RX3i Processor Selection Guide

The RX3i Processor is considered to be the brain of Programmable Automation Controllers (PAC); which consist of a Power Supply, Processor, and the Input/Output section. Programmable Automation Controllers are compact control systems used in control, machine control, logic control, motion control, and other general-purpose control applications in an industrial setup. Their functionality is similar to Programmable Logic Controllers (PLCs), but they are equipped with advanced software features like in Personal Computers (PCs). Hence, the RX3i Processor is used in PAC systems that require advanced signal processing, data logging, and other capabilities to automate the control of single or multiple pieces of equipment.

The RX3i Processor can communicate with HMI devices and the programmer through a serial port using Series Ninety Protocol (SNP) Slave protocol. It also communicates with smart option modules and Input/Output devices over a dual backplane bus. This dual backplane bus consists of a high-speed Peripheral Component Interconnect (PCI) backplane for fast integration of new/advanced Input/Output; and a serial backplane which makes it easy to migrate existing Series 90-30 Input/ Output. The RX3i processor supports user-defined Structured Text and Function Blocks (LD logic only) programming. Most of the RX3i processors currently available in the market are part of GE Intelligent Platform and Emmerson Automation solutions. This article focuses on the selection criteria for GE R3Xi Processor.

RX3i Processor Hardware 

The RX3i hardware system consists of an RX3i Universal Backplane (Baseplate) and at most seven expansion/ remote racks for Series 90-30. Any slot on the RX3i Universal backplane can be used to install the RX3i CPU besides the last slot, which is set aside for the serial bus transmitter with a catalog prefix IC695LRE001.

A) RX3i Universal Backplane  

The RX3i processor system you select must include at least one Universal Backplane, which accommodates the RX3i CPU. RX3i Universal Backplanes are available in three sizes namely: 16-slot (IC695CHS016), 12-slot (IC695CHS012), and 7-slot (IC695CHS007). With its dual-purpose capability, this RX3i Universal backplane supports both high-speed PCI-based backplane (IC695) as well as most RX3i analog and discrete Input/Output with catalog prefixes IC694 and IC693, and other optional modules. In particular, it supports Series 90-30 Motion Control and Genius Bus Controller modules.

Also, the RX3i Universal backplanes can reduce downtime as they support hot swaps and advanced diagnostic capabilities. It is important to note that RX3i modules whose catalog prefixes are IC95, can only be installed in the universal backplane including the Ethernet and other communications modules.

B) RX3i Expansion Systems 

In case your application requires more RX3i modules than your chosen Universal Baseplate can accommodate, or when some of these modules will be remotely located, you can use a combination of at most seven Expansion and/or Remote series 90-30 Backplanes. Remote Backplanes provide similar functionality as the Expansion Backplanes but over a much larger distance.

To connect the Expansion/ Remote backplanes to your RX3i system, you must first install an RX3i Serial Bus Transmitter Module (with a catalog number IC695LRE001) in the last slot of your RX3i Universal Backplane. Note, only 16-slot and 12-slot Universal Backplanes can accommodate the LRE001 Bus Transmitter. Afterward, you can connect the first Expansion or Remote Backplane to the LRE001 Bus Transmitter, via a cable. You should use a D-connector to connect the RX3i Serial Expansion/ Remote backplanes to the LRE001 Transmitter. Subsequent serial racks are then daisy-chained together using cables.

If your RX3i system consists of only one Expansion system, the total distance between the RX3i CPU to the last backplane should not be more than 50 feet (15 meters), as illustrated below:

However, if you need several Expansion or Remote Backplanes, ensure that the overall distance from the RX3i CPU to the last backplane is not more than 700 feet (213 meters). Also, ensure that the Remote backplanes you select for your RX3i system have an extra isolation circuitry to lessen the effect of unbalanced ground conditions which can occur when backplanes do not have a common ground system or are located at longer distances from each other. In addition, communications between the RX3i CPU and a Remote Backplane are likely to take a slightly longer period compared to communications between the RX3i CPU and a serial Expansion Backplane, so don’t panic when that happens. Though this delay is normally small compared to the overall CPU scan time.

