You can create EPICS Client I/O servers to monitor process variables that an EPICS server, or input/output controller (IOC), publishes using the Channel Access network protocol. You can create an EPICS Client I/O server to read process variables from and write process variables directly to an IOC using network-published shared variables.
Note Before you can use the EPICS Client I/O server, you first must configure an IOC 3.14 or later server. The configurations of the EPICS Client I/O server and the IOC must match. You can configure the EPICS Client I/O server even when the IOC is not running.The EPICS: Input / Output Controller Application Developer's Guide provides information about configuring an IOC. Refer to the Argonne National Laboratory website at www.aps.anl.gov/epics to download this guide as well as the latest version of EPICS.

Creating EPICS Client I/O Servers Interactively

Complete the following steps to create an EPICS Client I/O server interactively.

  1. In the Project Explorer window, right-click a target, such as the My Computer target, and select New»I/O Server from the shortcut menu.
  2. In the Create New I/O Server dialog box, select EPICS Client and click the Continue button.
  3. In the Configure EPICS Client I/O Server dialog box, click the Add Record button to add a process variable you want to monitor. The Configure EPICS Client I/O Server dialog box organizes process variables first by record and then by field.
    Note NI recommends limiting the number of process variables in one EPICS Client I/O server to 2,000. Create multiple EPICS Client I/O servers if you want to monitor more than 2,000 process variables.
    You also can click the Import File button to load multiple process variables stored in a .db, or record instance, file. You typically create a .db file when you configure an IOC.
    Note When you import multiple process variables, LabVIEW imports only the VAL field of the process variables.
  4. Specify the Name of the record of the process variable you want to monitor. Record names within the same I/O server must be unique.
  5. Select the field of the process variable and specify the Name, Data type, and Access type of the field. Field names under the same record must be unique.
  6. Click the Add Field button if you want to add another field under an existing record.
  7. Repeat steps 3 through 6 for as many process variables as you want to monitor.
  8. Click the OK button.

After you create an EPICS Client I/O server, you can use the View I/O Items dialog box to view the process variables the I/O server monitors. Right-click the I/O server in the Project Explorer window and select View I/O Items from the shortcut menu to display the View I/O Items dialog box.

Creating EPICS Client I/O Servers Programmatically

Complete the following steps to create an EPICS Client I/O server programmatically.

  1. Add the Create EPICS Client VI to the block diagram.
  2. Right-click the EPICS Client URL in input of the Create EPICS Client VI and select Create»Constant or Create»Control from the shortcut menu. In the constant or control, specify the location to create the EPICS Client I/O server.
  3. Add the Add Record VI to the block diagram.
  4. Wire the EPICS Client ref output of the Create EPICS Client VI to the EPICS Client ref in input of the Add Record VI.
  5. Right-click the record name input of the Add Record VI and select Create»Constant or Create»Control from the shortcut menu. In the constant or control, specify the name of the record you want to add to the EPICS Client I/O server.
  6. Add the Add Field VI to the block diagram.
  7. Wire the EPICS Client ref out output of the Add Record VI to the EPICS Client ref in input of the Add Field VI.
  8. Wire the constant or control of the record name input of the Add Record VI to the record name input of the Add Field VI.
  9. Right-click the field name input of the Add Field VI and select Create»Constant or Create»Control from the shortcut menu. In the constant or control, specify the name of the field you want to add to the EPICS Client I/O server.
  10. (Optional) Right-click the access type input of the Add Field VI and select Create»Constant or Create»Control from the shortcut menu. In the constant or control, select the access type for the field.
  11. (Optional) Right-click the data type input of the Add Field VI and select Create»Constant or Create»Control from the shortcut menu. In the constant or control, select the data type for the field.
  12. Add the Deploy EPICS Client VI to the block diagram.
  13. Wire the EPICS Client ref out output of the Add Field VI to the EPICS Client ref in input of the Deploy EPICS Client VI.
  14. Run this VI to create and deploy the EPICS Client I/O server and to subscribe to the process variables on the EPICS network.

Refer to the EPICS Client API.vi in the labview\examples\comm\EPICS\EPICS Client API\EPICS Client API.lvproj for an example of using the EPICS Client I/O server programmatically.