RKI Instruments SC-04 User manual

www.rkiinstruments.com
SC-04
Operator’s Manual
Part Number: 71-0548
Revision: P6
Released: 12/23/21

2 • SC-04
WARNING
Read and understand this instruction manual before operating instrument. Improper use of the
gas monitor could result in bodily harm or death.
Maintenance of the gas monitor is essential for proper operation and correct readings.
Bump test the instrument before each day’s use with a known concentration of the target gas.
A bump test can be done in User Mode’s BUMP item or by applying gas in Measuring Mode.
The instrument does not need to be calibrated unless it does not pass the User Mode bump test
or does not respond appropriately, as defined by the user, in Measuring Mode. For more
information about bump test and calibration requirements, see IEC 60079-29-2.

SC-04 • 3
Table of Contents
Chapter 1: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
About the SC-04 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
About this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Chapter 2: Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Instrument Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
LCD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Control Buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Alarm LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Buzzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Vibrator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Infrared Communications Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Standard Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Alligator Clip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Optional Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Watch Band . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Calibration Cup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
IrDA/USB Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Chapter 3: Measuring Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Turning On the SC-04 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Performing a Demand Zero . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Turning Off the SC-04 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Measuring Mode Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Monitoring an Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Alarm Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Responding to Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Data Logging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Chapter 4: Display Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Tips for Using Display Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Peak Screen (PEAK). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
STEL Screen (STEL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
TWA Screen (TWA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

4 • SC-04
User ID Screen (USER ID). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Station ID Screen (STN ID) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Last Successful Calibration Date (CAL.DATA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Last Successful Bump Test Screen (BP.DATA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Date/Time Screen (DATE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Temperature Screen (TEMP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Alarm Points Screen (ALARM--P) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Adjusting the Buzzer Volume (BUZZ.VOL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Chapter 5: User Mode and Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Entering User Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Tips for Using User Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Performing a Bump Test (BUMP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Performing a Calibration (GAS CAL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Setting Calibration Parameters (CAL SET) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Setting Bump Test Parameters (BUMP.SET) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Alarm Settings (ALARM--P) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Updating the Lunch Break Setting (LUNCH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Setting the Confirmation Beep and Non-Compliance Indicator (BEEP) . . . . . . . . . . . . . 57
Updating the Backlight Time (BL TIME). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Turning the Key Tone On/Off (KEY.TONE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Display Mode Items (DISP.SET) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Zero Suppression (ZERO.SUP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Zero Follower (ZERO.FLW) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Turning Easy Calibration On/Off (E-CAL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Setting the Date/Time (DATE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Turning the Password On/Off (PASS-W) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Viewing the ROM/SUM (ROM/SUM). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Entering Measuring Mode (START) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Chapter 6: Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Replacing the Batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Replacing the Sensor Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Replacing the Hydrophobic Filter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Replacing the Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Chapter 7: General Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Appendix A: Maintenance Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Entering Maintenance Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Tips for Using Maintenance Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Performing a Calibration (GAS CAL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Performing a Gas Test (GAS.TEST). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Sensor/Battery Replacement Date (SEN.DATE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

SC-04 • 5
Performing a Bump Test (BUMP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Setting Alarms to Latching or Self-Resetting (LATCH) . . . . . . . . . . . . . . . . . . . . . . . . . 80
Turning the Demand Zero Function On/Off (D.ZERO) . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Turning the Auto Zero Function On/Off (A.ZERO). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Turning the ID Display Function On/Off (ID DISP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Turning the Zero Suppression On/Off (ZERO.SUP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Turning the Zero Follower On/Off (ZERO.FLW) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
User Mode Zero Suppression (ZSUP.DSP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
User Mode Zero Follower (ZFLW.DSP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Cylinder Setting (CYL.DISP). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Setting the Date/Time (DATE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Turning the Password On/Off (PASS-W) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Viewing the ROM/SUM (ROM/SUM). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Performing a Default (M.DEF). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Entering Measuring Mode (START) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Appendix B: Gas Select Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Entering Gas Select Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Tips for Using Gas Select Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Saving the Alarm Points (SAVE-AP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Turning the Calibration Max Span On/Off (MAX.SPAN) . . . . . . . . . . . . . . . . . . . . . . . . 88
Stealth and Vibrator Settings (STEALTH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Exiting Gas Select Mode (START). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Appendix C: Interference Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
ESR-A13D-HCN, HCN Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
ESR-A13D-NO2, NO2Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
ESR-A13D-PH3, PH3Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
ESR-A13D-SO2, SO2Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
ESR-B134-NH3, NH3Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
WARNING: Understand manual before operating. This is an intrinsically safe product.
Substitution of components may impair intrinsic safety. To prevent ignition
of a hazardous atmosphere, batteries must only be changed or charged in
an area known to be nonhazardous. Not tested in oxygen enriched
atmospheres (above 21%).
AVERTISSEMENT:Comprendre le manuel avant de l'utiliser. Ceci est un produit
intrinsèquement sûr. La substitution de composants peut nuire à la sécurité
intrinsèque. Pour éviter l'inflammation d'une atmosphère dangereuse, les
batteries ne doivent être remplacées ou chargées que dans une zone non
dangereuse. Non testé dans des atmosphères enrichies en oxygène (plus de
21%).

