Page 12 of | Page 12 of 29 |
4.4.4.Map Descriptor Example 1 – Simple Read
This example provides a Map Descriptor to read 10 bytes of Discrete Input states, starting at the very first Discrete Input. The data is stored in a Data Array called DA_DI and the first input is stored at location 100 in the array (101st element). The PLC is polled every 2 seconds
Map_Descriptor_Name, | Data_Array_Name, | Data_Array_Offset, | Function, | Node_Name | Address | Length | Scan_Interval, | Data_Type |
Read D1, | DA_D1, | 100, | RDBC, | 1, | 10, | .0, | %1 | |
|
|
|
|
|
|
|
|
|
Map Descriptor names may be used in driver error messages. It is not essential, but it is useful to use unique names.
Location in the Data Array where the first element of data will be stored. The arrays are zero referenced so an offset of 100 indicates the 101st element of the array.
The Node must
have been defined in the Nodes section of the CSV file. The Node Name connects this Map Descriptor to a Node which
The address and length specify the first element and the number of elements that must be read from the PLC’s data tables. GE PLC’s reference data tables starting at element 1.
Read will be performed every 2.0s.
Use the % symbol
The name of the Data Array in which the driver will store the data. The name must correspond to a Data Array defined in the Data Array section of the CSV file
RDBC = read block continuous. The driver will read data from the PLC continuously.
in turn connects
the Map Descriptor to a port.
Unless otherwise specified, the driver reads bytes and words. This Map Descriptor reads bytes of data covering %I1 to %I79
as you would if you were programming a
GE PLC.
4.4.5.Map Descriptor Example 2 – Simple Write
This example writes data from the FieldServer Data Array called DA_AO to the PLC identified as NODE1. The write is repeated every 5 seconds. Ten word values are written to the PLC’s %AQ Data Table starting at location 20.
Map_Descriptor_Name, | Data_Array_Name, | Data_Array_Offset, | Function, | Node_Name | Address | Length | Scan_Interval, | Data_Type |
Write_AO, | DA_AO, | 0, | WRBC, | Node1, | 20, | 10, | 5.0, | %AQ |
|
|
|
|
|
|
|
|
|
Write continuously | Write to PLC Table element number 20 to | |
29 inclusive (10 elements) | ||
|
Write to the %AQ (Analog Output) table in the PLC.
FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldServer.com Tel: (408)