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 Radioshack 22-812 is a 4000 counts, CAT II handheld digital multimeter with RS-232 connectivity. The 22-812 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 22-039. It is not yet clear if the [http://www.radioshack.com/product/index.jsp?productId=12988573 Radioshack 22-039] is the same device as the 22-812.
The '''RadioShack 22-812''' is a 4000 counts, CAT II (600V) handheld digital multimeter with RS-232 connectivity.


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.
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 ==
== Hardware ==


TODO
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.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_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 20: 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


The segment lettering is
|-
| 1
| Hz
| Ohms
| k
| M
| F
| A
| V
| m


    |--A--|
|-
    |     |
| 2
    F    B
| u
    |    |
| n
    |--G--|
| dBm
    |    |
| s
    E    C
| %
    |    |
| hFE
    |--D--|
| REL
| MIN


The mode is given by the following table:
|-
| 3
| 4D
| 4C
| 4G
| 4B
| DP3
| 4E
| 4F
| 4A


    0   DC V
|-
    1   AC V
| 4
    2   DC uA
| 3D
    3   DC mA
| 3C
    4   DC A
| 3G
    5   AC uA
| 3B
    6   AC mA
| DP2
    7   AC A
| 3E
    8   Ohm
| 3F
    9   Capacitance
| 3A
    10   Hz (dial set to Hz)
 
    11   Hz (dial set to DCV)
|-
    12   Hz (dial set to mA/A)
| 5
    13   Duty cycle (dial set to Hz)
| 2D
    14   Duty cycle (dial set to DCV)
| 2C
    15   Duty cycle (dial set to mA/A)
| 2G
    16   Pulse width (dial set to Hz)
| 2B
    17   Pulse width (dial set to DCV)
| DP1
    18   Pulse width (dial set to mA/A)
| 2E
    19   Diode
| 2F
    20   Continuity (beep)
| 2A
    21   hFE
 
    22   LOGIC
|-
    23   dBm
| 6
    24   (Unknown)
| 1D
    25   Temp
| 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)
 
|-
| 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 ==
== 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]
* [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"