A-B Ethernet Communications

ORMEC’s MotionBASIC Extension (MBX) for Allen-Bradley Ethernet communications adds to the network capability of the ORION controller. A-B Ethernet provides a fast, low cost method to send and receive application data between controllers on an Ethernet network using A-B Ethernet communications. The MBX adds MotionBASIC statements making it simple to use Ethernet to communicate between ORION controllers, Allen-Bradley PLCs and PCs running popular HMI packages.

Features and Benefits

Key advantages of  A-B Ethernet MBX communications:

• Interfaces an ORION controller directly to SLC-5/05 PLCs and PLC5 family PLCs that support Ethernet.
• Connects an ORION controller to popular HMI packages that use A-B Ethernet to transfer integers and floating point variables as object tags for operator input and output.
• Using standard Ethernet cards provides a low cost physical interface to the ORION controller.
• Based on standard Internet technologies, TCP/IP protocol is layered on high speed 10base Ethernet networks.
• Enhances the flexibility and performance of message transfers by allowing peer-to-peer connections between network nodes.

Overview

The A-B Ethernet MBX extends the MotionBASIC operating system to provide connectivity between ORION controllers, Allen-Bradley PLCs and PCs running popular HMI packages by using A-B Ethernet communications. An ORION controller with an Ethernet link installed and configured with the A-B Ethernet MBX, can open an A-B connection to send application data to any A-B server node on the network. The ORION controller also has the ability to start a server node that will accept any connection from another A-B node and receive application data.

Multi-protocol capability

Software development for a system with multiple ORION controllers using the full capabilities of A-B communications can be performed with one PC. Since Ethernet is a multi-protocol network, any PC connected to the network can establish a TCP/IP connection, communicate to an ORION and run the MotionDesk for program development over the same wire at basically the same time as A-B communications.

A-B Ethernet Architecture

ORION A-B Ethernet consists of a physical layer based on 10baseT, 10base2, or 10base5 type Ethernet communication standards along with a client/server transport protocol (TCP/IP stack) to provide reliable peer-to-peer communications in the ORION controller. At the application level, the MBX-ABE uses a protocol developed for PLC networking to transfer register data as messages between controllers. All transfers happen as background tasks concurrent with the user’s main application program.

User access at the application programming interface level consists of MotionBASIC extensions for making the connection to the destination server and the specifying source and destination registers for a read or a write of  multiple register transfers to that connected server. Concurrent multiple connections can be made to multiple servers on the network for a flexible and efficient arrangement for updating application data between a variety of system components.

For constructing messages,  MotionBASIC mapping methods (MBX-MAP) are included to simplify data organization at the PLC register level for the user.

MotionBASIC Variable Mapping

MBX-MAP extends the capability of MotionBASIC by providing a method to map PLC register values to any MotionBASIC variable in the controller. Typically, PLC registers are addressed numerically but MotionBASIC uses symbolic labels to address variables. With mapping, the MotionBASIC variable’s symbolic label can be simultaneously defined as a PLC register address value. Register mapping values can range from 0 to 32367. The main purpose of this mapping feature is to allow the MBX to quickly assemble the content of various variables such as integers, and floats that reside in different areas of the controller’s memory, into an ordered list of data and transferred over the network as one message.

MBX-MAP provides the ability to monitor the changes in selected variables. Any change in the data contained in the variable selected, can result in an event interrupt. The event interrupt, if enabled, will execute a user defined subroutine designed to respond to the changes in the data as a result of receiving the message.

A partial list of PLCs, popular Human Machine Interface (HMI) packages and OCX software controls that can communicate with an ORION controller incorporating the A-B Ethernet MBX:

• PLCs: Allen-Bradley SLC-5/05 and PLC5s that support Ethernet communications
• HMI Packages: RsView32 by Rockwell Automation, InTouch by Wonderware, Fix by Intellution, FactoryLink by U.S. Data and Citect by CI Technologies
• OCX Software Controls: ASABETHERNET an OCX by Automation Solutions, ABEther an OCX by Parijat, Inc., IN-GEAR 32 an OCX by CimQuest, Inc.

