M3 Digital Display

Metro M1/M3 Air With Pneumatic Electronic Digital Display

When you need dimensional control for your air gaging equipment, you need a device that can handle all aspects at once—while also providing you with detailed and easy-to-read results. If that sounds like the exact tool your business needs, then you need the Metro M1/M3 Air with pneumatic, electronic, and digital display. This precision air gage offers accurate results in a compact form.

In order to offer the best compactness, Metro designs special devices according to the probes your using. You can contact Metro to help you to pick the most suitable device according to your needs. The Metro M1/M3 Air units can work with any of your air gages to provide 1 (M1) or 2 (M3) measurement characteristics.

In case you weren’t sure, it is possible to connect probes from different sources or brand thanks to the M-Bus modules. No matter what you need to do, this air gaging product will be able to help you get it done. Luckily, Air Gaging is here to answer any questions you might have about this device before you make a purchase, so feel free to reach out to us today.

Product advantages 

  •         Touch screen
  •         Very easy to use
  •         Economic
  •         USB communication as a keyboard to a computer
  •         Static and dynamic measurement
  •         Designed for industry condition
  •        Combined measurement (with 2 probes), sums, differences ...


  • 4.3” Resistive touch screen display (glove-friendly use)
  • Digital readout with multiple communication capabilities (USB, remote control the device or send the measurement to an external system).
  • 1 or 2 measurement configuration (2 characteristics only on M3)
  • Calibration in 2 or 3 points
  • Resolution up to 0.01µm
  • Filtering function for very high measurement stability not depending on the air gage.
  • Different display modes with or without tolerances: analog (needle indicator), digital
  • Tolerance limits and control limits (Warnings).
  • Absolute or relative measurement
  • Direct or dynamic measurement (Min, Max, Max-Min, Average, Median)
  • USB communication "virtual keyboard"
  • USB Stick connection for data export (CSV file)
  • Modbus-RTU or ASCII Communication on RS232
  • Sorting by classes of size, up to 16 classes by characteristic, with useful colored indicator.
  • Possibility to connect up to 4 optional I/O module with 8 optocoupled I/O (= max 32 I/O)
  • Possibility to connect a multi-function footswitch (measurement transfer, calibration etc.)
  • Alarm with temperature variation (option)
  • Temperature compensation (option)
  • Configuration possible by a QR code
  • Easy to use and reliable


Many functions and measurement mode can be selected through the touch screen:

  • Tolerance limits, Control limits (warnings)
  • Calibration / Preset
  • Different display modes
  • Direct or dynamic measurement (Max, Min, Max-Min, Average, Median)
  • Sorting by classes of size, up to 16 classes by characteristic with a colored indicator
  • Possibility to lock selected functions with a password
  • Display resolution (from 2 to 5 decimals)
  • M-Bus connector for the optional connection MBUS modules ( I/O modules or inductive probe etc.
  • Metric (µm or mm) or imperial measurements (inches)
  • Different languages installed (including Japanese, Chinese, Korean). A new language can be installed upon request
  • Data export on a USB stick (.csv file)
  • Possibility to connect a multi-function footswitch (measurement transfer, calibration, etc.)
  • Alarm with temperature variation (option)
  • Temperature compensation (option)
  • Configuration possible by a QR code
  • Easy to use and reliable

Part Numbers:

13040:  M3 with 2 inputs for air gages

11040: M1 with 1 input for an air gage

ACS-PNE-003:  Precision air preparation unit

18193:  Cable with digimatic output for Mux and Mitutoyo DP1 Printer


M3 AG:  The M3 AG has to be used with a high precision pressure set up. Metro can deliver this set up when providing the M3. It is recommended to do so to ensure the best use of the air gauging 

MB-IO:  This M-Bus module is fitted with 8 input/outputs isolated with optocouplers allowing to get additional functionalities, for example, output for Go/noGo, input for preset or start dynamic measurement... The M-Bus modules are mounted on an aluminum profile allowing to mount them on a standard DIN rail. More information on this page: M-BUS 

As an option, it is possible to connect up to 4 M-Bus I/O module fitted with 8 optocoupled inputs/outputs. (= max 32 I/O).  A screen allows the user to assign a function to a pin of the module very easily. 8 virtual Buttons/lamps allow for easy testing of your wires.

Available functions:

  • Go/NoGo
  • Calibration/Preset
  • Start dynamic measurement
  • Measurement transfer
  • Zero
  • Stop

Multifunctional Footswitch (P/N 18020):  The footswitch can be configured in different ways: preset, measurement transmissions, start dynamic measurements, and more.

M-Bus Cable for M3 (P/N 81213-1.5):  This cable allows to connect the compatible M-Bus modules (MB-IO, MB-RL and MB-TP) on an M3 display unit (MB-IO, MB-RL and MB-TP)

RS232 to Digimatic communication cable (P/N 18193):  This cable allows for the M1/M3 display connection to a multiplexer Mux from Metro.

RS232 to USB communication cable (P/N 45173):  This cable allows for the M1/M3 display t to communicate with a computer.  This creates a virtual COM port on the computer and is its delivered with a drive in CD format.


USB Connection

The M1/M3  is fitted with a mini-USB connector with 2 functions : 

  1. Power supply through a wall-mounted transformer. This transformer supplies a regulated 5V/1A DC voltage. 
  2. Measurement transmission. If you connect your M1/M3 to a PC, the PC will detect and install automatically the M1 as a standard USB keyboard with the standard drivers of your operating system (Windows, Mac OS, etc.). When you will send the measurement, the value will be written on your PC screen where your cursor is, in the same way as it would have been typed with a keyboard. 

No need to install any specific driver or software.



The RS232 interface allows us to monitor and configure all the M1 or M3 functions through ASCII commands or MODBUS-RTU protocol. 

The M1/M3 is compatible with several SPC software, like Q-DAS® /qs-STAT®



Below are examples of the graphic interface used on the M1 or M3 units.



Below is an example of the input breakdown for the M1 which is similar to that of the M3 (in which you can input 2 air gages).


Measurement of a 3mm internal diameter precision automotive part.


Measurement of 2mm external diameter on a diesel injector part.  This is utilizing a high resolution air ring directly connected to the M1 display.


Measurement of internal diameter on a Honing machine. The air flow can "clean" the part by removing the oil at the measuring point.

Call us today: (815) 242-0027

We will come up with a solution that fits your needs.