DNP Slave Import Module
The Distributed Network Protocol Version 3.0 (DNP 3.0) is an open protocol used in the electric utility industry for communications and interoperability among substation computers, RTUs, IEDs, and Master Stations.
An ION device can be integrated into a DNP network through the DNP Slave Import, Export and Options modules. A DNP Slave Import module can map either DNP Analog Output or Binary Output objects to ION numeric and Boolean values. The DNP Slave Import module also enables the device to react to control commands from the DNP Master.
Complete documentation of the DNP protocol is available through the DNP User’s Group (on the web at www.dnp.org). This documentation includes the Application Layer Protocol Description, Data Link Layer Protocol Description, Transport Functions, Data Object Library, and DNP 3.0 Subset Definitions.
The DNP Slave Import module does not have any inputs.
The setup registers and their options are listed below. If the combination of options you choose is invalid, the module will not assume operation, and an error message will appear in the configuration software. These setup registers allow you to define a DNP object. In DNP, objects are defined by a point and a group.
This register specifies the point number of the DNP object to which you want to map the module. Note that DNP does not allow any overlaps in the DNP point numbers within a DNP group (Binary Output or Analog Output). If you have already configured other DNP Slave Import modules, you must refer to the previous module’s DNPPoint setup register to extrapolate the appropriate point number for this new module. If this is your first DNP Slave Import module, use zero for the point number.
This specifies the group of the DNP object to which you want to map the module. Refer to your device documentation for setup register defaults and choices.
This specifies the method of accessing trip/close relays. This setup register only applies to Binary Output objects. Refer to your device documentation for setup register defaults and choices.
This register provides the ION numeric equivalent to the DNP object received from the Master. DNP Analog Output objects are converted to a numeric value. If the DNPObjGrp setup register is set to binary output, this output register will be n/a.
This register goes on or off when the module receives an Operate or Direct Operate function from the DNP Master according to the table in the Control Relay Block Implementation section that follows.
If the DNPObjGrp setup register is set to analog output, this output register will be n/a. This output register can be used for controlling latching or trip/close relays.
This register goes on or off when the module receives an Operate or Direct Operate function from the DNP Master according to the table in the Control Relay Block Implementation section that follows. If theDNPObjGrp setup register is set to analog output or Relay Mode is set to 1 point per address this output register will be n/a.
This output register is only used for closing a trip/close relay when 2 points per address are used.
ION events are recorded in this output register. Possible ION events include changes to setup registers or labels (both which have a priority of 10).
The Event output register stores the following information for each ION event: timestamp, event priority, event’s cause, event’s effect, and conditions associated with the event’s cause and effect.
Responses to special conditions
The following table summarizes how the DNP Slave Import module behaves under different conditions.
|Condition||Response of Output Registers|
|Module is first created||All output register are n/a.|
|If the setup registers are changed (i.e. the module is mapped to a different DNP object)||If DNPObjGrp is analog output, the AnalogOut output register is set to 0 and is updated on
receipt of the next Master request to this point.
If DNPObjGrp is binary output, the Relay output registers go off and are updated on receipt of the next Master request to this point.
|On device power up||Output registers will remain at the last updated value.|
Detailed module operation
The following tables summarizes all the functions that the DNP Master can perform when it writes to the DNP Slave Import module.
DNP Master Transfer Functions
|Confirm||Message fragment confirmation used in Master requests. No response to this message is required.|
|Read||Master requests particular objects from IED; IED responds with requested objects that are available. For Analog Outputs, the value of the AnalogOut output register is returned as the status. For Binary Outputs, the OR’d value of the Relay1 & Relay2 output registers are returned as the status. For Class 0 polls, status of all Analog and Binary Outputs are returned.|
DNP Master Control Functions
|Select||Select (or arm) output points (controls, setpoints, analog outputs) at IED but do not activate them; IED responds with the status of the output points selected. When it receives the select message, the IED starts a timer and must receive an operate message before the timer expires to activate these outputs.|
|Operate||Activate the IED’s outputs that were previously selected with the select function; respond with the status of the outputs.|
|Direct Operate||Activate the IED’s outputs without a preceding select message; IED responds with the status of the outputs.|
|Direct Operate - No Acknowledge||Activate the IED’s outputs without a preceding select message; but IED does not respond with the status of the outputs.|
Control Relay Block Implementation
This implementation follows the recommendations of the DNP Users Group document Control Relay Output Block Explanation and Recommended Usage (August 30, 1995).
|Function Desired||Fields of Control Relay Output Block Object||Setup Register||Behaviour of Output Registers|
|Code (Bits 0-3)||Trip/Close (Bits 6&7)||On-time||Relay Mode||Relay 1||Relay 2|
|Latching Relay ON||Latch On (3)||NULL (0)||ignored||ignored||ON||No change|
|Latching Relay OFF||Latch Off (4)||NULL (0)||ignored||ignored||OFF||No change|
|Unpaired Momentary Relay (e.g Pushbutton, Alarm)||Pulse On (1)||NULL (0)||X ms||ignored||ON (for X ms)||No change|
|Trip Breaker/Relay, Raise Transformer Tap||Pulse On (1)||Trip (2)||X ms||ignored||ON (for X ms)||No change|
|Close Breaker/Relay, Lower Transformer Tap||Pulse On (1)||Close (1)||X ms||1 point per address||ON (for X ms)||No change|
|Close Breaker/Relay, Lower Transformer Tap||Pulse On (1)||Close (1)||X ms||2 points per address||No change||No change|