Varec 8315 Series Protocols, Data Scanning Task, Database Manager, System Tasks, COM0 and COM1

8315 L&J Tankway Software Description TankGate Interface

4.1.4Communications

There are two communications tasks - one for each of the communication channels. COM ports 0 and1 are used to interface to external devices or host systems. Refer to the Hardware Chapter for the location of these ports.

COM0 and COM1

COM 0 and 1 can be configured for communications to Host systems using a variety of protocols. For COM 0 and 1 the communication interfaces include the following:

•RS-485 for use in multi-drop configurations or long cable runs (or both)

•RS-232 for flexibility in configuring other types of communications links such as radio and fiber optic interfaces

•RTS/CTS lines are available for hardware handshaking.

4.1.5Protocols

The TankGate is fully compatible with FuelsManager® software. It is also compatible with a variety of other Host systems including through Modbus protocol.

The default communication settings for the COM ports are as follows:

COM Port	Protocol	Baud Rate	Data Bits	Parity	Stop Bits
COM0	RTU Slave or	9600	8	N	0
	Modbus - Auto-
	sensing
COM1	Modbus	9600	8	N	0

4.1.6Data Scanning Task

The Data Scanning Task is dedicated to the scanning of field input data from tank gauges. The input data is stored in arrays that are subsequently accessed by the Point Executive.

4.1.7Database Manager

The Database Manager is a collection of programs and data. The Database Manager allows the TankGate system executive to access data from the database in an organized and program-independent manner. It resides in non-volatile RAM.

The Database Manager also contains a Database Dictionary. This dictionary describes how the database is organized and also provides information describing how data should be presented to the operator.

After power-up or system reset, a CRC verification of each point in the database is performed. If the CRC does not have a match for the point, then it is disabled and a flag is set indicating that the point is invalid.

4.1.8System Tasks

System tasks include the Calendar Task, which manages Time and Date functions. Other system tasks include utility routines for checksum calculations, diagnostics, start-up and initialization.

22 Installation and Operations Manual