NVRAM

KAS uses (missing or bad snippet) to save Retain Variables.

Hardware Type

NVRAMClosed "Non-volatile random access memory" NVRAM is the general name used to describe any type of random access memory which does not lose its information when power is turned off. This is in contrast to the most common forms of random access memory today, which both require continual power in order to maintain their data. NVRAM is a subgroup of the more general class of non-volatile memory types, the difference being that NVRAM devices offer random access, like hard disks. The best-known form of NVRAM memory today is flash memory Size Allocation

Simulator

256 Kbytes

AKD PDMM or PCMM

32 Kbytes

PCMM2G

256 Kbytes

  • Part of (missing or bad snippet) allocation is reserved to store some internal data (144 bytes).
    As a consequence, not all of the complete physical (missing or bad snippet) is available for the retain variables.

If the size is big enough, KAS updates the non-volatile memory to store the retain variables values.

  • This operation is performed in the background every 20 seconds.
  • The frequency increases to every two seconds when the application is running or when you shutdown the application.

(missing or bad snippet) Life Expectancy

  • Data Retention: At maximum operating temperature, the data written to the memory is retained for 10 years.
  • Endurance: (missing or bad snippet) memory has an endurance limit of 1014 read/write accesses.
    • More than 6,000,000 years of being accessed every 2 seconds.

  • Using the retain variables is very cycle time consuming.
    As a consequence, Kollmorgen strongly recommends to carefully monitor the system load with the TraceTimes command.

Verify the (missing or bad snippet) Space

To calculate (missing or bad snippet) space, add the size of each retained variable according to the:

  • Data Types
  • Arrays - The numbers of elements in case the variable is declared as an array.

Remember! Add the 144 bytes!

In this example, the total size is: 3684 bits (which is less than 0.5 Kbytes).

Variable

Size / element

Number of Element

Total Size / variable

bLedStatus

1-bit

4

4

Internal data

1152-bits (144 bytes)

N/A

1152

MasterAbsPos

64-bits

1

64

MyString

800-bits (100 bytes)

3

2400

TravelSpeed

64-bits

1

64