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800961-C
Nov. 2000
区 rr NCKRODT
The handswitch interface connects the remote start handswitch to
the CPU board. +12V is supplied to the handswitch connector, J1.
Four identical isolated inputs are also connected to J1. Two of the
isolated inputs are used for the handswitch and two are spare.
Handswitch Interface
The isolated input circuit consists of a current limiting resistor (RN3)
connected to the LED side of an opto-isolator (U1, U2). The output
of the opto-isolator is pulled high by RN7 and input to inverter U3.
The remote handswitch uses a double action switch to connect
+12V to the isolated inputs. This is done as a safety feature to
eliminate a single fault failure from initiating an injection. The
software has to see both handswitch inputs open and then closed
in order to start an injection.
The handswitch connector pinout is shown in Table 3-4.
Table 3-4, Handswitch Connector Pinout
J5 Pin |
Signal Name
1
Spare in 2
2
+12V
3
Handswitch in 1
4
+12V
5
+12V
6
Chassis GND
7
Handswitch in 2
8
Spare in 1
3-15
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