Mallinckrodt NELLCOR NPB-4000, Service Manual

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Section 3: Performance Verification
3-16
14. Verify that blood pressure values are reasonable for subject.
3.3.4.6.2 Serial Interface Test
Perform the following procedure to test the serial port voltages. The test is
qualitative and will only verify that the serial interface port is powered correctly,
and that the “nurse call” signal is operational. The serial connector is a male
DB-9, located on the monitor’s rear panel, identified with the RS-232 symbol.
1. Set up DMM with function set to “VDC” at a range of 10 volts.
2. Connect DMM negative lead to RS-232 connector pin 5 (GND), or shell of
connector.
3. Connect DMM positive lead to the following pins, in turn, and verify
voltage values listed in Table 3-3.
Note: Voltage for pin 9 will be that listed for the “no alarm” condition.
Table 3-3: Serial Port Voltages
Measurement (V)
Pin Signal Min Type Max
1 not used -0.4 0.0 0.4
2 RXD <<< -0.4 0.0 0.4
3 TXD >>> -5.0 -9.0 -15.0
4 DTR >>> -5.0 -9.0 -15.0
5 GND -0.4 0.0 0.4
6 DSR <<< -0.4 0.0 0.4
7 RTS >>> -5.0 -9.0 -15.0
8 CTS <<< -0.4 0.0 0.4
9 Alarm Out >>>
(no alarm) -5.0 -9.0 -15.0
9 Alarm Out >>>
(alarm underway) 5.0 9.0 15.0
4. Connect Nellcor SRC-2 pulse oximeter tester to monitor via EC-8 sensor
extension cable.
5. Set SRC-2 switches as follows:
SWITCH POSITION
RATE 38
LIGHT LOW
MODULATION LOW
RCAL/MODE RCAL 63/LOC