Extended forms fields
The following fields are implemented with extended forms (press F2).
Determines whether or not the I/O Device is linked to an external data source. If you link to an external data source, CitectSCADA is updated with any changes made to the external data source when a refresh is performed.
If you disconnect an existing link, you can choose to make a local copy of the tags in the database or you can delete them from CitectSCADA's variable tags database altogether.
If an I/O Device is linked to an external data source the Database Type, External Database, Connection String, Tag Prefix and Live Update fields will be greyed out.
The format of the data referenced by the external data source.
The path and filename of the external data source for the I/O Device. Alternatively, you can enter the IP address/directory, computer name, or URL of a data server, etc. (for example "C:\Work.CSV" or "127.0.0.1", "220.127.116.11\HMI_SCADA" or "http://www.abicom.com.au/main/scada" or "\\coms\data\scada").
Click Browse to select a path and filename.
Enter a connection string to provide connection details for the data source. This is similar to an ODBC connection string. For example:
UserID = XXX; Password = YYY
Not every data source needs a connection string.
The prefix that will be inserted in front of the names of linked tags in CitectSCADA's variable tags database (for this I/O Device only). To change the prefix, delete it first, perform a manual refresh, then add the new prefix.
Determines whether the linked tags in CitectSCADA's variable tags database will be updated when the external data source is changed (i.e. you manually change a field, etc.). This refresh will occur the first time you link to the data source, and then whenever you attempt to read the changed variables (for example you compile your project, display the variable using the Variable Tags form, modify or paste the tag, etc.)
Without an automatic refresh, you will need to perform a manual refresh to update the linked tags in CitectSCADA.
Note: This field is only available if you have installed one of the CitectSCADA FastLinx products.
Controls whether or not the linked tags in CitectSCADA and an external tag database will be synchronized if either database is changed. To enable live linking, choose Yes from the Live Update menu.
When Live Update is enabled and the variable tag database is accessed (for example, during project compilation or when a drop-down list is populated), CitectSCADA queries the external tag database to determine if it has been modified. If so, CitectSCADA merges the changes into the local variable tag database. Conversely, any changes made to the local tag variable database will be incorporated automatically into the external tag database.
Enables/disables the logging of writes to the I/O Device. When enabled, writes are logged to the SYSLOG.DAT file in the logs folder of the CitectSCADAUser and Data folder selected during installation, also specified in the INI file as [CtEdit]Logs. See Tag Functions for information about TagWriteEventQue and logging tag data.
Note: Logging writes to every I/O Device may slow communications as the CitectSCADA system will be writing large amounts of data to disk. However, logging of writes is useful when debugging a system.
Enables/disables the logging of reads from the I/O Device. When enabled, reads are logged in the CitectSCADA SYSLOG.DAT file.
Note: Logging reads to every I/O Device may slow communications as the CitectSCADA system will be writing large amounts of data to disk. However, logging of reads is useful when debugging a system.
Enables/disables data caching. When enabled, a cache of the I/O Device's memory is retained at the I/O Server, thus improving communications turn-around time.
Note: Data caching has to be enabled for scheduled I/O Devices, but disabled for memory or disk I/O Devices.
The cache time specified in milliseconds. When caching is enabled, data that is read from a I/O Device is stored temporarily in the memory of the I/O Server. If another request is made (from the same or another client) for the same data within the cache time, the CitectSCADA I/O Server returns the value in its memory - rather than read the I/O Device a second time. Data caching results in faster overall response when the same data is needed by many clients.
A cache time of 300 milliseconds is recommended.
The Cache Time for a scheduled I/O Device is automatically calculated. You can view a scheduled I/O Device's cache time using the Kernel Page Unit command.
Specifies that tags for a particular device are continuously polled at a minimum background poll rate. The options are True or False. Set this field to True if you are operating on a slow network, with a slow device, or where tags may normally only be polled infrequently.
When Background Poll is set to True, specifies the minimum rate by which the device will be polled. You may select any predefined value from the drop-down list, or enter your own in the format of HH:MM:SS. If you do not enter a value, the default value of 30 seconds will be used.
Min Update Rate
The DataSource will send tag update value notifications to subscription clients after a pre-defined period of time expires. You may select any predefined value from the drop-down list, or enter your own in the format of HH:MM:SS. If you do not enter a value, the default value of 0 seconds will be used and no update value notifications will be sent.
Staleness period represents total number of seconds that will elapse after the last update before extended quality of the tag element is set to "Stale". You may select any predefined value from the drop-down list, or enter your own in the format of HH:MM:SS. If you do not enter a value, the default value of 0 seconds will be used and tag elements will not be set to "Stale".
Note: For further information on Minimum Update Rate and Staleness Period refer to Reading and Writing Tags.
Determines whether the I/O Device is configured for scheduled communications. This is normally set using the Express Communications Wizard.
Note: If you do not specify a schedule for a dial-up remote I/O Device, the connection will be established at startup and will remain connected until shut-down.
See Scheduled Communications.
The I/O Server will attempt to communicate with the I/O Device at this time, and then at intervals as defined below. This time is merely a marker for CitectSCADA. If you run up your project after this time, the I/O server will not wait until the next day to begin communicating. It will operate as if your project had been running since before the start time.
Connect Action (254 Chars.)
Cicode to be executed once communication with the I/O Device has been established (and before any read or write requests are processed).
The time between successive communication attempts. The period needs to be long relative to the driver's watchtime and the [Dial]WatchTime. If necessary, decrease these watchtimes or increase Period to help ensure that Period is more than double the watchtimes.
Examples (based on a Synchronize at time of 10:00:00):
Select On Startup for a persistent connection. To disconnect a persistent connection, you need to call the IODeviceControl() function with type 8.
Disconnect Action (254 Chars.)
Cicode to be executed once communication with the I/O Device has been terminated (and after read and write requests are processed).
Phone Number (64 Chars.)
The telephone number that needs to be dialed to initiate contact with the I/O Device. (i.e. for dial-up remote I/O Devices)
Caller ID (32 Chars.)
A unique identifier which identifies a remote I/O Device when it dials back to the I/O Server. The caller ID can be any combination of alpha-numeric characters and/or the character '_' (underscore).
This ID will only be used if the I/O Device initiates the call to the I/O Server. If the modem initiates the call, you need to set the caller ID on the modem.
Note: If you are multi-dropping off a single modem, use your I/O Devices to send the caller ID, not the modem. This is because using the modem to send the ID will send the same ID no matter which I/O Device the call is relevant to. This makes it difficult for you to identify the I/O Device that triggered the call.
By using the I/O Device to send the ID, the I/O Server will receive a unique caller ID for each I/O Device. However, some I/O Devices are not capable of sending caller IDs. If you are multi-dropping, use I/O Devices that can send caller IDs.
Set to TRUE or FALSE to indicate if the persistence of the tag cache file is on or off. Default is TRUE and the data will be written to the XML file as described in "File Name" below. If one of the primary/standby I/O devices (identified by the same network number) has persistence set to FALSE, then every device has it turned off.
Indicates how often to persist the XML cache file to disk. Default is 10 minutes (00:10:00). Normally, the period used is the highest value specified for one of the primary/standby I/O devices (identified by the same network number).
Indicates the path to the file on disk where the XML cache will be stored. You can specify just the path or the path with the actual file name. The default is Data directory using the format <ClusterName>.<IOServerName>.<IODeviceName>.cache. If the location cannot be created, then either the default path, default file name or both is used. Normally, the path used is the first non-empty path specified for one of the primary/standby I/O devices (identified by the same network number).