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GE Fanuc Series 90-30 CPUs

CPUs

CPU – Three of the 90-30 PLCs have their CPUs embedded directly into the baseplate of the rack, but the majority of them use plug-in modules. The CPU is the brains of the system. Every PLC must have a CPU to function. The CPU controls the system's software, applications, operations, and monitors all aspects of the system's functions, including operations and faults. Some 90-30 PLC systems have their CPU in a personal computer which interfaces with the system.

To properly configure a system to fit your requirements it is necessary to judge a number of aspects about your intended results. The system will only perform as well as the CPU you ultimately select. Comparing the various capabilities of each CPU is necessary to determine what is best for your application. Here are the major considerations to consider:

  • I/O Points – this is the first step because the conclusions you reach here will determine the component choices you will ultimately select. Knowing the number of modules needed and their physical locations determines the ultimate number of remote or extension racks needed in addition to the primary CPU rack. Start by determining the number of input and output points required to create the system. Correlate with the mechanical drawings and specifications. List all inputs and outputs required, noting the various types required. List them according to Discrete Input, Discrete Output, Analog Input, and Analog Output, noting any special requirements, such as physical separation and the need for remote or expansion racks.
  • I/O Modules – Having determined the number of I/O points required, it is time to select the I/O Modules needed. With over 100 different I/O Modules available, you'll want to consider the following selections factors:
    • Voltage/Current Requirements – the Series 90-30 can meet various common voltage and current needs, such as AC/DC and 110/120V or 240V. These consideration will be used to ultimately determine the power supply selected also.
    • Isolation Requirements – do the racks need to be protected from harsh environments, extreme magnetic forces, temperature or humidity extremes, or the like? How far away will the system components need to be? The use of expansion and remote racks will fulfill these needs.
    • Standardization – Does your company use specific modules or components to simplify training and/or stocking of spare parts?
    • Cost – By selecting certain higher volume modules it is possible to reduce overall system design by one or more racks. As an example, 32 point I/O Modules require much less rack space than lower density modules.
  • Communication and Specialty Modules – System needs will need to be assessed with regard to Ethernet or other communication networks, interfacing with equipment such as CNC machinery, high speed inputs such as counters and motion control, temperature controls, and other needs the system might require.

Having determined the number of modules required for the system, it is now possible to make a CPU selection. There are two basic types of CPUs offered in the GE 90-30 Series: 1. CPUs embedded in the system circuit board, and 2. CPU Modules.

The racks with embedded CPUs in the circuit boards all use the 80188 microprocessor. These CPUs do not have a TOD (time of day) clock. The embedded CPU is a low cost alternative for simpler systems requiring fewer input/output points and less memory to perform the needed functions. Embedded CPU systems are limited to the numbers of slots available in the rack chosen. A system with no more than 10 modules is the maximum attainable with the embedded CPU, since they cannot be used in conjunction with remote or expansion racks.

Modular CPUs come in many different configurations to allow greater versatility. The microprocessor in the Series 90-30 handles all operational control and uses RAM working memory. If the modules required for the system is over ten, the modular CPU system is the only option. If the system is no more than 5 racks CPU331 to CPU341 can be used. For systems up to 8 total racks CPU350 to CPU364 can be used. If a total of 49 or more Communication Modules and I/O Modules are to be used, the system requires CPU350 to CPU374.

When comparing the various CPUs available in the chart below you will note some of the differences which need to be considered in addition to the above. Determining the speed of the processor the system requires will aid in the selection. Also, note the memory capabilities of each CPU. Finally, does your application require the use of floating point math? Although all of the Series 90-30 CPUs are capable of working with whole integers, the floating point math feature of CPU350 and above enables the CPU to deal with decimal numbers as well. These CPUs also enable the use of trigonometric, logarithmic, exponential, and radian conversion factors. CPU352 and CPU374 have built in math co-processor chips, affording the fastest speed for math calculations of all the CPUs. The other CPUs in the CPU350 and above group use firmware enabled floating point math. If ultra-fast performance is not a priority, they are a reasonable, cost effective option.

Other considerations include TOD (time of day) clock requirements. None of the embedded CPUs have a TOD clock, while all of the modular CPUs have one. Also, if keylock capability is required, you will need to choose CPU360 to CPU374, which come equipped with keylocks to prevent all unauthorized access. Although all the CPUs have password protection built-in, only these model have physical locks on the system CPU.

The performance values for the various models of the 90-30 PLC are as follows:

PART NUMBERSPEED
(MHz)
PROCESSORI/O POINTSREGISTER
MEMORY
(BYTES)
USER MEMORY
(MAXIMUM)
(BYTES)
FLOATING
POINT MATH
SYSTEM
IC693CPU31110801881601K6KNO16 BIT
IC693CPU31310801881602K12KNO16 BIT
IC693CPU32310801883202K12KNO16 BIT
IC693CPU33110801885124K16KNO16 BIT
IC696CPU3402080C188XL51219.9K32KNO16 BIT
IC693CPU3412080C188XL51219.9K80KNO16 BIT
IC693CPU3502580386EX204819.9K32KYES32 BIT
IC693CPU3512580386EX2048240K TOTAL240K TOTALYES32 BIT
IC693CPU3522580386EX2048240K TOTAL240K TOTALYES32 BIT
IC693CPU3602580386EX2048240K TOTAL240K TOTALYES32 BIT
IC693CPU3632580386EX2048240K TOTAL240K TOTALYES32 BIT
IC693CPU3642580386EX2048240K TOTAL240K TOTALYES32 BIT
IC693CPU3741335862048240K TOTAL240K TOTALYES32 (64) BIT

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