RX3i Backplanes  

The table below lists several Universal, Expansion, and Remote Backplanes that are compatible with an RX3i Processor.

The RX3i CPU Models 

The RX3i CPUs are based on the latest processor technology characterized by high-performance, fast computation, and high throughput. These powerful CPUs are well-suited for complex applications which they can easily compute and solve using the high-performance RX3i processors and with up to 64MBs of user memory. The RX3i processor will also give you program flexibility as it supports multiple aforementioned IEC languages in addition to C programming.

Also, the RX3i processor supports Hot Standby (HSB) CPU redundancy, this feature allows critical processes or applications to continue operating whenever any component fails. A typical CPU redundancy system includes an active unit that actively regulates the process being controlled and a backup unit that is always synchronized with the active unit. Hence, the backup unit can take over whenever the active unit fails or when it becomes necessary to do so. Therefore, ensure that each of your RX3i units has a redundancy CPU.

In addition, an RX3i system can have a backplane-based CPU redundancy. In such a case, Redundancy Memory Xchange (RMX) modules (with a catalog No. IC695RMX128) provide the redundancy CPU communication path. The RMX modules are set up as redundancy links. Ethernet-based RX3i redundancy CPUs are also available, whereby Ethernet connections between the redundant RX3i CPUs provide the redundancy communication path.

The table below provides a list of RX3i CPU Models provided by GE, including redundancy CPUs that are supported by the RX3i Processor.

RX3i Communication Features

RX3i Processor supports several open communication modules which include: Ethernet, Serial Protocols, Ethernet Global Data (EGD), PROFIBUS, Modbus TCP, PROFINET, and DNP3. Ethernet communications can be handled by the Ethernet port(s) found in an RX3i CPU with an embedded Ethernet Interface or by an IC695ETM001 module that is installed in an RX3i Universal backplane rack. Serial communications can be handled by the embedded RX3i CPU Serial port(s) or by an IC695CMM004 or IC695CMM002 module installed in an RX3i Universal backplane rack.

A) RX3i Embedded Ethernet Interfaces 

RX3i CPE302, CPE305, CPE310, CPE330, CPE400, and CPL410 CPUs provide one or more embedded Ethernet interfaces used to connect to the PAC Machine Edition (PME) or the programmer. When used, each of these Ethernet interfaces connects to a Local Area Network. You should ensure that each interface on the LAN has a unique IP Address and a non-overlapping, PME configured IP subnet. Therefore, take great to survey and tabulate the already existing IP subnets and IP addresses on the RX3i processor network architecture; to avoid assigning conflicting IP Addresses or configuring duplicate IP subnets.

Once the Ethernet interfaces are connected, the corresponding RJ45 Ethernet port(s) automatically detects the data rate on the linked LAN (10Mbps, 100Mbps, or 1Gbps), as well as the corresponding cabling arrangement (crossover or straight-through), and the corresponding communication mode (full-duplex or half-duplex). This automatic detection of the aforementioned properties will greatly simplify the installation procedures for the RX3i CPU you select.

Some of the important Internet Protocols supported by all RX3i CPUs include:

• TCP/IP protocol: This provides basic Internet connectivity capabilities. For example, the CPE embedded Ethernet port effective with CPE330 firmware version 8.45 or CPE305/CPE310 firmware version 8.20 supports OPC UA Server. All firmware versions of CPL410 and CPE400 have TCP/IP features. 
• Service Request Transfer Protocol (SRTP): This protocol is proprietary and provides an interface between the configuration software and PME programming. It also supports communications with certain supervisory computer layers and control systems on the factory floor. 
• Modbus/TCP: Provides Modbus messaging structure over the Internet. 

