Difference between revisions of "RadioShack 22-812"

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[[File:radioshack_22_812_angle.jpg|thumb|right|Radioshack 22-812]]
{{Infobox multimeter
| image          = [[File:radioshack_22_812_front.png|180px]]
| name            = RadioShack 22-812
| status          = supported
| source_code_dir = serial-dmm
| counts          = 4000
| categories      = CAT II (600V)
| connectivity    = RS232 (standard DB9 connector)
| measurements    = voltage, temperature, current, resistance, capacitance, continuity, diode, logic, frequency, hFE, duty cycle, pulse width
| features        = autorange, data hold, min/max, dBmW (600Ω)
| website        = [https://www.radioshack.com/search/softwareResults.jsp?kw=22-812 radioshack.com]
}}


The Rasioshack 22-812 is a 4000 counts, CAT II handheld digital multimeter with RS-232 connectivity. It is not yet clear if this is the same device as the [http://www.radioshack.com/product/index.jsp?productId=12988573 Radioshack 22-039].
The '''RadioShack 22-812''' is a 4000 counts, CAT II (600V) handheld digital multimeter with RS-232 connectivity.
 
It is no longer sold under this part number, and for a while, it appeared to have been discontinued. RadioShack does sell a visually identical multimeter, the [https://www.radioshack.com/product/index.jsp?productId=12988573 RadioShack 22-039]. It is not yet clear if the 22-039 is the same device as the 22-812.
 
== Hardware ==
 
The microcontroller is an unidentifiable plastic blob.
 
This devices has a standard DB-9 connector at the top, and does not require a special adapter cable. The RS-232 transmitter is optically insulated from the rest of the device. The transmitter uses a separate PCB, integrated into the multimeter's housing. The RS-232 module is powered from the serial port.


== Photos ==
== Photos ==


<gallery>
<gallery>
File:radioshack_22_812_front_crappy.jpg|<small>Device, front</small>
File:radioshack_22_812_front.png|<small>Mugshot</small>
File:radioshack_22_812_angle.jpg|<small>Device, angle</small>
File:radioshack_22_812_angle.jpg|<small>Device, angle</small>
File:radioshack_22_812_interface.jpg|<small>RS-232 connector</small>
File:Radioshack_22_812_nocover_front.jpg|<small>Holster removed, front</small>
File:Radioshack_22_812_nocover_back.jpg|<small>Holster removed, back</small>
File:Radioshack_22_812_batt.jpg|<small>Battery location</small>
File:Radioshack_22_812_inside.jpg|<small>Opened up</small>
File:Radioshack_22_812_pcb_removed.jpg|<small>PCB removed</small>
File:Radioshack_22_812_pcb_front.jpg|<small>PCB, front</small>
File:Radioshack_22_812_pcb_back.jpg|<small>PCB, back</small>
File:Radioshack_22_812_button pcb.jpg|<small> Buttons PCB</small>
File:Radioshack_22_812_transmitter.jpg|<small>RS-232 module</small>
File:Radioshack_22_812_transmitte_module.jpg|<small>RS-232 transmitter</small>
File:Radioshack_22_812_transmitter_top.jpg|<small>RS-232 PCB, top</small>
File:Radioshack_22_812_transmitter_back.jpg|<small>RS-232  PCB, bottom</small>
File:Radioshack_22_812_terminal.jpg|<small>Banana sockets connecting to PCB</small>
File:Radioshack_22_812_fuse holder.jpg|<small>Spare fuse</small>
File:Radioshack_22_812_chip.jpg|<small>Multimeter IC</small>
File:Radioshack_22_812_calibration.jpg|<small>Calibration pots</small>
</gallery>
</gallery>


Line 13: Line 49:


The device periodically sends 9-byte packets at 4800 baud, 8n1.
The device periodically sends 9-byte packets at 4800 baud, 8n1.
The packet includes a mode indicator, payload and checksum. the payload is a 1-1 mapping of the LCD segments.
The packet includes a mode indicator, payload and checksum. The payload is a 1-1 mapping of the LCD segments.
                                Bit
 
Byte   7       6       5       4       3       2       1       0
=== Packet structure ===
0       ---------------------- Mode -----------------------------
 
