To add Modbus client proxy points

Once a client Modbus device is added, you can add proxy points to read and write data. If programming online (and the device shows a status of “{ok}”), you can get statuses and values back immediately, to help determine if point configuration is correct. Use the following procedure:

To create client Modbus proxy points in a device:

1. In the Device Manager, in the Exts column, double-click the Points icon   in the row representing the device you wish to create proxy points.

   This brings up the Modbus Client Point Manager.

2. (Optional) Click the New Folder button to create a new points folder to help organize points, and give it a short name, such as “Hldg1_to_64”, or whatever name works for your application. You can repeat this to make multiple points folders, or simply skip this step to make all proxy points in the root of Points.

   Note that all points folders have their own Modbus Client Point Manager view, just like Points. If making points folders, double-click one to move to its location (and see the point manager).

3. At the location needed (Points root, or a points folder), click the New button.

   The New points dialog appears, in which you select a point “Type,” “Number to Add,” “Starting Address,” and “Data Type” (latter applies only if selecting type: Numeric Point or Numeric Writable).

   For more details, see Modbus client proxy points.

4. Click OK.

   This brings up another New dialog to name the point(s), enter data addresses as well as enter other information, such as point facets and conversion. Default point names use a convention similar to: “<PointType><Address>”, for example: “Numeric Point40012” or “Boolean Writable6”.

   Details on related entries in this step are in Modbus client point ProxyExt properties, and background information is given in the section Modbus Meets NiagaraAX.

5. Click OK to add the proxy point(s) to the Points extension (or to the current points folder), where each shows as a row in the point manager.

   If addressed correctly, each point should have a status of “{ok}” with a polled value displayed.

   • If a point shows a “{fault}” status, check its ProxyExt “Fault Cause” property value, which typically includes a Modbus “exception code” string, such as “Read fault: illegal data address”.

     In such a case, re-check the address in the point against the documented address for the data item.

     For related details, see Exception codes, and sections Data address format in NiagaraAX, and Data address format in NiagaraAX.

   • If a NumericPoint or NumericWritable for a float or long (2-register) value shows a “0” value (or an impossibly large value) instead of an expected value, yet still has an “{ok}” status, verify that the correct “byte order” settings exist for float and long values in the parent device.

     See Modbus Config (client device level) for related details.

6. Continue to add proxy points as needed under the Points extension of each client Modbus device.

   As needed, double-click one or more existing points for the Edit dialog, similar to the New dialog used to create the points. This is commonly done for re-editing items like data addresses, names, or facets.

7. After all needed proxy points have been added under a device, you may wish to configure it for “device polling.” Typically, this improves polling response due to fewer messages to get the same amount of data.

   To configure a client Modbus device for device polling:

   1. In the Nav side bar, expand the Modbus device so you see its Device Poll Config slot (or, open the property sheet of the Modbus device to see this same slot listed with other properties/slots).

   2. Right-click Device Poll Config, and select ActionsLearn Optimum Device Poll Config.

      The necessary Device Poll Config Entry components are automatically added and configured under this container. For more details, see Configuring Device Poll Config.