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MASTECH MAS345

MASTECH MAS345

MASTECH MAS345
Status supported
Source code serial-dmm
Counts 4000
IEC 61010-1 CAT II
Connectivity RS232
Measurements voltage, current, resistance, capacitance, temperature, hFE, diode, continuity
Features autorange, data hold, bargraph, backlight
Website p-mastech.com

The MASTECH MAS345 is a 4000 counts, CAT II handheld digital multimeter with RS232 connectivity.

It is also sold under the names Circuit Specialists CSI3451, Global Specialties Pro-70, McVoice M-345pro, Sinometer MAS345. and Velleman DVM345DI.

1 The software shipped by Circuit Specialists is MasView 1.1.

Hardware

Multimeter:

  • Main chip: MASTECH Japan M343-01 F0951D174 (80 pins, 16 + 16 + 24 + 24)
  • 14-stage binary counter/oscillator: ST 74HC4060 (datasheet) (marking: "ST 74HC4060 N00U732")
  • Precision perational amplifier: Texas Instruments OP07C (datasheet) (marking: "12AL9JM 0P07CP")
  • CMOS multifunctional time base circuit: Green Sea Technology GC7555AP (datasheet, English translation) (marking: "GC7555AP AA7057HS") This is an NE555 compatible chip, apparently.
  • General-purpose photocoupler: Sharp PC817 (datasheet) (marking: "B > B5 PC817 Sharp") "B": model = PC817X2J000F/PC817XF2J00F, ">": China factory, "B5": date code == May 1991
  • General-purpose photocoupler: Sharp PC817 (datasheet) (marking: "B > B6 PC817 Sharp") "B": model = PC817X2J000F/PC817XF2J00F, ">": China factory, "B6": date code == June 1991
  • Crystal: ca. 32kHz
  • Fuse: 15A/250V (6x30mm) (for the 10A jack; interestingly the PCB silkscreen says "20A" for that jack)

RS232 cable:

Driver

Uses the driver mastech-mas345. You'll generally need the 'conn' driver option to specify the serial device to use.

Example:

 sigrok-cli --driver mastech-mas345:conn=/dev/ttyUSB0 --samples 10

Photos

Mastech Mas345 Pcb Front4 Mastech Mas345 Pcb Front4

Mastech Mas345 Package Contents Mastech Mas345 Package Contents

Mastech Mas345 Device Back Mastech Mas345 Device Back

Mastech Mas345 Package2 Mastech Mas345 Package2

Mastech Mas345 Pcb Front3 Mastech Mas345 Pcb Front3

Mastech Mas345 Device Front Mastech Mas345 Device Front

Mastech Mas345 Temperature Sensor Mastech Mas345 Temperature Sensor

Mastech Mas345 Texas Instruments 12al9jm Mastech Mas345 Texas Instruments 12al9jm

Mastech Mas345 Pcb Front2 Mastech Mas345 Pcb Front2

Mastech Mas345 Device Front Mastech Mas345 Device Front

Mastech Mas345 Pcb Bottom2 Mastech Mas345 Pcb Bottom2

Mastech Mas345 Display1 Mastech Mas345 Display1

Mastech Mas345 Device Front Rubber Mastech Mas345 Device Front Rubber

Mastech Mas345 Package1 Mastech Mas345 Package1

Mastech Mas345 Lcd1 Mastech Mas345 Lcd1

Mastech Mas345 Pcb Front1 Mastech Mas345 Pcb Front1

Mastech Mas345 Package3 Mastech Mas345 Package3

Mastech Mas345 Device Plastic Mastech Mas345 Device Plastic

Mastech Mas345 Gc7555ap Mastech Mas345 Gc7555ap

Mastech Mas345 Pcb Front Displayremoved Mastech Mas345 Pcb Front Displayremoved

Mastech Mas345 Mastech M343 01 Mastech Mas345 Mastech M343 01

Mastech Mas345 Pcb Bottom1 Mastech Mas345 Pcb Bottom1

Mastech Mas345 Display2 Mastech Mas345 Display2

Mastech Mas345 Lcd2 Mastech Mas345 Lcd2

Mastech Mas345 Probes Mastech Mas345 Probes

Mastech Mas345 St 74hc4060 Mastech Mas345 St 74hc4060

Mastech Mas345 Sharp Pc817 Mastech Mas345 Sharp Pc817

Mastech Mas345 Device Open Mastech Mas345 Device Open

Mastech Mas345 Pcb Rs232 Connector Mastech Mas345 Pcb Rs232 Connector

Protocol

The protocol is (partially) documented in the vendor software's "Help" window (seems to apply to MAS343, MAS344, and MAS345; the M9803R protocol is different).

See Multimeter_ICs#Metex_14-byte_ASCII for the DMM IC protocol.

Resources