1       Hz     Ohms   K      M       F       A       V       m
{| border="0" style="font-size: smaller" class="alternategrey sigroktable"
2       u       n       dBm     s       %       hFE     REL     MIN
|-
3       4D     4C     4G     4B     DP3     4E     4F     4A
! style="width: 3em;" | Byte
4       3D     3C     3G     3B     DP2     3E     3F     3A
! style="width: 3em;" | 7
5       2D     2C     2G     2B     DP1     2E     2F     2A
! style="width: 3em;" | 6
6       1D     1C     1G     1B     MAX     1E     1F     1A
! style="width: 3em;" | 5
7       Beep   Diode   Bat     Hold   -       ~       RS232   Auto
! style="width: 3em;" | 4
8       -------------------- Checksum ---------------------------
! style="width: 3em;" | 3
! style="width: 3em;" | 2
! style="width: 3em;" | 1
! style="width: 3em;" | 0
 
|-
| 0
! colspan="8" | Mode
 
|-
| 1
| Hz
| Ohms
| k
| M  
| F
| A
| V
| m
 
|-
| 2
| u
| n
| dBm
| s
| %
| hFE
| REL
| MIN
 
|-
| 3
| 4D
| 4C
| 4G
| 4B
| DP3
| 4E
| 4F
| 4A
 
|-
| 4
| 3D
| 3C
| 3G
| 3B
| DP2
| 3E
| 3F
| 3A
 
|-
| 5
| 2D
| 2C
| 2G
| 2B
| DP1
| 2E
| 2F
| 2A
 
|-
| 6
| 1D
| 1C
| 1G
| 1B
| MAX
| 1E
| 1F
| 1A
 
|-
| 7
| Beep
| Diode
| Bat
| Hold
| -
| ~
| RS232
| Auto
 
|-
| 8
! colspan="8" | Checksum
 
|}
 
=== Segment lettering ===
 
{{7seg|A|F|B|G|E|C|D}}
 
=== Mode byte ===
 
{| border="0" style="font-size: smaller" class="alternategrey sigroktable"
|-
! style="width: 2em;" | Value
! Meaning
 
|-
| 0
| DC V
 
|-
| 1
| AC V
 
|-
| 2
| DC uA
 
|-
| 3
| DC mA
 
|-
| 4
| DC A
 
|-
| 5
| AC uA
 
|-
| 6
| AC mA
 
|-
| 7
| AC A
 
|-
| 8
| Ohm
 
|-
| 9
| Capacitance
 
|-
| 10
| Hz (dial set to Hz)
 
|-
| 11
| Hz (dial set to DCV)
 
|-
| 12
| Hz (dial set to mA/A)
 
|-
| 13
| Duty cycle (dial set to Hz)
 
|-
| 14
| Duty cycle (dial set to DCV)
 
|-
| 15
| Duty cycle (dial set to mA/A)
 
|-
| 16
| Pulse width (dial set to Hz)


The segment lettering is
|-
| 17
| Pulse width (dial set to DCV)


    |--A--|
|-
    |    |
| 18
    F    B
| Pulse width (dial set to mA/A)
    |    |
    |--G--|
    |    |
    E    C
    |    |
    |--D--|


The mode is given by the following table:
|-
| 19
| Diode


    0    DC V
|-
    1    AC V
| 20
    2    DC uA
| Continuity (beep)
    3    DC mA
 
    4    DC A
|-
    5    AC uA
| 21
    6    AC mA
| hFE
    7    AC A
 
    8    Ohm
|-
    9    Capacitance
| 22
    10  Hz (dial set to Hz)
| LOGIC
    11  Hz (dial set to DCV)
 
    12  Hz (dial set to mA/A)
|-
    13  Duty cycle (dial set to Hz)
| 23
    14  Duty cycle (dial set to DCV)
| dBm
    15  Duty cycle (dial set to mA/A)
 
    16  Pulse width (dial set to Hz)
|-
    17  Pulse width (dial set to DCV)
| 24
    18  Pulse width (dial set to mA/A)
| (Unknown)
    19  Diode
 
