Products: Microlink 751

Special offer: 50% off Microlink
Measurement Package for USB

Multi-Function USB Unit: Voltage, Temperature, Strain, pH, Current, Counting, Control, etc

Data acquisition has never been so easy as with our compact Microlink 751 unit. Just plug into your computer's USB port - and go.

  1. Plug the 751 into the computer's USB port - there is no need to switch off your PC, or even restart Windows.
  2. Connect your sensors and signals to the Microlink: thermocouples, pressure transducers, strain gauges, digital switches, etc.
  3. Install the ready-to-run Windmill software for Windows (which is bundled free with the Microlink 751) and you're ready to start logging, charting, counting and so on. No programming required.
Microlink 751 USB Unit

It really is that simple. For:



USB Plug

The USB cables shouldn't be longer than 5 metres. However, using USB hubs between cables you can reach 30 metres away from the PC. If you need longer distances, network PCs together over Ethernet (or consider our Ethernet Microlinks - contact us if you would like our advice).

Digital Inputs and Outputs

The 751 provides 32 digital I/O lines, arranged in four ports, or groups, of 8. Use Windmill to choose whether each port is an input or an output. You can read or set the state of each line individually. Alternatively, you can switch several channels at the same time.


The Microlink 751 has eight 16-bit totalling counters. Each counter starts at zero and counts pulses to a maximum of 65535. You can reset a counter at any time from Windmill software. You can use the counters in two modes: accumulating count and resetting count. In accumulating count the counter keeps counting until you reset it. In resetting count the counter shows the number of pulses since the last reading.

You can set a scale and offset factor to the count from software. For example if the pulses came from a flow meter which produced one pulse for every 50 millilitres, a scale factor of 0.05 would give a reading in litres.

The counters are found on 8 of the digital input and output lines. You can use any of these you don't need for counting as normal digital inputs: the counts are always maintained even if you don't plan to use them.

Signal Connections

The slim Microlink 751 offers pin connections for your signals. However, if you prefer to use screw-terminals these are provided with our 59x Series of units. For analogue voltages, digital I/O and counters, choose the Microlink 590. This allows many extra facilities, such as:

For current, thermocouples, strain gauges, presssure transducers and pH - choose the Microlink 590-8A, 593, 594 and pH-USB respectively.

Temperature, Strain, pH, Pressure and Current

Depending on your transducers, you might need extra hardware units to make your connections. For example, for thermocouples you will need a Microlink 593 box which provides cold junction measurement. (When monitoring thermocouples it is essential that the system knows the temperature of one of the thermocouple junctions. Housing this junction in the Microlink 593 isothermal box keeps the temperature constant, and a cold junction sensor in the box tells the system the temperature. You connect the thermocouple wires to screw terminals in the 593 isothermal box, and connect the terminals to the Microlink 751 unit with a ribbon cable. The 593 also detects broken thermocouple leads for you.)

For strain you would use a Microlink 594, which enables the 751 USB unit to monitor strain gauge bridges and balanced bridges such as pressure transducers. With the 594 unit you can configure individual channels to accept any of these inputs:

For current choose the Microlink 590-8A. This has the same extra facilities as the 590, discussed previously.

pH measurements need a Microlink pH-USB unit. This comes in two versions: one with 12 inputs and one with 16.

Chart data in real-time with Windmill


We've bundled Windmill free with the Microlink 751. This modular suite offers data logging, charting, alarm indication, output control and DDE links to other applications like Excel. You can also add process mimic generators, sequence control and many other modules. Should you wish to program the 751 yourself, you can use the IML Tools to do so.


The Microlink 751 costs just 595 pounds. You can purchase on-line through Windmill Software's USB data acquisition shop or contact us.

Hardware Specifications

Dimensions (mm)           180 x 120 x 40
Maximum length of cable   5 m
  Maximum distance from PC can be increased by 
  use of USB hubs
  # Differential inputs   16
  Maximum safe input voltage:
  Power supply on         ±48 V
  Power supply off        ±33 V
  Transient               ±300 V
  Ranges (V)              ±0.01, ±0.1, ±1, ±10
  Common mode range       ±13 V
  Relative accuracy of ranges:
   gain = 1000            ±0.1%
   gain = 1, 10, 100      ±0.05%
  Analogue to Digital Converter:
  Maximum linearity error ±0.02%
  Resolution    Integration Time    Samples/Second
  12 bits         2.5 msec          80
  13 bits         5 msec            64
  14 bits        10 msec            48
  15 bits        20 msec            32
  16 bits        40 msec            16
  18 bits       160 msec             6
  Maximum # inputs        32
  Maximum # outputs       32
  (selected through windmill in ports of 8 lines)
  Power-up state          all inputs
  Compatibility           TTL and 5 V CMOS, can be made 
                          contact closure compatible
  Range                   0 to 5 V
  Output capability       15 LSTLL loads
  Maximum I/O speed       160 channels per second
  Resolution              16 bits
  Compatibility           TTL, 5 V CMOS, can be made
                          contact closure compatible
  Input voltage range     0 to 5 V
  Maximum count speed     160 counts per second

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