Model 9843

Model 9843 Specifications

Print Specs

Oxygen Saturation Display Range: 0% to 100% SpO2
Pulse Rate Display Range: 18 to 321 beats per minute (BPM)
CO2 Range: 0 to >75mmHg
CO2 Response Time: 250 ms
Respiration Rate Range: 1 to 60 breaths per minute
Breath Detection Threshold: 5 mmHg
Accuracy – Sensors: Declared accuracy data for compatible sensors can be found in Nonin’s Sensor Accuracy document.
CO2 Accuracy of Bar Graph Thresholds (Arms)*: ±25% of reading (typical)
Measurement Wavelengths and Output Power**::
Red: 660 nanometers @ 0.8 mW maximum average
Infrared: 910 nanometers @ 1.2 mW maximum average

Pulse Quality Indicator: LED, tricolor
Numeric Displays: 3-digit, 7-segment LEDs, tricolor
CO2 Bar Graph: 8-segment bar graph, red
Low Battery Indicator: Dedicated icon, red
Audible Indicator: Miniature speaker

Temperature (Operating):
Pulse Oximeter: 0 °C to +40 °C (32 °F to +104 °F)
Temperature (Storage/Transportation): -40 °C to +70 °C (-40 °F to +158 °F)

Operating: 10% to 95% non-condensing
Storage/Transportation: 10% to 95% non-condensing

Operating: Up to 3,000 meters (10,000 feet)
Hyperbaric Pressure: Up to 4 atmospheres

Power Requirements:
Six 1.5V AA-size alkaline batteries.
90 hours – Pulse Oximeter only.
20 hours – CO2 and Pulse Oximeter.
24 hours – CO2 only.

Dimensions: 8 cm W x 15 cm H x 2.5 cm D (3 in W x 6 in H x 1 in D)
Weight: 310 g (11 oz) (with alkaline batteries)
Classifications per IEC 60601-1 / CAN/CSA-C22.2 No. 601.1 / UL 60601-1:
Type of Protection: Internally powered (on battery power)
Degree of Protection: Type BF-Applied Part
Mode of Operation: Continuous

Enclosure Degree of Ingress Protection: IP32

This device is not made with natural rubber latex.

* ± 1 Arms represents approximately 68% of measurements.
** This information is especially useful for clinicians performing photodynamic therapy.

Model 9843 Troubleshooting

The veterinary CO2 detector is a mainstream device intended to be used for semiquantitative detection of CO2 levels in intubated patients. The CO2 detector main purpose is to be used to initially confirm proper placement of the endotracheal tube and to provide continued confirmation of correct endotracheal tube placement and respiration status. The CO2 portion of the unit is designed to approximately measure the CO2 changes in the patient airway adapter tube, and is not intended to provide the accuracy of a capnometer or capnograph. The CO2 is calculated by assuming the rapid decrease in measured CO2 on the start of an inhalation where a negligible amount of CO2 is present.

This is the baseline for calculating the exhaled CO2. When the patient exhales this is the absorption change due to the increasing amount of CO2 in the light path.


Apnea, oxygen saturation, pulse rate alarms and 18-hour memory.


When turned on this unit should beep 3 times to show the user that the speakers are
functioning. After power-up the advance switch can be pressed to verify speaker
function or change the speaker volume. If the speakers do not work on power-up the unit
needs to be returned for service.


  1. Variable pitch this is the units’ default setting. During variable pitch breath
    beeps, the tone of the breath beeps is indexed to the number of bars illuminated on
    the CO2 display. The more bars lit, the higher the pitch. In this mode the breath
    beeps will sound at inspiration, the falling edge of the CO2 waveform.
  2. Fixed pitch breath beep has a pitch higher than the highest bar graph-indexed
    pitch. In this mode the breath beeps will sound during exhalation, on the
    rising edge of the CO2 waveform.

NO CO2 BARS OR ONLY 3rd and 6th BAR:
During the power-up sequence the CO2 bar graph should rise and fall to show all led’s for the CO2 are working properly. If no sensors are plugged in there should no lights on the display only a flickering LED in the switch panel. When the CO2 sensor is plugged in with no AAT in place the unit will have the 3rd and 6th bar lit. If the bars do not light when the CO2 sensor is plugged in check the serial number of the sensor to verify its age, normally it will be a sensor problem.
When the sensor is plugged with a new AAT the bar graph should register 1 or 2 bars and if they breathe through the AAT the bar graph should rise and fall. If this doesn’t
happen, make sure it’s a NEW AAT.

Since these units are used in surgery make sure the CO2 sensor stays dry, they do not like moisture. Place a wash cloth over the sensor or use a plastic sandwich bag and cut a slit in one end and slide the bag over the sensor, this helps keep the AAT dry.


Batteries will last about 100 hours using only the oximeter portion, if using both oximeter and CO2 battery life is about 15-20 hours.

Frequently Asked Questions

What is included in the 9843 package assembly?

  • 9843 Pulse Oximeter
  • 9843 Manual on CD
  • 9840SA CO2 Sensor
  • 8000AA Pulse Oximeter Sensor
  • 6 AA-Size Alkaline Batteries

How do you know you’re getting an accurate reading?

The tricolor LED display (m) provides a visual indication of the pulse
signal quality, while blinking at the corresponding pulse rate. This display
changes colors to alert you to changes in pulse quality that may affect the
readings: green indicates a good pulse signal, yellow indicates a marginal
pulse signal, and red indicates an inadequate pulse signal. Allow the 9843
to stabilize, observing about 10 seconds of continuous green-colored pulse
quality before relying on the displayed values. It is common for the
displayed values to fluctuate slightly over a period of several seconds. If the
pulse quality display blinks yellow or red, try another finger.

What kind of battery is used in the 9843?

Six AA Alkaline batteries.

How many hours of battery life can I expect?

The 9843 will typically operate for 90 hours continuously between
alkaline battery replacements for pulse oximetry alone, or 20 hours
continuously with both CO2 detection and pulse oximetry operating

How do you access the memory stored in device?

NONIN’s nVISION data management software and 1000MC serial cable
will allow you to connect the 9843 to PC for downloading data and view

What happens to the stored memory after 72 hours have been displayed?

The memory in the device functions as an “endless loop.” When the
memory fills up, the unit begins overwriting the oldest data with the newest.


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