case where it can be changed is to
switch between User Data (No Confirm) and User Data (Confirm). If the default function code
is either of these, it can be safely modified to the other. The setting (Confirm or Not) is not used
for processing incoming messages.
Data Link Layer PRM and FCV checkboxes define whether or not the PRM and FCV bits
should be set in the function code byte. The ASE2000 always sets these fields correctly based
on the Data Link function code. If modified, an incorrectly formatted message will be sent. The
checkboxes are included in this menu only for that purpose, that is, to transmit an incorrectly
formatted message to verify error handling by another DNP3 device.
Dest and Source define the exchange's Destination and Source addresses. Either an '*' or
specific value can be entered. An '*' instructs the ASE2000 to use the system default (see
ASE2000 V2 Communication Test Set User Manual 151