S7 Device Plugin

The linked devices can simply be controlled using CoDaBix®. By linking the PLC memory to the Nodes defined in CoDaBix® the PLC can directly interact with many other Nodes, devices, services, etc. maintained in CoDaBix®. Also other CoDaBix® participants can interact with the PLC devices linked through the S7 Device Plugin.

• Dynamic generation of manufacturing jobs based on different conditions and data produced by machines, users, orders, condition, services, etc.
• Additional reliability by monitoring the whole plant including inter-plant interaction
• Centralized controller and flow surveillance for early diagnosis of possible failures
• Possibilities to improve the Shop Floor Management by monitoring and recording production data produced by the devices

Channel Element
The Channel element serves as the container for the elements Settings and Variables. One channel identifies one PLC connection to which the channel configuration belongs. This information is therefore used by the S7 Device Plugin to link the PLC to CoDaBix®.

The Channel element can look as follows:

<Channel>
  <Settings />
  <Variables />
</Channel>

Settings Element
The Settings element defines the attributes to setup the channel. These attributes configure the channels connection parameters.

The Settings element can look as follows:

<Settings Address="192.168.0.80"
          Rack="0"
          Slot="2"
          ChannelType="OperationPanel"
          DeviceType="S7400" />

The Settings element provides the following list of attributes:

S7 Device Channel Type

The following values are valid for attributes of that type:

S7 Device Type

The following values are valid for attributes of that type:

Variables Element
The Variables element serves as the container for one or more Variable elements. This element maintains all variables associated with the channel.

The Variables element can look as follows:

<Variables>
  <!-- 0-n Variable elements -->
</Variables>

Variable Element
The Variable element serves as the container for the element Variables. One variable identifies one addressable area in the memory of the PLC or a set of subsequent variables identify multiple addressable areas in the memory of the PLC. This information is therefore used by the S7 Device Plugin to link the PLC memory to CoDaBix® Nodes.

Each Variable element provides the following list of attributes:

PLC Variable Type

The following values are valid for attributes of that type:

PLC Variable Address

The following Operand and Data Type combinations are valid to construct a valid PLC variable address:

Operands

Data Types

Examples

The Variable element can look as follows:

<Variable Name="Active Rotations"
          Type="DInt"
          Address="DB101.DBD 0" />

The Variable element with the Type attribute and the attibute value “Object” can look as follows:

<Variable Name="Mill Job No. 1" Description="Identifies the mill job no. 1" Type="Object">
  <Variables>
    <Variable Name="Rotations" Type="DInt" Address="DB200.DBD 0" />
    <Variable Name="Use Colling" Type="Bool" Address="DB200.DBX 4.0" />
    <Variable Name="Use Fan" Type="Bool" Address="DB200.DBX 4.1" />
    <Variable Name="Point 1" Type="Object">
      <Variables>
        <Variable Name="X" Description="The x portion of the drill." Type="Int" Address="DB200.DBW 5" />
        <Variable Name="Y" Description="The y portion of the drill." Type="Int" Address="DB200.DBW 7" />
      </Variables>
    </Variable>
    <Variable Name="Point 2" Type="Object">
      <Variables>
        <Variable Name="X" Description="The x portion of the drill." Type="Int" Address="DB200.DBW 9" />
        <Variable Name="Y" Description="The y portion of the drill." Type="Int" Address="DB200.DBW 11" />
      </Variables>
    </Variable>
    <Variable Name="Point 3" Type="Object">
      <Variables>
        <Variable Name="X" Description="The x portion of the drill." Type="Int" Address="DB200.DBW 13" />
        <Variable Name="Y" Description="The y portion of the drill." Type="Int" Address="DB200.DBW 15" />
      </Variables>
    </Variable>
  </Variables>
</Variable>

It is recommended to use a professional XML editor when editing the configuration file manually. To also benefit from the XML scheme definition mentioned at the end of this article you have to refer to the scheme definition by using the xsi:noNamespaceSchemaLocation attribute in the document root element PluginSettings as follows (the XSD file needs to be placed next to the XML file):

<?xml version="1.0" encoding="utf-8" ?>
<PluginSettings xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                xsi:noNamespaceSchemaLocation="CoDaBix.S7DevicePlugin.Settings.xsd">
  <!-- child elements -->
</PluginSettings>

Independent from editing / creating the configuration file manually or automated, the element tree above documented must be fulfilled to produce a valid, well-formed and usable configuration file.

An S7 XML Configuration file is assigned to a S7 Device Channel in CoDaBix for automatic synchronization, if the following condition is true:

• A file with the name CoDaBix.S7DevicePlugin.<ChannelName>.Settings.xml exists in the ConfigFolder (<CodabixProjectDir>/plugins/S7DevicePlugin) when starting the S7 Plugin (i.e. when starting CoDaBix) or when creating a new channel in CoDaBix.

