FieldServer FS-8700-82 Computer Drive User Manual


 
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1. Carrier DataLink Description
The Carrier DataLink driver allows the FieldServer to transfer data to and from devices over
either RS-232 or RS-485 using Carrier DataLink protocol. The FieldServer can emulate either a
Server or Client.
The Carrier DataLink Serial Driver allows variables to be read and written in system elements
connected to a Carrier Comfort Network communication bus. Up to 15 system elements may be
connected to a DataLink Device. Display, Occupancy, Set Point Tables and Carrier Comfort
Network (CCN) variables may be read or written.
The DataLink device provides a gateway to CCN devices. This driver polls the DataLink device
which in turn reads/writes data to the CCN devices.
Carrier limits the number of CCN devices that can polled from a DataLink Device as well as the
data that can be transferred between some CCN devices and the DataLink device. For
information on these limitations please consult the Carrier Corporation.
The driver is an active client driver. This means that it initiates read/write polls with the DataLink
device which is expected to provide responses. Server functionality is not intended to provide
full emulation of DataLink Devices but can be extended on request.
The driver is configured to allow data tables to be read from the CCN devices via the DataLink
device. As the tables typically contain more than one data element, the retrieved data is stored
in a number of consecutive FieldServer data array locations in the FieldServer. The individual
values cannot be scaled before they are stored. The driver can provide descriptions for each of
the table values retrieved. Descriptions are stored in ASCII in a separate data array.
The driver can be configured to read a specific variable from a CNN device and store its value
using optional scaling in a configurable location in a FieldServer data array.
The driver can be configured to write a value (using optional scaling) from a FieldServer data
array to a specific variable in a CNN device, provided that the variable allows its value to be
written.
The driver has no advanced knowledge of the CCN devices and their data tables. Therefore it
cannot validate table names or variable names specified in the configuration file. This means
that the driver handles each table in a generic way, without regard for the particular variables
that constitute the tables.
It is important that you understand the limitations and exclusions of this driver. Refer to Section
5.4 for more information.