# JMRI: RPS Polling Control

The RPS Polling Control window is where you tell the RPS system which of your locomotives have RPS transmitters installed, and how often to talk to them.

When you open the window, you should see your entire roster of locomotives displayed, one per line.

If a locomotive has a RPS transmitter installed and you'd like the system to track its position, check the box in the "Poll" column.

To control whether the system as a whole is polling, check or uncheck the "Poll" box in the bottom section of the window.

The table has nine columns:

- "Roster Name" - This is the locomotive decoder name from the roster.
- "ID" - The name that RPS uses to refer to this transmitter. By default, it's the same as the roster name, but you can change it if you'd like.
- "Locomotive Address" and "Long" - The DCC address of the decoder. The "Long" box will be checked if this is a "long" ("extended") address.
- "Polled" - Should the RPS system measure this position?
- "Last X", "Last Y", "Last Z" - The most recent measured position for this transmitter.
- "Last Time" - The time the last measurement was taken.

There are three radio buttons that control how polling is done.

Use BSC Poll
  When checked, this uses a "Binary State Command" to poll the RPS system. If your RPS transmitters support this, it is the recommended setting except for with Lenz systems.
Use Direct Poll
  When checked, JMRI sends F2 commands directly on the track. Use this if your RPS transmitters require F2 polls, and you don't have a Lenz DCC system.
Use Throttle Poll
  When checked, JMRI simulates a throttle to send F2 polls. This is currently required for Lenz systems, and not recommended for others.

The interval box controls the number of milliseconds between polls. This should not be set below about 80. If you are polling less than 5 transmitters, set it to 300 or above. This option will eventually be removed in a later JMRI version, when it becomes automatic.

To save the values so they'll be automatically used when the program is next started, click "Store New Default Values".