Momentum Modbus Plus 170 PNT Series Podręcznik Użytkownika Pobierz pdf (Strona 21)

Overview of Momentum M1 Processor Adapters

870USE10110 July 2004 21

Memory and Performance Characteristics of M1 Processor Adapters

Introduction Processor adapters are equipped with internal memory and flash RAM. This section

explains those two types of memory and describes the memory size and

performance characteristics of each processor adapter.

Internal Memory Internal memory includes user memory and state RAM:

User memory contains the control logic program and such system overhead as

the processor adapter configuration, I/O mapping, checksum and system

diagnostics.

State RAM is the area in memory where all the input and output references for

program and control operations are defined and returned.

The user may change the way internal memory is allocated by adjusting parameters

for user memory and state RAM.

Flash RAM Flash RAM contains the executive firmware, which is the operating system for the

PLC. It also contains a firmware kernel, which cannot be changed. The kernel is a

small portion of memory that recognizes acceptable executive firmware packages

and allows them to be downloaded to the processor adapter.

Space is also provided in flash so that a copy of the user program and state RAM

values can be stored. This back-up capability is particularly useful in configurations

where no battery is used (i.e., a processor adapter without an option adapter).

When the module is successfully communicating with other devices, if a ring adapter

with battery back up is not present, it is recommended that you stop the processor

and save the user program to flash. This will save the processor’s ARP cache and

enable it to remember this information if power is lost or removed.

This procedure should also be followed whenever:

a new or substitute device is installed on the network

the IP address of a network device has been changed

Note: Some processors run both IEC and Ladder Logic and some run only IEC.

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Momentum Modbus Plus 170 PNT Series Podręcznik Użytkownika Strona 21