In that case, once the configuration file changes, it is automatically synchronized into CoDaBix. Also, when the variables in CoDaBix (or the channel settings) are changed, the changes are synchronized into the configuration file.

Regardless of the automatic synchronization, you can also use manual synchronization by right-clicking on a S7 Device Channel in CoDaBix and selecting the corresponding Import/Export menu item.

CoDaBix.S7DevicePlugin.Settings.xml

<?xml version="1.0" encoding="utf-8"?>
<PluginSettings>
  <Channel>
    <Settings Address="192.168.0.80" ChannelType="OperationPanel" DeviceType="S7400" />
    <Variables>
      <Variable Name="Active Job Name" Type="String" Address="DB100.DBB 0" Length="64" />
      <Variable Name="Active Job Number" Type="String" Address="DB100.DBB 80" Length="8" />
      <Variable Name="Active Rotations" Type="DInt" Address="DB101.DBD 0" />
      <Variable Name="Mill Job No. 1" Description="Identifies the mill job no. 1" Type="Object">
        <Variables>
          <Variable Name="Rotations" Type="DInt" Address="DB200.DBD 0" />
          <Variable Name="Use Colling" Type="Bool" Address="DB200.DBX 4.0" />
          <Variable Name="Use Fan" Type="Bool" Address="DB200.DBX 4.1" />
          <Variable Name="Point 1" Type="Object">
            <Variables>
              <Variable Name="X" Description="The x portion of the drill." Type="Int" Address="DB200.DBW 5" />
              <Variable Name="Y" Description="The y portion of the drill." Type="Int" Address="DB200.DBW 7" />
            </Variables>
          </Variable>
          <Variable Name="Point 2" Type="Object">
            <Variables>
              <Variable Name="X" Description="The x portion of the drill." Type="Int" Address="DB200.DBW 9" />
              <Variable Name="Y" Description="The y portion of the drill." Type="Int" Address="DB200.DBW 11" />
            </Variables>
          </Variable>
          <Variable Name="Point 3" Type="Object">
            <Variables>
              <Variable Name="X" Description="The x portion of the drill." Type="Int" Address="DB200.DBW 13" />
              <Variable Name="Y" Description="The y portion of the drill." Type="Int" Address="DB200.DBW 15" />
            </Variables>
          </Variable>
        </Variables>
      </Variable>
    </Variables>
  </Channel>
</PluginSettings>

CoDaBix.S7DevicePlugin.Settings.xsd

<?xml version="1.0" encoding="utf-8"?>
<xs:schema id="CoDaBix.S7DevicePlugin.Settings"
           elementFormDefault="qualified"
           xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:simpleType name="Guid">
    <xs:restriction base="xs:string">
      <xs:pattern value="([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12})|(\{[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}\})"/>
    </xs:restriction>
  </xs:simpleType>
 
  <xs:simpleType name="PlcAddress">
    <xs:restriction base="xs:string">
      <xs:pattern value="^[ \t]*((DB[ \t]*([\d]+)[ \t]*\.[ \t]*(DB))|(((Z|C)|DB|M|(E|I)|L|(A|Q)|(PE|PI)|(PA|PQ)|T)))[ \t]*((X|B|W|D))?[ \t]*([\d]+)(\.([\d]+))?\b" />
    </xs:restriction>
  </xs:simpleType>
 
  <xs:simpleType name="VariableEnumType">
    <xs:restriction base="xs:string">
      <xs:enumeration value="Bool" />
      <xs:enumeration value="Byte" />
      <xs:enumeration value="Char" />
      <xs:enumeration value="Int" />
      <xs:enumeration value="Word" />
      <xs:enumeration value="DInt" />
      <xs:enumeration value="DWord" />
      <xs:enumeration value="Real" />
      <xs:enumeration value="Double" />
      <xs:enumeration value="Date" />
      <xs:enumeration value="Time" />
      <xs:enumeration value="TimeOfDay" />
      <xs:enumeration value="S5Time" />
      <xs:enumeration value="DateTime" />
      <xs:enumeration value="String" />
      <xs:enumeration value="S5String" />
    </xs:restriction>
  </xs:simpleType>
 
  <xs:complexType name="VariableType">
    <xs:sequence>
      <xs:element name="Variables" type="VariablesType" minOccurs="0" maxOccurs="1" />
    </xs:sequence>
 
    <xs:attribute name="Identifier" type="Guid" use="required" />
    <xs:attribute name="Name" type="xs:string" use="required" />
    <xs:attribute name="Description" type="xs:string" use="optional" />
    <xs:attribute name="Address" type="PlcAddress" use="optional" />
    <xs:attribute name="Type" type="VariableEnumType" use="required" />
    <xs:attribute name="Length" type="xs:integer" use="optional" default="-1" />
  </xs:complexType>
 
  <xs:complexType name="VariablesType">
    <xs:sequence>
      <xs:element name="Variable" type="VariableType" minOccurs="0" maxOccurs="unbounded" />
    </xs:sequence>
  </xs:complexType>
 
