Справочник Пользователя для Varec 8315 Series

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8300

8315 L&J Tankway Software Description

The LJ1000 point provides an interface to L&J MCG1000 Direct Digital Gauges.  L&J 

Model 1000 Tank gauge transmitters are connected directly to a Model 8315 Tank 

Gauge Interface Module.  The Model 8315 is automatically detected at startup, and an 

LJSCAN point is automatically created to manage the scanning task.  The Module 

parameter determines which Model 8315 will be used.  The ID must match the unit 

address of the MCG 1000.

Scanning begins when the Module is assigned.  The DevType must match the 

configuration of the transmitter.  Conversion from English to Metric can be performed 

be setting the LevelConvert and the TempConvert parameters in the LJSCAN point 

associated with the LJ1000 point.

Filtering is performed using the LevelFilter and TempFilter parameters of the associated 

LJSCAN point.  If a change in level greater than the LevelFilter is read from the gauge, 

the Level parameter is not updated until it has stabilized.  A reading is considered stable 

if it does not change more than the LevelFilter value for the number of readings 

determined by the Filter parameter.  Thus, small changes (less than the LevelFilter) result 

in the Level being updated immediately.  Large changes must pass through the filter and 

will not be seen until the reading stabilizes. The same strategy is applied to the Temp 

parameter value using the TempFilter parameter.  Since the LevelFilter and TempFilter 

are associated with the LJSCAN point, it applies to all LJ1000 and LJ1500 points.  The 

number of readings used in the filter algorithm can be set on an individual basis.  If no 

filtering is desired, set the Filter parameter to 0.

A separate time-out mechanism is employed to assure that the filter does not prevent 

a reading from taking place.  The LJSCAN parameter ScanTimeout is used to set an alarm 

bit in the PntStatus parameter if a good reading does not take place in a specified period 

of time.  If there is no response from the gauge, or if there are constant parity errors, or 

if the level is constantly changing by a value greater than the LevelFilter, then the 0x02 

bit of the PntStatus will be set after the ScanTimeout period elapses.  The ScanTime 

parameter in the LJ1000 point is updated each time a good reading takes place.  If the 

ScanTime differs from the Elapse parameter by more than the ScanTimeout, the 0x02 

bit is set in the PntStatus.