Home | OPC Servers and iFix Drivers | Universal OPC Server | Custom Work | Contact Info
UOS provides three ways to control polling (reading data); Automatic, On Demand, and Enable/Disable. Each method is described below.
Automatic
Purpose - Used to continuously request data from a device at a specified interval. For example, read the weight every one second.

How to Implement - In the UOS Power Tool, set the Polling Setup, Primary Rate field to the required interval in seconds.

On Demand
Purpose - Used to request data from a device only when the user or logic initiates the request. For example, read weight only when the user presses a button on the screen.

How to Implement - In the UOS Power Tool, assume that you created a DataBlock to read weigh and named it RDW. You also set the Primary Rate field to "Disabled". In the Database Builder create a Digital Output (DO) block with an I/O Address equal to RDW:POLL. Now, every time you write a one (1) to the DO block UOS will read the weight. A one can be written to the DO block using script behind a button on a VIEW screen or by using logic.

Enable/Disable
Purpose - Used to request data from a device at a specified interval for a period of time specified by the user or logic. For example, read the weight every one second for one hour and then stop. Enable/disable should also be used if a device you are polling in Automatic mode has a hardware failure. You can disable polling, which takes the device "off line" until it can be repaired.

How to Implement - In the UOS Power Tool, create a DataBlock to read weigh and name it RDW. You also set the Primary Rate field to the required interval (1 second). In the Database Builder create a Digital Output (DO) block with an I/O Address equal to RDW:ENABLE. Now, every time you write a one (1) to the DO block USD will enable polling (read weight at the specified poll time). Writing a zero (0) to the DO block will stop polling. A one or zero can be written to the DO block using script behind a button on a VIEW screen or by using logic. When the driver is first loaded or restarted, polling is automatically enabled and must be disabled manually.

*Use your browser's BACK button to return to the Profile Data Sheet.

© 2011 Dimension Software, Inc. All Rights Reserved.