Digitrax PM74 Manual - Página 4

Procurar online ou descarregar pdf Manual para Fonte de alimentação Digitrax PM74. Digitrax PM74 8 páginas. Power manager with occupancy and transponding detection for 4 sub-districts

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briefly and is being detected, the booster track voltage becomes chaotic and

the DCC packets are mutilated.

For reliable detection performance best practice is to not use Analog Mode/

Address 00 zero-stretching.

If OPSW41 is CLOSED (C) the status and optional LT5 leds will now report

relay state, not the Occupancy and Transponding state displayed when

OPSW41= THROWN (T). For short circuit configured DS's the correspond-

ing leds will light as the DS relay actuates to cut off a faulted DS. For a

Auto-reverse DS the, e.g. example L2, led will flip lit to unlit as DS2 polarity

changes. LocoNet messages are unaffected by this OPSW.

3.0 Auto-reverse DS connection:

To set up an Auto-reverse DS section like example DS2 rails of Figure 1:

Set OPSW2 = C to configure DS2 for auto-reverse. See section 5.0 for option

switch setup.

The DS2 4-pin screw terminal block must be wired with; (a) 2AC connected

to 2BO and then to e.g. the DS2 RA rail, and (b) 2AO connected to 2BC and

then to e.g. DS2 RB rail. On a fault the DS2 relay operates to reverse the

loop polarity and the actual DS2 RA/RB connections reverse DCC polarity

The Figure 1 PM74 DS2 section wiring, and option switch are now config-

ured for Auto-reverse action. In this example the rails between double gap

portals G1 and G2 are configured as a Wye or reverse loop section. This has

to have an entry portal G1 or G2 DCC polarity-matched for a train to cross

that gap.

The Auto-reverse action on DS2 fault detection will flip the polarity of DS2

rails, which fixes the gap that has the problem. For a reverse loop, fixing

a first gap portal means the other portal gap will become polarity mis-

matched.

4.0 Alternate Short Circuit protection:

For a slightly simplified DS short-circuit wiring option, DS3 and DS4 examples in

Figure 1 are shown each wired with only a single 3AC or 4AC connection.

Follow the Figure 1 wiring example for DS3 and DS4.

Since we are using the 3AC and 4AC 4-pin terminals only, the connected DS3

and DS4 sections must have their RB rail current return connected back to

the FB feeder. This is because the G3 and G4 gaps are not double and only

isolate and protect the DS3/4 RA rails from over current faults.

Since DS3 and DS4 RB currents are not being monitored any faults on these

RB rails of are not protected by the PM74, and so rely solely on the Booster

fault protection capability. Now RB faults in DS3 and DS4 disrupt the DCC

power to all tracks on the booster.

Excluding the RB current in a DS also lowers the; fault current, and both

Transponding and Occupancy sensitivity, so this wiring method is not the

best choice.

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