The DataPort driver provides a gateway to CCN devices. This driver polls the DataPort device which in turn reads data from the Carrier Communications Network (CCN) devices. Up to 15 system elements may be connected to a DataPort Device. Carrier limits the number of CCN devices that can polled from a DataPort Device and also limits the data that can be transferred between some CCN devices and the DataPort device. For information on these limitations please consult the Carrier Corporation.
The driver is an active client driver. This means that it initiates read polls with the DataPort device which is expected to provide responses. Server functionality is provided by the driver too.
The driver is configured to allow a single data table (usually the Display Table) to be read from the CCN devices via the DataPort device. As the table typically contains more than one data element, the retrieved data is stored in a number of consecutive data array locations in the FieldServer. The driver can provide descriptions for each of the table values retrieved.
The driver has no advanced knowledge of the CCN devices and their data tables. This means that the driver handles each table in a generic way, without regard for the particular variables that constitute the tables. The most important consequence of this is that the variable values are stored in the order in which they appear in the response from the DataPort device. It isn’t possible to map particular variable values to particular locations in the FieldServer data arrays.
Formal Driver Type
|Connection type:||RS-232 or RS-485 (Two wire, Half-Duplex)|
|Baud Rates:||1200; 2400; 4800; 9600; (Vendor limitation)|
|Data Bits:||8 (vendor limitation)|
|Stop Bits:||1 (vendor limitation)|
|Parity:||None (vendor limitation)|
|CEPL130363-01 ER: CESR121289-08||Factory|
Only one DataPort device can be connected to each RS-232 or RS-485 (with converter) port at a time. This limitation arises from the fact that the message format is node-less; there is insufficient information in one message to differentiate messages from one DataPort device or another.
Communications functions – Supported functions at a glance:
Data Types Supported
The driver has no advance knowledge of the number, names , length and contents of any of the data tables to be found in the CCN devices. (These parameters are dependent on the CCN devices). Therefore the drive handles all table variable values as one of the following types; a) numeric values b) occupancy strings c) time values or discrete state’s converted to a numeric value. The driver chooses the data type automatically based on the response from the DataPort device.
Limitations and Exclusions
The driver is not capable of configuring the DataPort device. Software provided by the Carrier Corporation is required to do this. The DataPort device requires configuration, so it connects to the appropriate CCN devices on the CCN communications network.
The Carrier DataPort driver does not support the following functions. Send Data Periodically, Stop Sending, Xoff, Xon, Omit 24 Character description, Include 24 Character description, Read Configuration.
The Carrier DataPort device is a read only device.
Other limitation and exclusions are described in the driver manual.