Additional User Options and Settings
TTL Shutdown Polarity
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 to the power supply without shutting down the power supply. With the Ethernet/RS-232 Interface installed, TTL shutdown is activated by a TTL signal to Pin 1 of the user lines connector on the interface subplate. The shutdown user line uses a 0-5Vdc TTL input with a high signal range of 2.2-5.0Vdc. The current range of the shutdown line is 1-10mA. See Figure 2-6, “User Lines Signal Connector Circuit Block Diagram” on page 2–27for a schematic of the user lines connector containing the shutdown user line.
You can select the logic level of the TTL input by changing the J93 connector on the Ethernet/RS-232 Interface PCB. Table 2-13shows the TTL signal levels for the J93 jumper settings. See Figure 2-3for the location of the J93 jumper on the printed circuit board. You will need to remove the cover to change any jumpers. See “Changing Internal Jumpers” on page 2–8.
Table 2-13Jumper Settings for TTL Shutdown Circuit Logic
PinPCB2Jumperto Pin 3 (default)J93PositionTTLHIGHSignalLevelSupplyOFF OutputCondition
LOWON
Pin 1 to Pin 2 | HIGH | ON |
| LOW | OFF |
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