M9B-HFS INTERFACE
INSPECTION AND CONFIGURATION
Release 1.0 (97/10)
2-9
2.7.2
TTL Shutdown
You can use the Shutdown function to disable or enable the supply's output. Disabling the supply using TTL
shutdown allows you to make adjustments to the load or the power supply without shutting down the power
supply. With the M9B-HFS interface installed, TTL shutdown is activated by a TTL signal to Pin 1 of the J7
connector on the interface subplate.
You can select the logic level of the TTL input by changing the J92 connector on the M9B-HFS PCB. Table 2.7-2
shows the TTL signal levels for the J92 jumper settings. See
Figure 2.7-1
for the location of the J92 jumper on the
printed circuit board.
Table 2.7-2 Switch Settings for TTL Shutdown Circuit Logic
PCB Jumper J92 Position
TTL Signal Level
Supply Output Condition
Pin 2 to Pin 3
HIGH
LOW
OFF
ON
Pin 1 to Pin 2
HIGH
LOW
ON
OFF
2.7.3
Local Mode Disable
You can disable local control of the power supply by removing jumper J104 on the option card PCB. We
recommend that you remove jumper J104 only if you never plan to control the power supply from the front panel.
Otherwise, the software commands and the front panel return to local (LOCAL) button will offer you greater
flexibility in controlling your supply.
When the Local Mode Disable jumper J104 is closed, you can select between operating the power supply in
either local mode or remote mode by using the software commands and the front panel return to local (LOCAL)
button. With jumper J104 open, you can only operate the power supply in remote mode. Opening the J104 jumper
disables the front panel LOCAL button and the front panel voltage and current limit potentiometers. You cannot
return to local mode using software commands without closing jumper J104. Table 2.7-3 gives a quick reference
to how the jumper affects the operating state of the power supply. Figure 2.7-1 shows the position of jumper J104
on the M9B-HFS PCB.
Table 2.7-3 Local Mode Disable Jumper J104 Selection
Jumper J104 Position
Operating State
Closed
Remote or Local Control of Power Supply
Open
Software Control Only
Note:
The location of over voltage protection control is dependent on the positions of jumper J104 and OVP
control jumper J66. Table 2.7-1 shows how the jumper positions affect the location of OVP control.