Playing trends

One of the most powerful features of the software is the play trend feature. This feature allows you to take data gathered from your process, and see what would happen if you change your ladder logic or other address values.

The play trend feature "feeds" data to the software from .DBF files, replaying the processor's actions in response to the data. You can then monitor your ladder logic, looking for the effects of your changes.

Caution: While the software's play trend feature is useful for examining scenarios involving changes to ladder logic programs, you must not rely solely on your findings from the software to make changes to your process. RSLogix Emulate does not exactly simulate all the functions of a processor. The software does not run at the same speed as your processor, has differences in floating point calculations, and other differences that make it imperative that you carefully consider any changes you make to your process based on findings from a simulation.

Once it's set up, the trend player is as simple to operate as a tape player.

Setting up the trend player

Here's how to set up the trend player feature of RSLogix Emulate:

1. Obtain a .DBF format file from your process.
2. In RSLogix Emulate, load the project into which you want to play a trend.
3. In RSLogix Emulate, click Ladder > Play Trend. RSLogix Emulate displays the trend player dialog.
4. You need to tell RSLogix Emulate where the .DBF file is, and other parameters for your simulation. To do this, click the Setup button. RSLogix Emulate displays the trend player setup dialog.
5. Click the Open button. RSLogix Emulate opens a file selection dialog, allowing you to select a .DBF file to use in the simulation. Select the file you wish to use, and click the OK button.
6. If you like, you can set up the trend player to start and stop at any record number you like. To do this, type record numbers in the Start Play At and Stop Play At fields. By default, the trend player starts at record 0 (the first record) and ends at the last record in the .DBF file.
7. You can adjust the rate at which the trend player feeds data to RSLogix Emulate by moving the Playback slider bar. Moving the slider to the right increases the rate, and moving it to the left decreases the rate.

Note The rate at which RSLogix Emulate performs depends on several factors, including: CPU speed, number of applications running, and memory in your computer.

Assigning addresses in the trend player

If your .DBF file does not contain address information, you must assign addresses to the .DBF file records for the trend player to work.

To assign addresses:

1. In RSLogix Emulate, open the ladder logic project into which you want to play data.
2. Set up the trend player with the .DBF file containing the data you want to play into the project. .
3. From the trend player setup dialog, click the Address button. The software displays the Edit Trend Item Addresses dialog.
4. Click the first address you want to change, and click the Edit button. The address appears in the Assigned Address field at the bottom of the dialog.
5. Type the new address in the Assigned Address field, and click the Save button.
6. Repeat steps 4 and 5 for the remaining addresses you want to redefine.

Trend player controls

The trend player tells you the record number currently being played, and the time stamp on the record (from the .DBF file).

Starting the playback

To start a playback, click the start/restart playback button. The playback will run until the trend player runs out of records in the .DBF file, or until you stop or pause the playback.

Stopping the playback

To stop the playback, click the stop playback button. This stops playback and "rewinds" the trend player back to the first record in the .DBF file. To stop momentarily, click the pause playback button.

Pausing the playback

To pause the playback, click the pause playback button. This stops the playback, and leaves the trend player ready to resume playback at the .DBF file record where you paused it. To resume playback, click the start/restart playback button.

Moving through the .DBF File

You can "rewind" and "fast forward" through the .DBF file by clicking the reverse one record and forward one record buttons. Each click of these buttons moves the trend player back or forward one record in the .DBF file.