JMRI: Fast Clock - LocoNet Capability
Author: Bob Jacobsen
Keywords: JMRI help Setup LocoNet Fast Clock

# JMRI Fast Clocks - LocoNet Capability

A Digitrax LocoNet can contain it's own fast clock, driven by the DCS100, DCS200, or DCS50 command stations. A separate LocoNet fast clock is available from Logic Rail Technologies. JMRI can work with any of these, or with any clock that uses the standard Digitrax method to control fast clocks.

This page discusses how JMRI can either use or control the LocoNet fast clock.

## Controlling the LocoNet clock

The "Clock Monitor" tool in the "LocoNet" menu provides a convenient way to:

- Read the current contents of the LocoNet fast clock
- Set the date and time
- Set the rate. Note that you can't explicitly pause a LocoNet clock, but you can stop it by setting the rate to zero.

If you are using a DCS100 or DCS200 command station to create your LocoNet fast clock, you may have noticed that it doesn't keep particularly good time. If you select the "Correct LocoNet Fast Clock Master", JMRI will adjust the rate of the LocoNet clock so that it keeps better time.

## Using the LocoNet clock

The recommended settings for running with LocoNet Fast Clock is: set Time Source to Internal Computer Clock, and check both the Synchronize... and Correct... options. However you can try other settings. If you use the internal computer clock as the time source, you will not be able to change the fast clock rate or the fast clock time from a throttle.

You can also have JMRI use the LocoNet clock for it's own, internal timebase. This keeps the clocks that JMRI displays on the screen synchronized with the LocoNet clock, hence the displays on DT400 throttles, etc.

To do this, select the "LocoNet Fast Clock sets Internal Clock" option on the LocoNet clock monitor window. Note that you should do this before opening the clock windows so that when you open the clock windows they connect to the correct timebase.

If you use a Logic Rail Technologies fast clock, it should be set up as a slave clock, not as a master. You may notice that the Logic Rail Technologies fast clock lags behind by one fast clock minute. Be assured that the correct commands are being sent by JMRI. This lag, if present, is just an artifact of the Logic Rail clock's internal programming.