Fluke Biomedical 956A-201-M2 - Manual (Page 63)

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Table 3-17. Option Jumper Select Read Functions
Data Bit Function
D0 Serial data from E 2 PROM
D1 Anti-Jam
D2 (Not used)
D3 JP3-5 (IN) Inhibit alarms during check source operation
(OUT) Alarms active during check source operation
D4 JP3-4 (IN) Fails in five minutes with no counts
(OUT) Does not fail
D5 JP3-3 (OUT) Auto alarm acknowledge, after counts return to
normal
(IN) Manual Reset (factory setting)
D6 JP3-2 IN/IN, Fixed 1 second update
D7 JP3-1 IN/OUT, 384 Target Counts, 10% accuracy
OUT/IN, 1537 Target Counts, 5% accuracy
OUT/OUT, 9604 Target Counts, 2% accuracy
JP3 jumper IN MPU reads a low (0)
JP3 jumper OUT MPU reads a high (1)
Switch Inputs
Octal inverting buffer U62 functions as an interface to provide the status of the front panel control switches
to the internal data bus and MPU. U62 responds to address 4000 and / SWITCH INTERFACE. The
switch input bit assignments are listed in table 3-18.
Table 3-18. Switch Input Bit Assignments (U62)
Data Bit Function
D0 Alarm Acknowledge
D1 Check Source
D2 (Spare, Input 2)
D3 (Spare, Input 1)
D4 Rate-of-Rise (not used)
D5 Warn Alarm
D6 High Alarm
D7 High Voltage (not used)
When a switch is pressed, the appropriate input to U62 is pulled low. When U62 is read by the MPU, a
high (1) is available on the data bus. When no switches have been pressed, all outputs (U62) will be low
when read. U63A and B are D Type Flip-Flops that latch switch data from the check source and alarm
acknowledge switches. The MPU controls the clear switch latch signal to reset U63A and B. The circuit
comprised by S1, D1, and R11 is a remote alarm acknowledge. R11 is selected to allow a 20 mA signal to
flow through the S1 infrared diode when a given voltage is present on the J9 remote acknowledge input.
When this voltage is present, the S1 infrared diode is forward biased, causing the S1 phototransistor to
conduct. This effectively forces a low (0) to U63-10, setting the alarm acknowledge bit.
Option Board Bus
The option board bus is available on connector J3. All address, data, and control signals are provided to
allow various digital/analog circuit boards to directly interface to the main circuit board. Decoded signals
for asynchronous communications interface adapter option, and the general-purpose interface bus option
are available on the option board interface connector.