Modbus TCP Communications

ORMEC’s MotionBASIC Extensions for Modbus TCP Communications adds to the network capability of the ORION motion controller. Modbus TCP is an provides a fast and low cost method to send and receive application data to any other controller on an Ethernet network installed as a Quantum communication node. The MBX also adds a full list of MotionBASIC statements to configure, control and monitor Quantum PLC activity.

Features and Benefits

Key advantages to using Modbus TCP communications:

• A low cost physical interface to the ORION controller, using standard Ethernet cards.
• Based on standard internet technologies,  TCP/IP protocol layered on a high speed 10base Ethernet network.
• Enhances the flexibility and performance of message transfers by allowing peer-to-peer connections between network nodes.
• Provides reliable connectivity to popular HMI packages that use Modbus TCP to transfer of integers, floating point and text string variables as object tags for operator input and output.
• Based on open standards for effective integration to other third party components.

Overview

Modbus TCP communications extends the MotionBASIC operating system to provide high speed connectivity between multiple ORION controllers as well as to third party PLCs and HMI packages that communicate with the Modbus TCP protocol over an Ethernet network. An ORION controller, with an Ethernet link installed and configured with the MBX software extensions, can open a Modbus TCP connection to send application data to any Modbus TCP server node on the network. The ORION also has the ability to start a server node that will accept any connection from another Modbus TCP node and receive application data.

Multi-protocol capability

Software development for a system with multiple ORION controllers using the full capabilities of Modbus TCP communications can now be performed with one PC. Since Ethernet is a multi-protocol network, any PC connected to the network can establish a TCP/IP connection, communicate to an ORION and run the MotionDesk for program development over the same wire at basically the same time Modbus TCP communications are also going on.

Modbus TCP Architecture

ORION Modbus TCP consists of a physical layer based on 10baseT, 10base2, or 10base5 type Ethernet communication standards along with a client/server transport protocol (TCP/IP stack) to provide reliable peer-to-peer communications in the ORION controller. At the application level, the MBX uses the Modbus protocol developed for the PLC industry to transfer register data as messages between controllers. All transfers happen as a background task concurrent with the user’s main application program.

User access at the application programming interface level consists of MotionBASIC extensions for making the connection to the destination server and the specifying source and destination registers for a read or a write multiple register transfer to that connected server. Concurrent multiple connections can be made to multiple servers on the network for a flexible and efficient arrangement for updating application data between a variety of system components.

For constructing messages, the MBX provides MotionBASIC mapping capabilities to simplify data organization at the PLC register level for the user.

MotionBASIC Variable Mapping

The ability to map variables provides a way to map PLC register values to any MotionBASIC variable in the controller. Typically, PLC registers are addressed numerically, but MotionBASIC uses symbolic labels to address its variables.

With mapping, the symbolic label of the MotionBASIC variable can be simultaneously defined as a PLC register address value. Register mapping values can range from 0 to 32367. The main purpose of this mapping feature is to allow the MBX to quickly assemble the content of various variables such as integers, floats and strings that reside in different areas of the controller’s memory, into an ordered list of data and transferred over the network as one message.

The MBX also provides the ability to monitor the changes in selected variables. Any change in the data contained in the variable selected, can result in an event interrupt. The event interrupt, if enabled, will in turn execute a user defined block of code (subroutine) designed to respond to the changes in the data as a result of receiving the message.

Profibus DP Communications

ORMEC provides Profibus connectivity to the ORION motion controllers by using a standard Profibus communications adapter and a MotionBASIC Extension (MBX) to implement either Profibus DP Master or Slave communications. Connectivity to the ORION controller provides the machine developer with a modern approach to machine control networking using Profibus DP communications.

