804 Quickstart Guide
User Guide
Quick Setup Guide
Model 80
Met One Instruments 804 Quickstart Guide
Serial Commands
Protocol Summary
- Baud Rate: 38,400 Baud, 8 Data bits, No Parity, 1 Stop Bit
- Case Sensitivity: Commands (CMD) are UPPER or lower case
- Termination: Commands are terminated with a carriage return <CR>
- View Settings: CMD <CR>
- Change Settings: CMD <SPACE> <Value> <CR>
| CMD | Type | Description |
|---|---|---|
| ?, H | Help | View the help menu |
| 1 | Settings | View the settings |
| 2 | All data | Returns all available records. |
| 3 | New data | Returns all records since last ‘2’ or ‘3’ command. |
| 4 | Last data | Returns the last record or last n records (n = <Value>) |
| D | Date | Change date. Date format is MM/DD/YY |
| T | Time | Change time. Time format is HH:MM:SS |
| C | Clear data | Displays a prompt for clearing the stored unit data. |
| S | Start | Start a sample |
| E | End | Ends a sample (abort the sample, no data record) |
| ST | Sample time | View / change the sample time. Range: 3 to 60 seconds. |
| ID | Location | View / change the location number. Range: 1 to 999. |
| CS w x y z | Channel Sizes | View / change channel sizes where w=Size1, x=Size2, y=Size3 and z=Size4. Values: 1=0.3, 2=0.5, 3=0.7, 4=1.0, 5=2.5, 6=5.0, 7=10 |
| SM | Sample mode | View / change sample mode. (0=Manual, 1=Continuous) |
| CU | Count units | View / change count units. Values: 0=CF, 1=/L, 2=TC |
| OP | Op Status | Replies OP x, where x is “S” (Stopped) or “R” (Running) |
| RV | Revision | View Software Revision |
| DT | Date Time | View / change date and time. (DD-MM-YY HH:MM:SS) |
Settings Table
| Function | Description |
|---|---|
| LOCATION NUMBER | Range = 1 – 999 |
| SIZES | Channel sizes. Select from list of 7 standard sizes (0.3, 0.5, 0.7, 1.0, 2.5, 5.0, 10 um) |
| FAVORITES | Select favorite display sizes |
| SAMPLE MODE | Manual or Continuous |
| COUNT UNITS | Total Count (TC), Particles / cubic foot (CF), particles / L (/L) |
| HISTORY | Display previous samples |
| SAMPLE TIME | Range = 1 – 60 seconds |
| TIME | Display / enter time |
| DATE | Display / enter date |
| MEMORY | Display percent of memory available or clear all samples |
| PASSWORD | Enter password to lock settings |
| ABOUT | Model Number and firmware version |
Factory Default Settings
| Parameter | Value |
|---|---|
| Sizes | 0.3, 0.5, 5.0, 10 um |
| Favorite 1 | 0.3 mm |
| Favorite 2 | OFF |
| Sample Location | 1 |
| Sample Mode | Manual |
| Sample Time | 60 seconds |
| Count Units | CF |
Met One Instruments Inc.
200 N.E Greenfield Road Grants Pass, OR 97526
Phone: 541-471-7111
Web: www.metone.com
804-9801 Rev. C
Documents / Resources
 | 804 Quickstart Guide |
References
- Met One - Precision Air Quality Monitoring Instrumentswww.metone.com
- User Manualmanual.tools
Published: October 22, 2026
Updated: October 23, 2026