2  Description

2.1  Introduction

The Anybus X-gateway consists of two Anybus fieldbus or Ethernet network interface modules and an intelligent gateway platform which transfers data between the two networks.
The X-gateway can be configured via a USB port using a Windows-based application, Anybus Configuration Manager. The on-board network interfaces are normally configured from the respective networks, using third-party configuration tools.
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Fig. 1  Anybus X-gateway concept overview
This document describes only the gateway platform. The network interfaces are described in their own documentation.

2.2  Data Exchange

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Fig. 2  Anybus X-gateway data exchange
The terminology and definitions used for different types of data vary between different network types. Most networks distinguish between fast, cyclical I/O data, and less time-critical acyclic data. In the Anybus X-gateway these types of data are generally referred to respectively as I/O Data and Parameter Data.
Each of the two network interfaces exchanges data on its network through its own buffer, which can hold up to 512 bytes of data. The actual amount of data that can be exchanged depends on the settings in the network interface and may therefore be significantly less than 512 bytes, which is only the maximum size of the buffer. The default setting is 20 bytes in each direction. See the documentation for the respective network interface for more information.
In addition to the I/O data the buffers may contain network status information and instructions for controlling the network interface. Depending on the type of network interface this may be general diagnostic information (Status Word), a list of the active slaves (Live List), or other network-specific information. In a network master, part of the buffer may be used to start/stop data exchange and to reset the gateway (Control Word).
The exchange of data between the buffers is separate from the network data exchange. While the X-gateway ensures data consistency (where applicable), it does not feature any mechanisms for synchronisation between the two networks.

2.3  Status and Diagnostics

2.3.1 Status Word

Runtime status and diagnostic information can be provided through the Status Word, which (if enabled) takes up the first two bytes of the output area (data to the network).
The Status Word is disabled by default and must be enabled for each network separately through Anybus Configuration Manager.
(MSB)
                       
(LSB)
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
Gateway Cycle Counter
General Error Counter
(reserved)
Master Mode
Init
Run

Gateway Cycle Counter

A 4-bit counter, incremented for each successful gateway cycle (each time data has been successfully transferred between the network interfaces).

General Error Counter

A 4-bit counter, incremented each time the throughput of the gateway exceeds 100 ms.

Master Mode (master configurations only)

If a network interface is confgured as a network master, these bits indicate the current operation mode of the master to the other network.
The exact definition depends on the network interface type. See the documentation for the respective interface for more information.

Init

Indicates if the other network interface has been initialized.
Bit set (1) = Other network interface successfully initialized
Bit cleared (0) = Could not initialize other network interface

Run

Indicates the status of the data exchange on the other network.
Bit set (1) = Other network is online and exchanging data
Bit cleared (0) = Other network is offline or not exchanging data

2.3.2 Live List (Master Configurations Only)

The Live List provides the active status of the slaves associated with an on-board network interface acting as master. The list is assembled by the master interface and forwarded to the other network each gateway cycle.
The Live List functionality is disabled by default and must be enabled for the master interface through Anybus Configuration Manager.
Offset
bit 0
bit 1
bit 2
bit 3
bit 4
bit 5
bit 6
bit 7
0
Slave 0
Slave 1
Slave 2
Slave 3
Slave 4
Slave 5
Slave 6
Slave 7
1
Slave 8
Slave 9
Slave 10
Slave 11
Slave 12
Slave 13
Slave 14
Slave 15
2
Slave 16
Slave 17
Slave 18
Slave 19
Slave 20
Slave 21
Slave 22
Slave 23
3
Slave 24
Slave 25
Slave 26
Slave 27
Slave 28
Slave 29
Slave 30
Slave 31
4
Slave 32
Slave 33
Slave 34
Slave 35
Slave 36
Slave 37
Slave 38
Slave 39
5
Slave 40
Slave 41
Slave 42
Slave 43
Slave 44
Slave 45
Slave 46
Slave 47
6
Slave 48
Slave 49
Slave 50
Slave 51
Slave 52
Slave 53
Slave 54
Slave 55
7
Slave 56
Slave 57
Slave 58
Slave 59
Slave 60
Slave 61
Slave 62
Slave 63
Bit set (1) = Slave active
Bit cleared (0) = Slave not active
The exact definition of each set or cleared bit depends on the network interface used. See the documentation for the respective interface for more information.

2.3.3 Network-specific Status

Some network interfaces may provide additional registers or status lists. See the documentation for the respective interface for more information.

2.4  Controlling the X-gateway from the Network

Some functions in the X-gateway can be controlled from the network by setting the corresponding bits in the Control Word, which (if enabled) takes up the first two bytes of the input area (data coming from the network).
The Control Word is disabled by default and must be enabled for each network separately via Anybus Configuration Manager. When enabled, specific actions may be required in order for the X-gateway to start exchanging data.
(MSB)
                       
(LSB)
bit 15
bit 14
bit 13
bit 12
bit 11
bit 10
bit 9
bit 8
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
 
Reset
 
Master Mode
 

Master Mode (master configurations only)

If a network interface is confgured as a network master, these bits indicate the current operation mode of the master to the other network.
The exact definition depends on the network interface type. See the documentation for the respective interface for more information.

Reset

Can be used to reset the Anybus X-gateway.
Bit set (1) = Restart the gateway and re-initialize both network interfaces
Bit cleared (0) = No action

2.4.1 Network-specific Controls

Some network interfaces may provide additional methods of controlling the X-gateway from the network. See the documentation for the respective interface for more information.

2.5  Error Handling

If a network goes offline the X-gateway can either freeze (keep the current value) or clear (set to zero) the data from the network that has gone offline. Which action to take can be selected via Anybus Configuration Manager.

2.6  Data Mapping Examples

Usage of the Control Word, Status Word and Live List affect how data is mapped to the network interfaces in the Anybus X-gateway.
The following generic examples describe typical configurations. The actual representation of data on the network is highly network-specific and is described in the documentation for the respective interface.

Typical Slave-to-Slave Gateway Configuration

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Fig. 3  Slave-to-slave example
This example illustrates how data is mapped in a typical slave-to-slave gateway configuration. The Control Word and Status Word is here enabled for both networks.

Typical Master-to-Slave Gateway Configuration

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Fig. 4  Master-to-slave example
This example illustrates how data is mapped in a typical master-to-slave gateway configuration. The mapping is similar to the slave-to-slave configuration but also features the Live List, which indicates the active status of the slaves that are attached to the master interface.