QSI Keepalive

This page under construction

This subject has come up before, so I guess it is time to address it.

One of the Titan pinout diagrams shows a LENZ keepalive connected, and it is the 3 terminal type. 

Most 3 terminal ones are connections to the keepalive capacitor (with or without charge current limiting resistor and requisite discharge bypass diode) and 1 line to "enable" the keepalive.

(more specific data on various keepalives will follow)

How to connect:

Start the the LS Titan drawing:

You will see that at the bottom, there is a Lenz Power 3, with the plus and minus to J19 and J20... these connections are to C32, which is a 220 mfd 5v cap (the other 2 electrolytic caps are 35v (rectified track power), and 6.3v (must be filtering before microprocessor 5v power supply)

So, right off the bat, it seems that the motors will not be run with the keepalive. A guess on audio, might work, but the amps should be running from a higher voltage supply to get the claimed wattage.

The 5v lamps might work, not sure if the 5v pin on the Titan is this same 5v.

The keepalive control pin is on J2-11, which is port 10 on the LS Titan  (on the titan U HO decoder, the documentation says defaults to light port 10 also)

so now, the next part of the investigation is reading out what FEATURE ID the default firmware has on port 10

This should be CV 115.PI.SI, and reading all 115 CV's, look for the one that is pointing to port 10, in the LS case, I found this was step lights.

Does not seem to make sense yet... but also Colin S found that there is a CV (which I had not investigated) that has a bit for enabling a keepalive: CV56.0, bit 6 (section 5.8.1) and apparently only available on Q3 FX-U....  but the diagram above from QSI shows a large scale titan...

So, time to experiment on port 10.. may want to set some of the DCC timeout CV's (how long the Titan waits for a DCC signal.)

Look at CV58.10.x,  this is a 2 byte value of stopping distance in scale feet, up to 65,535... so that might also need to be set to make sure the loss of DCC does not make it stop immediately. The default value is zero..