BASEstartm Open DAS
for Allen-Bradley Data Highwaytm
on Tru64tm UNIX
Installation and User's Guide
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3.2.3 Read and Write Data Point Functions

Use the read data point and write data point functions to read data from and write data to a device in a device independent way.

Table 3-4 lists the read and write data point functions available through the BASEstar Open (CLI) interface and BASEstar Open (API) interface.

Table 3-4 Read and Write Data Point Interface Access
Interface Function Name
CLI GET VALUE DATA_POINT
  PUT VALUE DATA_POINT
API bstr_data_point_get_value
  bstr_data_point_put_value

Example 3-4 shows examples of creating a device data point using the CREATE DEVICE_DATA_POINT command.

Example 3-4 DEVICE_DATA_POINT CREATE Command 

BSTR> CREATE DEVICE_DATA_POINT /plc_2_15/p1 \
                    -DATATYPE UNSIGNED_16 \
                    -UPDATE_POLICY SOLICITED \
                    -ACCESS_POLICY ALWAYS \
                    -DEVICE_ACCESS RDWR \
                    -VMD_NAME plc_2_15 \
                    -VAR_NAME p1 \
                    -VAR_CLASS UNNAMED
BSTR> CREATE DEVICE_DATA_POINT /plc_3/p1 \
                    -DATATYPE INTEGER_16 \
                    -UPDATE_POLICY SOLICITED \
                    -ACCESS_POLICY ALWAYS \
                    -DEVICE_ACCESS RDWR \
                    -VMD_NAME plc_3 \
                    -VAR_NAME p1 \
                    -VAR_CLASS UNNAMED
BSTR> CREATE DEVICE_DATA_POINT /plc_5_40/p1 \
                    -DATATYPE BIT \
                    -UPDATE_POLICY SOLICITED \
                    -ACCESS_POLICY ALWAYS \
                    -DEVICE_ACCESS RDWR \
                    -VMD_NAME plc_5_40 \
                    -VAR_NAME p1 \
                    -VAR_CLASS UNNAMED
BSTR> CREATE DEVICE_DATA_POINT /plc_5_40/p2 \
                    -DATATYPE WORD_ARRAY_10 \
                    -UPDATE_POLICY SOLICITED \
                    -ACCESS_POLICY ALWAYS \
                    -DEVICE_ACCESS RDWR \
                    -VMD_NAME plc_5_40 \
                    -VAR_NAME p2 \
                    -VAR_CLASS UNNAMED
BSTR> CREATE DEVICE_DATA_POINT /plc_5_40/p3 \
                    -DATATYPE PLC_5_COUNTER \
                    -UPDATE_POLICY SOLICITED \
                    -ACCESS_POLICY ALWAYS \
                    -DEVICE_ACCESS RDWR \
                    -VMD_NAME plc_5_40 \
                    -VAR_NAME p3 \
                    -VAR_CLASS UNNAMED
BSTR> CREATE DEVICE_DATA_POINT /slc_5_04/p1 \
                    -DATATYPE INTEGER_16 \
                    -UPDATE_POLICY SOLICITED \
                    -ACCESS_POLICY ALWAYS \
                    -DEVICE_ACCESS RDWR \
                    -VMD_NAME slc_5_04 \
                    -VAR_NAME p1 \
                    -VAR_CLASS UNNAMED

Example 3-5 shows the information displayed when you enter the GET VALUE DATA_POINT command.

Example 3-5 DATA_POINT GET VALUE Output 

BSTR> GET VALUE DATA_POINT /plc_5_40/p1
20
BSTR> GET VALUE DATA_POINT /plc_5_40/p2
array[10] of INTEGER_16 
  [ 0]: 0 
  [ 1]: 0 
  [ 2]: 0 
  [ 3]: 0 
  [ 4]: 0 
  [ 5]: 0 
  [ 6]: 0 
  [ 7]: 0 
  [ 8]: 0 
  [ 9]: 0
BSTR> GET VALUE DATA_POINT /plc_5_40/p3
structure PLC_5_COUNTER 
{ 
  CONTROL: 0 
  PRE: 0 
  ACC: 0 
}

Example 3-6 shows the information displayed when you enter the PUT VALUE DATA_POINT command.

Example 3-6 DATA_POINT PUT VALUE Output 

BSTR> PUT VALUE DATA_POINT /plc_5_40/p1
(Bit) : 1
BSTR> PUT VALUE DATA_POINT /plc_5_40/p2
array[10] of INTEGER_16 
  [ 0]: (Integer 16) : 1
  [ 1]: (Integer 16) : 2
  [ 2]: (Integer 16) : 3
  [ 3]: (Integer 16) : 4
  [ 4]: (Integer 16) : 5
  [ 5]: (Integer 16) : 6
  [ 6]: (Integer 16) : 7
  [ 7]: (Integer 16) : 8
  [ 8]: (Integer 16) : 9
  [ 9]: (Integer 16) : 10

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