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Tag Addressing |
N1 |
SOETYPE × 10 + Class |
N2 |
Function code. For more information, please check topic Supported Function Codes |
N3 |
Object and variation code. For more information, please check topic Supported Objects |
N4 |
Address of a variable or number |
Device |
Optional parameter informing the logical DNP Address, informed at the parameter "My DNP Addresses". If not informed, the tag will be addressed to the first address of the list (main or default DNP Address). |
Item |
Optional parameter informing a Tag's individual dead band |
The N1 parameter contains a configuration for classes and events, according to the formula SOETYPE × 10 + Class. SOETYPE can be 0 (zero, without SOE), 1 (one, COS or Change of State without timestamp), or 2 (two, SOE or Sequence of Events with timestamp). Class can be 1 (one), 2 (two), or 3 (three). The special cases for the value in the N1 parameter are the following:
•If the N1 parameter is equal to 999, this Tag represent a protocol's On/Off Tag, whose default value is 1 (one). When writing the value 1 (one), it turns off any communication, returning on writing the value 1 (one)
•If the N2 parameter is less than 0 (zero, special functions), the N1 parameter is used to identify a connection, ranging between 1 (one) and 5 (five)
The N3 parameter must be informed according to the formula ObjectCode × 100 + Variation. ObjectCode is a type of object, such as Binary Outputs, and Variation is a sub-type.
The N4 parameter is the address of a variable or number, regardless of being a physical or logical point.
It’s possible to inform an individual dead band per Tag, using the Item parameter in the format DB:X%, where X is a decimal value. For example, the value DB:3% corresponds to 3 (three) percent and the value DB:0,6% corresponds to 0,6 percent.
Alternatively, users can also specify a relative dead band, using at the Item parameter the format DBR:X%, where X is a decimal value. In this way, requests for instantaneous values, such as Class 0 (zero), always report an updated value, while events are only generated if the value is above/below the dead band relative to the last reported event.
It is also possible to specify a special dead band for integer analog tags which represent a bit array (ex: WORD or DWORD with each bit representing a digital state) by defining at the Item parameter the format DB:BSTR. In this case, if there is a change in any bit of this tag an event will be generated, independently from the options "One Analog Event per Index" and "Stop Analog if not Connected" - allowing that changes at this tag will not be lost, independent from the configuration of other analog tags.