Features and Benefits

Key advantages of using Profibus DP communications:

• Factory connectivity: Profibus DP provides a convenient way to integrate ORION with PLCs or PCs running HMI or soft PLC programs and using the open Profibus DP network for distributed I/O.
• High-speed, cost-effective: A standard Profibus adapter provides performance up to 12 Mbits/sec using a master-slave protocol with up to 126 nodes.|
• Minimal impact on MotionBASIC program execution speed: Once initialized, Profibus communications between the Master and Slave(s) takes place as a background task controlled by a processor on the Profibus Adapter, minimizing application program complexity and workload on the ORION controller.

Overview

Profibus is a vendor-independent, open fieldbus standard for a wide range of applications in manufacturing. Vendor independence and openness are guaranteed by the Profibus standard EN 50170. With Profibus, a developer provides uniformity between devices of different manufacturers by using a fast and efficient communications protocol. Profibus can be used for both high-speed time critical data transmission and extensive complex communication tasks without interface modifications. High-speed, time-critical data transmission at the fieldbus level is defined by the Profibus DP specification.

Profibus DP Bus Interface

The combination of a Profibus Communications Adapter and Profibus MBXs gives Profibus DP Master or Slave functionality to an ORION motion controller. Slaves on a Profibus DP bus appear as I/O drops with up to 244 bytes of inputs and 244 bytes of outputs each. The inputs and outputs can be divided between bit data and 16-bit word data. The word data is used to pass system parameter and status information between the Slave and a Profibus DP Master.

Profibus DP Architecture

Profibus DP defines the technical and functional characteristics of a serial Fieldbus which interconnects distributed digital field devices in the low (sensor/ actuator level) up to the medium (cell level) performance range. The basic system architecture consists of one or more master devices and one or more slave devices. Any master device can control the bus. When it has the right to access the bus, a master will transfer messages without waiting for a remote request. Slave devices are peripheral devices that have no bus access rights - i.e. they may only acknowledge received messages or, at the request of a master, transmit messages.

Profibus DP Configuration

A network configuration program and device configuration file (*.GSD) are supplied with the Profibus adapter. The device configuration file is used by the network configuration program to create the configuration data file that is read by the DP Master. The device configuration file tells the network configuration program what the capabilities of the node are and whether the user can choose how much data to transfer. In the case of a simple solenoid bank or proximity sensor, the amount of data available from the node is predetermined and fixed. In the case of a configurable node the user can program the amount of data the node is able to exchange.

In either case, each slave device needs a configuration data file to use at initialization time to know how the node will present its data on the network and how many inputs and outputs each node will have. The Profibus Communications adapter used with ORION as a DP Slave provides this type of configurable node. Network configuration file (netslv.ncf) and a slave configuration file (slave.scf), modified by the user, tell the Profibus DP Slave MBX driver how to split up 244 bytes of input data and 244 bytes of output data between bits and words, how many bytes of inputs and outputs are being transferred, its node address and the baud rate of the card. The PFB.DUMP commands and PFBLOG.TXT file verify installation.

The Profibus Communications adapter used with an ORION as a DP Master uses the configuration data file to initialize all the configurable nodes on the network at startup. The configuration data file also tells the Profibus DP Master MBX how much of each data type to read from each DP Slave node.

Hardware Interface

The Profibus communications MBX uses the adapter installed in the ORION’s ISA bus backplane. Two LEDs on the card provide system status and bus network status indications. The bus interface is a 9-pin D-sub connector. A Siemens 6GK1500-0FC00 (or equivalent) is included with the Profibus Adapter. No special tools or soldering is required to attach the Profibus Cable to the Siemens 9-pin connector.

Physical Layer

The recommended cable is Belden Profibus Cable 3079A. A Profibus network must be terminated at devices located at each end. Siemens 9-pin cable connectors have switches in their shell to turn the terminator on and off. The default bus transfer rate is set at 12M bps. Scan rates are dependent on the total number of inputs and outputs on all nodes of the bus.