The embedded Ethernet port on RX3i CPE330 firmware version 8.50, or CPE310/CPE305 firmware version 7.30 supports Modbus/TCP and SRTP channels. The Modbus/TCP and SRTP feature is also available on all CPL410 and CPE400 versions.

Note that, on the CPE310/CPE305/CPE302 RX3i CPU models, the same shared RX3i processor performs both Controller logic processing and Ethernet port processing. But due to the great hardware advances in the CPL410, CPE400, and CPE330, a higher level of RX3i processing power is required in support of each LAN. This is particularly essential at higher data rates. It also offloads the core processor the task of handling Ethernet-level activity, allowing it to perform just CPU logic and Input/Output scanning more efficiently.

For instance, the dual-core RX3i CPU on CPE330 allows one core to handle I/O scanning and CPU logic while the second core handles communication. Moreover, a dedicated Network Interface Controller (NIC) controls each LAN interface. Also, CPE400 and CPL40 have four microprocessor cores in which one of the four is set aside to handle the communications functions (such as LAN1, LAN2, and LAN3). On CPL410, Linux Operating System controls the Serial Port and Ethernet port on the underside and one of its USB ports; while an RX3i PLC controls all the front-panel ports, except one USB port. And in CPE400, a Field Agent port is dedicated from one of its embedded Ethernet ports.

B) RX3i Serial Communications 

All RX3i CPU models are other than CPE330, support one or several serial ports. You can access the independent serial ports onboard the RX3i CPUs through external connectors located on the module. Serial interfaces to external I/O devices are provided by COM1 and COM2. Also, you can use COM1 for firmware upgrades. You can configure your RX3i COM1 and COM2 serial port modules for one of the following modes:

• Serial I/O: Used for general-purpose serial communications by use of COMMREQ (Communication Request) functions 
• RTU (Remote Terminal Unit) Slave: The Modbus RTU slave protocol can use this port. Also, this mode enables an SNP Master connection to the port, like the RX3i programming software or the WinLoader utility.
• SNP Slave: Can only be used for the SNP (Series Ninety Protocol) slave protocol. 
• Message Mode: This port can be accessed by user logic. It enables C programming language blocks to carry out serial port I/O operations, through C Runtime Library functions. 
• Available: You cannot use this port for RX3i CPUs firmware.

CPU315, CPU310, CPU30, NIU001, CPE310, and CRU320 provide two serial ports, one is RS-485 and the other one is RS-232. Whereas each CPE305, CPE302, CPL410, and CPE400 with firmware version 9.40 provides a single serial port for RS-232. However, CPE330 does not provide any serial port. You can use various communication modules that are compatible with RX3i such as IC695CMM002 and IC695CMM004, to expand the capabilities of your RX3i serial communications system.

C) RX3i Ethernet Global Data 

Ethernet Global Data (EGD) pages are available on RX3i CPUs with firmware versions 8.303, and CPE305/CPE310 RX3i CPUs also support EGD Class 1. Before the development of the aforementioned firmware versions, EGD pages were only available to the RX3i Processor via the RX3i Ethernet Interface module (ETM001). EGD Class 1 is also supported by RX3i firmware version 8.604 and CPE330. This feature is available on all RX3i firmware versions of CPE302, CPE400, and CPL410.

The above-mentioned RX3i CPU models support at most 255 simultaneous EGD pages overall Ethernet interfaces in the controller. Before these EGD pages are stored into the CPU, they should first be configured in the programming software. But you can also load the EGD configuration tools from the programming software into the RX3i CPU. Also, you can configure both consumed and produced pages.

D) RX3i PROFIBUS Communications 

PROFIBUS communications in an RX3i CPU are possible through the PROFIBUS Master module, with a catalog number IC695PBM300. This module allows the RX3i CPU to receive and send data over a PROFIBUS-DB network.

PROFIBUS IC695PBM300 module supports all standard data rates, a maximum of 3,584bytes of output data and similarly 3,584 bytes of input data. It can support up to 125 PROFIBUS-DP slaves, with a maximum of 244 bytes of output data and 244 input data for each slave. It supports Freeze and Sync modes, as well DP-V1 Alarm, Read and Write messages. IC695PBM300 module also has network status LEDs and PROFIBUS-compliant module.