6 • Chapter 1: Introduction SC-04
Chapter 1: Introduction
Overview
This chapter briefly describes the SC-04 gas monitor. This chapter also describes the
SC-04 Operator’s Manual (this document). Table 2 at the end of this chapter lists the
specifications for the SC-04.
About the SC-04
Using an advanced detection system, the SC-04 personal gas monitor detects the presence of
super toxic gases like HCN, PH3, and SO2. The SC-04’s compact size and easy-to-use design
make it ideally suited for a wide range of applications, including sewage treatment plants,
utility manholes, tunnels, hazardous waste sites, power stations, petrochemical refineries,
mines, paper mills, drilling rigs, and fire fighting stations. The SC-04 offers a full range of
features, including:
• Liquid crystal display (LCD) for complete and understandable information at a glance
• Ultrabright alarm LED
• Distinctive audible/vibrating alarms for dangerous gas conditions and audible alarms for
unit malfunction
• Microprocessor control for reliability, ease of use, and advanced capabilities
• Data logging functions
• Alarm trend data
• STEL, TWA, and over range alarms
• Peak reading
• Built-in time function
• Lunch break feature
• QPS “C/US” classification for Class I, Division I, Groups A, B, C, and D hazardous
atmospheres
WARNING: The SC-04 detects elevated levels of super toxic gases which can be
dangerous or life threatening. When using the SC-04, you must follow the
instructions and warnings in this manual to assure proper and safe
operation of the unit and to minimize the risk of personal injury. Be sure to
maintain and periodically calibrate the SC-04 as described in this manual.
AVERTISSEMENT:Le SC-04 détecte les niveaux élevés de gaz super toxiques qui peuvent
être dangereux ou mettre la vie en danger. Lorsque vous utilisez le SC-04,
vous devez suivre les instructions et les avertissements de ce manuel pour
assurer un fonctionnement correct et en toute sécurité de l'appareil et pour
réduire les risques de blessures. Assurez-vous de maintenir et d’étalonner
périodiquement le SC-04 comme décrit dans ce manuel.

SC-04 Chapter 1: Introduction • 7
Specifications
Table 1: Standard Sensor Specifications/Alarm Points
Table 2: SC-04 Specifications
Ammonia
(NH3)
Chlorine
(Cl2)
Hydrogen
Cyanide
(HCN)
Nitrogen
Dioxide
(NO2)
Phosphine
(PH3)
Sulfur
Dioxide
(SO2)
Detection Range 0 - 400.0 ppm 0 - 20.00
ppm
0 - 30.0
ppm
0 - 20.00
ppm
0 - 20.00
ppm
0 - 100.00
ppm
Lowest Detectable
Limit (LDL)
4.0 ppm 0.10 ppm 1.0 ppm 0.30 ppm 0.02 ppm 0.20 ppm
Reading Increment 0.5 ppm 0.05 ppm 0.1 ppm 0.05 ppm 0.01 ppm 0.05 ppm
Warning Setpoint 25 ppm 1.00 ppm 5.0 ppm 2.00 ppm 0.30 ppm 2.00 ppm
Alarm Setpoint 35 ppm 2.00 ppm 10.0 ppm 4.00 ppm 0.60 ppm 5.00 ppm
Alarm H Setpoint 300 ppm 10.00 ppm 30.0 ppm 20.00 ppm 0.60 ppm 100.00 ppm
STEL Setpoint 35 ppm 1 ppm 10.0 ppm 1.00 ppm 1.00 ppm 5.00 ppm
TWA Setpoint 25 ppm 0.5 ppm 4.7 ppm 0.50 ppm 0.30 ppm 2.00 ppm
Sampling
Method
Diffusion
Response Time T90 Within 10 Seconds
Display Graphics LCD Display
Operating
Temperature
& Humidity
Continuous environment: -20°C to 50°C/10 to 90% RH
Temporary environment (up to 15 minutes): -40°C to 60°C/0 to 95% RH
Indication
Accuracy
± 10% of reading or ± 5% of full scale (whichever is greater)
Safety/
Regulatory
• ATEX: Certificate Number DEKRA 19ATEX0097
II 1G Ex ia IIC T4 Ga (with alkaline batteries)
II 1G Ex ia IIC T3, Ga (with Ni-MH batteries)
• IECEx: Certificate Number IECEx DEK 19.0059
Ex ia IIC T4 Ga (with alkaline batteries)
Ex ia IIC T3 Ga (with Ni-MH batteries)
• QPS classified, “C/US”, as Intrinsically Safe. Exia. Class I, Groups A, B, C, & D.
Instrument
Power
Information
• Operating Voltage: 3.0V
• Operating Current: 1.0 mA
• Operating Power: 3.0 mW
Power Supply 2 AAA alkaline batteries; 1.5V, 1.175 AH (Duracell MN2400 or PC2400)
OR
2 AAA Ni-MH batteries; 1.2V, 800 mAH (Panasonic Eneloop BK-4MCC)

