Varec TankGate Interface 8315 Series User Manual

Page 45

8315 TGI

Software Description

Varec, Inc.

Application

The GWBLK point is a look-up table used by the Modbus Slave protocol handler. Up to sixteen

address-point reference pairs may be used per GWBLK point. Multiple GWBLK points may be

used if necessary. The Addr parameter specifies the data address. The corresponding PntRef

parameter specifies the database parameter for the request. The Gateway Block point allows you

to use the 8300 series Tank Gate Interface easily in retrofit applications. It is not necessary to

re-configure an existing HMI or Host system. You can configure the 8300 series Tank Gate

Interface to match the addresses used in the Host system.

When the Modbus Slave protocol handler receives a request, it searches the GWBLK points to

determine if any of the Addr parameters match the request. If a match is found, the data

referenced by the PntRef parameter will be used for the response.

There are three data modes: DataMode=0, which returns the data in the default format, and

DataMode=1, which returns the data in an integer format. DataMode=1 will scale IEEE floating

point data to an integer value, using the Offset, Scale, ValueMin and ValueMax parameters. If

DataMode = 4, the data will be scaled to an integer by multiplying the data value times the Scale

parameter.

DataMode

Integer HEX value that controls the data returned to a Modbus Host
0: Use parameter values
0x01: Convert to Integer
0x02: Return 0xFF if the data is invalid.
0x04: Convert to Integer using only the Scale
If the DataMode is 0x01, the PntRef data will be converted to an integer

using the Offset, Scale, ValueMin and ValueMax. If the DataMode is 0x04,

the Scale parameter is used to convert to an integer.

RegSet

Offset

Input range Offset used for scaling the output to an integer value when

DataMode=1.

Scale

Input range Scale used for scaling the output to an integer value when

DataMode=1.

ValueMin

Output range Offset used for scaling the output to an integer value when

DataMode=1.

ValueMax

Output range Scale used for scaling the output to an integer value when

DataMode=1.

CommFailValue

Value to set all of the output registers to when there is a communications or

other failure. The CommFailValue works in conjunction with the Filter

values. If the PntStatus of the PntRef has bits set that match the Filter, the

reference value is declared invalid and the output value will be set to the

CommFailValue. This mode is overridden by DataMode = 0x02.

Addr1-10

PntRef1-10

Size1-10

Filter1-10

Addr1 is the Data Address and PntRef1 is the corresponding database

parameter that will be used for a response. The default Size is 1. See the

discussion below for more detail on the Size parameter.
The Filter is used to determine if the data is valid. The PntStatus of the point

specified by the PntRef is read and if there are bits set that match the Filter,

the source data is considered invalid. The output registers will be set to the

value determined by the CommFailValue.

Dynamic Parameters

Function

PntStatus

Byte value indicating status of point Values are:
0: No error

pntCheckSum

CRC-16 Checksum of point's static Configuration Parameters

Configuration Parameters

Function