Operating instructions
Installation SW 5250A•SW 3500A•SW 1750A
2-8 Operation Manual
7 .#%"'!+ #"'/
The DFI connector on the rear panel has both input and output functionality.
The DFI Output Relay indicates a shutdown fault has occurred on the SW. It is a SPST
reed relay with rear panel connections to the normally closed output contacts. When
the SW is operating the relay is energized so that the contacts are open. When a fault
occurs, or if the unit should lose power, the relay closes to indicate a fault has occurred.
The DFI Output Relay will remain latched until the front panel Power switch is cycled.
The DFI Input Signal is used to command the SW to open the Output relay, and close
the DFI relay. It is a TTL-compatible input with a 1 kΩ input impedance, a 10 kΩ pullup
to +5 VDC, and clamping diodes to +5 VDC and ground. A signal with a negative going
edge from +5 VDC to ground will trigger the DFI response.
Refer to Figure 2–3, Item 5.
A
1 DFI RLY COMM —
2 Not Used —
3 DFI IN +
TTL (10 kΩ input impedance)
4 and 5 Not Used —
6 DFI RLY N.O. —
7 Not Used —
8 DFI IN RTN TTL
9 IEEE 488.2 SIGNAL GND
Table 2–4 DFI Connector Pinout