Introduction
The IGSS software package offers an interface for real time data presentation in Microsoft Excel. The interface installs automatically during the normal IGSS installation procedure and is ready to run. This topic describes how to use the real time data (RTD) interface from Microsoft Excel.
The RTD interface was introduced with Microsoft Excel 2002 and thus cannot be used with earlier versions of Excel.
Syntax and examples
The IGSS real time data module is invoked from Microsoft Excel by using the built-in RTD() function. The general syntax for using this function with IGSS real time data is:
RTD("IGSS.RTD";<ServerName>;<ObjectName>;<AtomName>)
The first argument “IGSS.RTD” specifies the progID of the IGSS RTD module. This is a fixed string that should always be set to “IGSS.RTD”.
The second argument is optional. It is the name of the server containing the IGSS RTD module. Normally the IGSS RTD module will be running locally and in this case the second argument can be omitted. If the IGSS RTD module is installed on another PC, then the computer name of this PC should be specified.
If the IGSS RTD module is running on another PC, the IGSS RTD client connects to the IGSS RTD server using the integral security mechanism in Windows called DCOM (Distributed COM). Please refer to the Microsoft Web Site or the OPC Foundation Web Site for further details.
The third argument <ObjectName> is the name of the IGSS object to be connected for real time data updates.
The fourth argument <AtomName> is the name of the atom to get real time data from.
All arguments can be specified as cell references. Examples of this can be viewed in the sample "IGSS Real Time Data Microsoft Excel" file associated with the IGSS Demo configuration.
Examples:
Get actual value from IGSS analog object q1:
RTD("IGSS.RTD";;"q1";"value")
Get state value from IGSS digital object m1:
RTD("IGSS.RTD";;"m1";"state")
Get table index 7 from IGSS table object tab1:
RTD("IGSS.RTD";;"tab1";"Index 7")
Requirements and limitations
The real time data function is supported by Microsoft Excel XP or higher.
The IGSS RTD Server requires .NET platform version 1.1 to be installed. This component is automatically installed by IGSS.
The server tries to update subscribing objects every 2 seconds. The RTD server uses a push/pull mechanism which ensures that the RTD server only writes data updates to Excel when Excel is ready to receive.
List of atom names
The table below shows atom names for all IGSS object types:
| Analog | Digital | Counter | Table | String |
|---|---|---|---|---|
| High alarm | State | Counter | Index 0 | String |
| High limit | Command | Counter limit | Index 1 | |
| Value | Ana value | Preset | Index 2 | |
| Setpoint | Command | Index 3 | ||
| Low limit | Index 4 | |||
| Low alarm | Index 5 | |||
| High scale | Index 6 | |||
| Low scale | Index 7 | |||
| Index 8 | ||||
| Index 9 |