    20  Continuity (beep)
|-
    21  hFE
| 25
    22  LOGIC
| Temp
    23  dBm
 
    24  (Unknown)
|}
    25  Temp


== Resources ==
== Resources ==


* [http://code.google.com/p/rs22812/ rs22812.py project page] (Python interface to Radio Shack 22-812 DMM)
* [http://code.google.com/p/rs22812/ rs22812.py project page] (Python interface to RadioShack 22-812 DMM)
* [http://www.radioshack.com/graphics/uc/rsk/Support/ProductManuals/2200812A_PM_EN.pdf Radioshack 22-812 user manual] (Python interface to Radio Shack 22-812 DMM)
* [http://www.radioshack.com/graphics/uc/rsk/Support/ProductManuals/2200812A_PM_EN.pdf RadioShack 22-812 user manual]
 


[[Category:Device]]
[[Category:Device]]
[[Category:Multimeter]]
[[Category:Multimeter]]
[[Category:Supported]]

Latest revision as of 05:32, 15 December 2012

RadioShack 22-812
Radioshack 22 812 front.png
Status supported
Source code serial-dmm
Counts 4000
IEC 61010-1 CAT II (600V)
Connectivity RS232 (standard DB9 connector)
Measurements voltage, temperature, current, resistance, capacitance, continuity, diode, logic, frequency, hFE, duty cycle, pulse width
Features autorange, data hold, min/max, dBmW (600Ω)
Website radioshack.com

The RadioShack 22-812 is a 4000 counts, CAT II (600V) handheld digital multimeter with RS-232 connectivity.

It is no longer sold under this part number, and for a while, it appeared to have been discontinued. RadioShack does sell a visually identical multimeter, the RadioShack 22-039. It is not yet clear if the 22-039 is the same device as the 22-812.

Hardware

The microcontroller is an unidentifiable plastic blob.

This devices has a standard DB-9 connector at the top, and does not require a special adapter cable. The RS-232 transmitter is optically insulated from the rest of the device. The transmitter uses a separate PCB, integrated into the multimeter's housing. The RS-232 module is powered from the serial port.

Photos

  • Mugshot

  • Device, angle

  • RS-232 connector

  • Holster removed, front

  • Holster removed, back

  • Battery location

  • Opened up

  • PCB removed

  • PCB, front

  • PCB, back

  • Buttons PCB

  • RS-232 module

  • RS-232 transmitter

  • RS-232 PCB, top

  • RS-232 PCB, bottom

  • Banana sockets connecting to PCB

  • Spare fuse

  • Multimeter IC

  • Calibration pots

Protocol

The device periodically sends 9-byte packets at 4800 baud, 8n1. The packet includes a mode indicator, payload and checksum. The payload is a 1-1 mapping of the LCD segments.

Packet structure

Byte 7 6 5 4 3 2 1 0
0 Mode
1 Hz Ohms k M F A V m
2 u n dBm s % hFE REL MIN
3 4D 4C 4G 4B DP3 4E 4F 4A
4 3D 3C 3G 3B DP2 3E 3F 3A
5 2D 2C 2G 2B DP1 2E 2F 2A
6 1D 1C 1G 1B MAX 1E 1F 1A
7 Beep Diode Bat Hold - ~ RS232 Auto
8 Checksum

Segment lettering

  A  
   
F B
   
  G  
   
E C
   
  D  

Mode byte

Value Meaning
0 DC V
1 AC V
2 DC uA
3 DC mA
4 DC A
5 AC uA
6 AC mA
7 AC A
8 Ohm
9 Capacitance
10 Hz (dial set to Hz)
11 Hz (dial set to DCV)
12 Hz (dial set to mA/A)
13 Duty cycle (dial set to Hz)
14 Duty cycle (dial set to DCV)
15 Duty cycle (dial set to mA/A)
16 Pulse width (dial set to Hz)
17 Pulse width (dial set to DCV)
18 Pulse width (dial set to mA/A)
19 Diode
20 Continuity (beep)
21 hFE
22 LOGIC
23 dBm
24 (Unknown)
25 Temp

Resources

Retrieved from "https://sigrok.org/w/index.php?title=RadioShack_22-812&oldid=5307"