8 • Chapter 1: Introduction SC-04
About this Manual
The SC-04 Operator’s Manual uses the following conventions for notes, cautions, and
warnings.
NOTE: Describes additional or critical information.
CAUTION: Describes potential damage to equipment.
WARNING: Describes potential danger that can result in injury or death.
Continuous
Operating
Hours
@ 25 °C
Alkaline Batteries: 3,000 hours in Measuring Mode (Non Alarm Operation, Fully Charged)
Ni-MH Batteries: 2,000 hours in Measuring Mode (Non Alarm Operation, Fully Charged)
Case High-impact Plastic, RF Shielded, Dust and Weather Proof (IP67)
Standard
Accessories
• Alligator clip
• Rubber boot
Optional
Accessories
• Belt clip
• Calibration cup
• Datalogging and Setup Programs (Windows®7, 8, and 10), available at
www.rkiinstruments.com/04series
• IrDA/USB Cable for connecting to a computer when using the Datalogging and Setup
Programs (not needed if computer has an infrared port)
Dimensions
and Weight
Approximately 67(H) x 54(W) x 24(D) mm (2.6”H x 2.1”W x 0.9”D)
Approximately 93 g (3.3 oz.)

SC-04 Chapter 2: Description • 9
Chapter 2: Description
Overview
This chapter describes the SC-04 instrument and its accessories.
Instrument Description
Case
The SC-04’s sturdy, high-impact plastic case is radio frequency (RF) resistant and is suitable
for use in many environmental conditions, indoors and out. The case is dust proof and water
resistant. A clear plastic window is located on the front of the case for viewing the LCD. The
sensor retainer is located on the right side of the case and allows access to the filters and
sensor. A feature in the lower left corner of the rear case is used to install the optional wrist
strap.
LCD
A digital LCD (liquid crystal display) is visible through a clear plastic window in the top case.
The LCD shows the gas reading. The LCD also shows information for each of the SC-04’s
operating modes.
Battery Cover Screw
Battery Cover
AIR
SO2
LCD
Buzzer Opening
IrDA Port
Control Buttons Wrist Strap
Connection
POWER
MODE
Diffusion Port
Alarm LED
Figure 1: Component Location

10 • Chapter 2: Description SC-04
Control Buttons
Two control buttons, AIR and POWER MODE, are located below the LCD.
Alarm LED
The alarm LED above the sensor and buzzer openings alerts you to gas, low battery, and
failure alarms.
Buzzer
One solid-state electronic buzzer is located inside the case. Sound exits the case through a
hole in the upper left corner of the front case. The buzzer sounds for gas alarms, malfunctions,
and low battery voltage. It also provides feedback for button presses and while in Display,
User, Maintenance, or Gas Select Mode.
Vibrator
A vibrating motor inside the SC-04 case vibrates for gas alarms and unit malfunctions.
NOTE: If STEALTH is set to ON, the vibrator only functions when VIB in the STEALTH
Gas Select Mode item is set to ON (see pg.89).
Sensor
The sensor is an electrochemical cell that consists of two precious metal electrodes in a dilute
acid electrolyte. A gas permeable membrane covers the sensor face and allows gas to diffuse
into the electrolyte. The gas reacts in the sensor and produces a current proportional to the
concentration of the target gas. The SC-04’s circuitry amplifies the current, converts the
current to a gas concentration, and displays the concentration on the LCD.
Each target gas has its own sensor.
Table 3: SC-04 Control Button Functions
Button Function(s)
AIR • turns on LCD backlight
• resets alarm condition if LATCH is set to ON in Maintenance Mode
• enters User Mode, Maintenance Mode, and Gas Select Mode when used
with POWER MODE
• activates the demand zero function (adjusts the SC-04’s fresh air reading)
• changes the value of a parameter available for adjustment
• scrolls through parameter options
POWER MODE • turns the SC-04 on and off
• turns on LCD backlight
• enters and scrolls through Display Mode
• enters instructions into the SC-04’s microprocessor
• resets alarm condition if LATCH is set to ON in Maintenance Mode
• enters User Mode, Maintenance Mode, and Gas Select Mode when used
with AIR