Appendix B: Motor-Power Board Connectors
which output controls the computer's DC:DC voltage converter. Designed to provide for crash-less shutdown of the computer in the event of a power brownout or for unattended shutdowns, if Vpp drops below 10 VDC, the comparator automatically initiates a two-minute delay before computer power (not system-wide) shutdown.
Similarly, when the computer power is manually switched OFF, the comparator is grounded (below 10 VDC, of course) and the same two minute-delayed shutdown occurs.
In all cases, power shutdown, but not necessarily computer software shutdown, is canceled if power is restored to above 10 VDC, either by connecting a battery charger or by hot-swapping the batteries.
With older Motor-Power systems, you may disable the two-minute delay circuitry (switched or low-voltage shutdown immediate) by moving the jumpers on both J3 and J6 on the Motor-Power Board to the pins opposite their ON position.
Power-State Logic
A 9-pin DSUB receptacle (P1) on the Motor-Power board provides a logic-level shutdown indicator (DCD pin 1) which state goes low when computer power shutdown is first initiated. The onboard computer may use this line state to initiate software-mediated shutdown, such as provided by genpowerd for RedHat© Linux PCs.
Table 24. Power State 9-pin DSUB receptacle (P1)
1 | 2 | 3 | 4 | | 5 | 6 | | 7 | 8 | 9 |
DCD | nc | nc | pin 6 | nc | pin 4 | nc | nc | Gnd |
| | | | 10- | 20K adj. | | | | |
| | | | across 4 & 6 | | | | |
Computer Power
Table 25. Computer power connector
Acommon 4-conductor, bevel-keyed connector (J5) provides 5 VDC @ 7A power for the onboard computer, and battery power for the optional 12VDC fan.
Pin # | Connection |
1 | Vpp |
2 | Gnd |
3 | Gnd |
4 | 5VDC @ 7A |
