FieldServer Driver – Serial
Data Aire DART
|Baud Rates:||2400 (Dart III)/ (9600 intelli-DART/Dart IV)|
The Dart Driver is capable of direct connection to a Data Aire DART device. This driver has been modified for use on intelli-DART units which operate differently than previous DART units.
The FieldServer is connected to the RS-232 serial port of the Dart. The Fieldserver can read and write but active polling must be minimized as in reduces the amount of time that a DART spends controlling the networked devices. The driver operates primarily as a passive client listening to echoes of the data being polled by the DART. The DART must be set to ‘Echo’ mode on the front panel of the Dart for the driver to operate correctly. There is no alternative to this essential but manual setup-step.
The intelli-DART driver is not passive, and is required to poll the intelli-DART units for DAP data after login. Logins are required on the initial poll, after 20 minutes, and if polls for data fail.
The driver is not suitable for direct connection to a network of Data Aire DAP or Chiller devices. A different driver (DAP driver) is provided by FieldServer Technologies for this type of connection.
The driver may be configured very simply, storing all the data obtained from each field device in a large array. A simple one line configuration tells the driver to store ‘everything’. The driver manual identifies the location in the array of each data field. Advanced configuration are also possible.
The driver can write set points and other data to the DAP devices connected to the network. It does this by communicating with the DART which passes the messages onto the DAP devices. A consequence of this, is that for a period of time the DART suspends its control and management of the DAP devices.
The driver is capable of storing all data available from the following devices if they are connected to the DART.
|3||Yes||046 2 modchiller|
|4′||Yes||046 3 modchiller|
|5||Yes||048 DAP,80-character display|
|6||Yes||049 DAP,16-character display|
|7||Yes||080 DAP II, norelay expansion|
|8||Yes||080 Chiller II|
|9||Yes||080 DAP II,with relay expansion|
|E||Yes||080 DAP II,with analog module|
|F||Yes||080 DAP II,with relay and analog|
|Driver is capable of storing DART status/config data but in its current version cannot extract specific data fields.||DART II, III|
Performance Issues: DART only
Inter-message timing constraints and overhead requirements for active messages in a Dart configuration add significant time to each transaction.
When used with a DART device, writing to a set point (or other variable) may take up to 8 seconds to complete the transaction. The results of the write will not be seen until the DART has timed-out back into control mode and echoes the new data to the Fieldserver. This could take several minutes if there are many devices on the loop and will take at least 30 seconds.
When writing continuously, with DART configurations, the minimum time interval between successive writes is 2 minutes.