# 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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