Memory usage examples for data – Echelon LonTal Stack User Manual

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Appendix E: Appendix E

Determining Memory Usage for LonTalk

Stack Applications

Node Data

Bytes Required

Notes:

• Node_SD_length is the length of the self-documentation string for the

node

• NV_SD_length is the length of the self-documentation string for all

network variables (both static and dynamic)

The following table describes the amount of non-volatile memory required for the

application data.

Application Data

Bytes Required

Header 16

Configuration Network Variables

(

)

∑

CPNVlen

File-based CPs

File_length

Application-specific data

Data_length

Notes:

• File-based CPs are configuration properties that are defined in

configuration files

• CPNVlen

is the configuration network variable length of a specific

configuration NV value – the application data includes the sum of the

configuration NV lengths of all configuration NV values

• File_length is the size of the writeable configuration file for the

configuration properties

• Data_length is the length of any addition application-specific data

Memory Usage Examples for Data

The following table shows the approximate amount of RAM that is required for

various example LonTalk Stack applications. Each row of the table represents a

different application by varying the number of network variables, transmit
transactions, receive transactions, aliases, and address table entries. The values

for all columns except the network variable column represent values calculated

by the LonTalk Interface Developer utility.

Note: The listed amounts of memory are based on FTXL device application

requirements. These numbers may vary for LonTalk Stack device applications,
and the may differ based on the host processor and the compliler.
The table assumes that each network variable has a length of 2 bytes, and has a

5-byte self-documentation string associated with it. The table also assumes the
default number of application buffers (5 input buffers, 5 output nonpriority

buffers, and 1 output priority buffer). Varying the number of application buffers