Note that, the PROFIBUS IC695PBM300 module is only compatible with an RX3i CPU that has a firmware version 2.9 or more advanced. Also, this module can only be installed in an RX3i Universal Backplane. And it indirectly receives its firmware upgrades through the WinLoader software utility from the host controller CPU. So, whenever you purchase an update of the PROFIBUS Master module software for RX3i, be sure to ask for the WinLoader utility software.

E) RX3i PROFINET Communications 

All PROFINET Communications on an RX3i PROFINET network must use RX3i supported PROFINET Controllers and PROFINET I/O devices like a PROFINET Scanner.
RX3i CPU Models IC695CPE330 and IC695CPE400 support embedded PROFINET Controller functions. Also, the RX3i Processor supports a rack-mounted PROFINET Controller module whose catalog number is IC695PNC001.
Additionally, supported PROFINET Scanners are the VersaMax PROFINET Scanners IC200PNS002 and IC200PNS001, as well as RX3i PROFINET Scanner modules IC695PNS101, IC695PNS0017, and the RX3i IC695CEP001.

Note, a connection or rather an Application Relationship must first be established between an RX3i PROFINET Controller and PROFINET I/O Device before the two devices can communicate or exchange data. Hence, RX3i PROFINET I/O-Controller is more often considered for most industrial control applications; as it automatically sets up the correct type and number of Communication Relationship and Application Relationship channels depending on its PME configuration. Normally, you can only establish one Application Relationship per I/O Device.

F) RX3i HART Pass Through 

HART (Highway Addressable Remote Transducer) enables an RX3i CPU to exchange HART asset management data between PC-based asset management tools and HART-capable I/O modules. Thus, for HART Pass-Through operation to be possible one requires RX3i Analog modules and PC-based applications with HART functionality, and optional supporting PROFINET products.

The RX3i CPUs that are compatible with HART Pass-Through include IC695CPU320, IC695CPU315, IC695CRU320, IC695CPE330 with firmware version 8.50 or higher. All firmware versions of IC695CPE302 support the HART feature.

The RX3i analog modules which support HART include: IC695ALG72, IC695ALG728, IC695ALG628, and IC695ALG626.

If you consider using the HART Pass-Through with supporting RX3i PROFINET Scanner and RX3i PROFINET Controller, make sure that the two devices contain HART-compatible firmware such as:

• AK firmware version 2.20 for RX3i IC695PNC001 PROFINET Controller  
• ABAH firmware version 2.3010 for RX3i IC695PNS001 PROFINET Scanner 
• AAAA firmware version 3.10 for RX3i IC695PNS101 PROFINET Scanner
• AAAD firmware version 2.30 for RX3i IC695CEP001 PROFINET I/O Device 

Overall, an RX3i Processor increases machine cycle times, and its extensive hot-swap and diagnostics capabilities reduce downtime. And its large user memory capacity allows you to store huge amounts of data enabling you to significantly reduce your expenditure on external hardware.

This article provides you with comprehensive guidelines for selecting the Hardware, CPU models, and Communication modules for a GE-produced RX3i Processor. We have extensively reviewed the RX3i hardware components including the available RX3i Universal, Expansion, and Remote Backplanes. Also, we have provided a list of almost all RX3i CPU models and their descriptions. And a comprehensive outline of the various RX3i supported communication modules such as Embedded Ethernet Interfaces, Serial Communications, Ethernet Global Data (EGD), PROFIBUS, PROFINET, and HART Pass-Through.

We hope that this overview of RX3i Processors has been helpful in understanding your selection options.  For more information or to discuss which equipment might be best for your application, please visit our website here, or contact us at [email protected] or 1-919-535-3180. 

This entry was posted on September 15th, 2021 and is filed under Uncategorized. Both comments and pings are currently closed.