GV3000/SE 7V4160 RELIANCE

Reliance GV3000/SE 7V4160 Memory Board, Dynamic

Brand：RELIANCE Model number：GV3000/SE 7V4160

Country of origin: United States Product weight：0.55kg

HS code：9032899099

Product Details：

Product Dimensions：

A Dynamic Memory Board in a Reliance Electric PLC or controller system is a printed circuit board containing DRAM chips, which are used to store the controller's program logic, data tables, and system variables. Dynamic memory requires periodic "refreshing" to retain its data, unlike static RAM (SRAM). These boards were typically plug-in modules that fit into a backplane or chassis of the main controller unit.

Functionality: The primary function of a dynamic memory board is to provide volatile storage for the PLC's operational program and runtime data. This includes:

Program Memory: Storing the ladder logic, function block diagrams, or other control programs.
Data Memory: Holding values for timers, counters, registers, I/O states, and other variables that change during operation.
System Memory: Storing configuration data that needs to be shared between multiple processors in a multi-processor system (often referred to as "Common Memory Modules" in Reliance's AutoMax line, which could use dynamic memory technology).

Architecture: These boards typically consist of multiple DRAM integrated circuits (chips), a memory controller (often part of the main CPU or on the memory board itself) responsible for refreshing the data, and an interface to the system's backplane bus.
Volatile Nature: Being dynamic memory, the data is lost if power is removed, unless backed up by a battery or super-capacitor (a common feature on these industrial modules).

Product Parameters

Specific parameters for Reliance Dynamic Memory Boards would vary by the controller series and the exact module. Common parameters include:

Memory Capacity: The total amount of data the board can store, typically measured in K-bytes (e.g., 64K bytes, 128K bytes, 256K bytes).
Memory Type: Specifically DRAM (Dynamic Random-Access Memory).
Access Time: The speed at which data can be read from or written to the memory (though this was less emphasized for PLCs than for general-purpose computers, as PLC cycle times were the primary performance metric).
Power Requirements: The voltage supplied by the backplane (e.g., 5V DC, 12V DC).
Battery Backup: Often featured an onboard battery or super-capacitor for retaining data during power outages, with specifications for backup duration (e.g., "charges to 90% in approximately 8 minutes").
Physical Interface: Connector type for plugging into the PLC's chassis or rack backplane.
Operating Temperature: Standard industrial operating temperature ranges.

Product Advantages

Cost-Effectiveness (Historically): Dynamic memory was generally more cost-effective per bit compared to static RAM (SRAM) at the time of their widespread use, allowing for higher memory capacities in controllers.
Higher Density (Historically): DRAM allowed for denser memory packaging, meaning more memory could be placed on a single board compared to SRAM for a similar footprint.
Program and Data Storage: Provided essential volatile storage for complex control programs and large datasets in legacy PLC/DCS systems.
Modular Design: As plug-in modules, they allowed for system expansion by adding more memory boards when application requirements grew.
Integrated Backup: The inclusion of battery or super-capacitor backup was a significant advantage for maintaining program integrity during power interruptions without losing critical runtime data.

Important Considerations

Volatile Nature: Despite battery backup, dynamic memory is inherently volatile. Loss of battery power or battery failure would result in program and data loss, necessitating re-downloading the program. Regular battery checks and replacements are critical.
Refresh Requirement: The need for constant refreshing means the memory controller expends resources to maintain data, which can slightly impact overall system performance compared to SRAM, though this impact was generally negligible for typical PLC tasks.
Obsolescence: Reliance Electric dynamic memory boards are now considered legacy or obsolete products. Finding replacements, repair services, and technical documentation can be challenging. Users with these systems often maintain spares or plan for modernization.
Static Electricity: As with all electronic circuit boards, they are sensitive to static electricity. Proper handling procedures (e.g., anti-static bags, grounding straps) are essential during installation or removal.
Module Slot Dependency: In some Reliance systems (e.g., AutoMax), specific memory modules (like "Common Memory Modules") were required in particular slots (e.g., slot 0) for multi-processor configurations or to store shared configuration data. Incorrect placement could lead to system malfunction.

Product Applications

Reliance Dynamic Memory Boards were integral to the functionality of the PLC and DCS systems they served, finding widespread application in:

General Industrial Automation: Storing control programs for automated machinery, assembly lines, and discrete manufacturing processes.
Process Control: Holding parameters and recipe data for continuous and batch processes in industries like chemical, oil and gas, food and beverage, and water treatment.
Material Handling: Storing programs for conveyor systems, robotic cells, and automated storage and retrieval systems.
Building Management Systems: Used in larger industrial or commercial building automation systems to store control logic for HVAC, lighting, and security.
Any application requiring user program and data storage within a PLC/DCS: They were fundamental to enabling the PLC's core function of executing control logic.

0-56940-606 RELIANCE

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