  <xs:simpleType name="ChannelDeviceEnumType">
    <xs:restriction base="xs:string">
      <xs:enumeration value="Logo" />
      <xs:enumeration value="S7200" />
      <xs:enumeration value="S7300" />
      <xs:enumeration value="S7400" />
      <xs:enumeration value="S71200" />
      <xs:enumeration value="S71500" />
    </xs:restriction>
  </xs:simpleType>
 
  <xs:simpleType name="ChannelEnumType">
    <xs:restriction base="xs:string">
      <xs:enumeration value="OperationPanel" />
      <xs:enumeration value="ProgrammerDevice" />
      <xs:enumeration value="Other" />
    </xs:restriction>
  </xs:simpleType>
 
  <xs:complexType name="ChannelSettingsType">
    <xs:attribute name="Address" type="xs:string" use="required" />
    <xs:attribute name="Rack" type="xs:integer" use="optional" default="0" />
    <xs:attribute name="Slot" type="xs:integer" use="optional" default="2" />
    <xs:attribute name="ChannelType" type="ChannelEnumType" use="optional" default="OperationPanel" />
    <xs:attribute name="DeviceType" type="ChannelDeviceEnumType" use="optional" default="S7300" />
  </xs:complexType>
 
  <xs:complexType name="ChannelType">
    <xs:sequence>
      <xs:element name="Settings" type="ChannelSettingsType" minOccurs="0" maxOccurs="1" />
      <xs:element name="Variables" type="VariablesType" minOccurs="0" maxOccurs="1" />
    </xs:sequence>
  </xs:complexType>
 
  <xs:complexType name="PluginSettingsType">
    <xs:sequence>
      <xs:element name="Channel" type="ChannelType" minOccurs="0" maxOccurs="1" />
    </xs:sequence>
  </xs:complexType>
 
  <xs:element name="PluginSettings" type="PluginSettingsType" />
</xs:schema>

• Add a new Channel in the left list by clicking the upper plus button.
  • Set the name of the channel by clicking its name in the right pane.
  • Set up the Channel Settings like the IP Address (at least required).
  • Optionally set the appropriate Device Type and select the Channel Type to be used.
  • Optionally set the Rack and Slot (in case it differs from the defaults).
• Add a new Variable to the Channel in the second from the left list by clicking the upper first button with the plus sign.
  • Set up the name of the variable by clicking its name in the right pane.
  • Optionally set the description of the variable by clicking in the free area beneath the variable name.
  • Set up the PLC address operand to be used to access the PLC memory for that variable.
  • Set up the PLC variable type in the combo and enter, in case of a string or an array (check the option Is Array) variable, the appropriate length of the variable.
  • Optionally add additional variables in case the previously added variable is of the type “Object”. Do that by selecting the object variable in the left tree and then click the second add button with the plus sign above.
• To remove a variable, select it in the tree and click on the button with the minus sign above.
• To remove a channel, select it in the left list and click on the button with the minus sign above.
• Using the Import Project button it is possible to import the following project formats:
  • STEP7 Project Files (*.s7p)
  • IP-S7 Project Files (*.ips7)
  • S7 Watch Project Files (*.wproj)
  • CSV-to-S7 Project Files (*.ini)

The plugin's device type S7Device also defines the S7DeviceChannel and therefore extends the basic CodabixDevice and CodabixDeviceChannel entities. While the S7Device just represents a concretization of the CodabixDevice, the S7DeviceChannel extends the CodabixDeviceChannel with the S7 Variable Entities.

Each channel is handled by a Channel Worker which establishes a physical connection to the S7 device. For diagnostic purposes, the worker automatically reads the PLC address “MB 0” every 10 seconds to update the status code of the Channel and description to detect connection failures.

By default, the worker does not read any values. When a client or plugin requests a synchronous read of the Channel variables in CoDaBix (e.g. using the CoDaBix Web Configuration's function “Read actual value”), the channel worker reads them from the underlying S7 device and then writes them into the corresponding CoDaBix Nodes.

Similarly, when a Client or plugin writes values into the channel's variables, the channel worker will write those values to the underlying S7 device.

To have an S7 variable being read steadily, you can edit the Node in the CoDaBix Web Configuration and set “History Options” to Yes (which will create an internal subscription), or you can use e.g. a OPC UA Client connected to the OPC UA Server plugin and create a subscription for the S7 variable Nodes. In these cases, the channel worker reads the variables from the S7 at a regular interval and, if the value of one of the variables has changed, writes the new value into the corresponding CoDaBix Node.

Each S7 variable can access the same PLC memory using the same PLC address operand. However, its interpretation depends on the PLC Data Type selection. Supported variable formats are scalar, array and object variables. Variables of the type Object can own further variables and are defined as UserDefinedTypes (UDT in STEP7).