Windmill Software

Data acquisition and control

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751: Multifunction Data Acquisition USB Unit

751 Multi-function USB Data Acquisition with Windmill Software: 16 analogue inputs, 32 digital i/o, 8 counters

Sale: Was 595 now just 295!

For 16 differential analogue inputs, 16 digital inputs/outputs and 8 counters. You can connect eight 751s to one PC. With the addition of suitable Microlink 59x conditioning units, you can also monitor thermocouples, strain gauges, pressure transducers and current. Includes Windmill data acquisition software for logging, charting, output control and direct data transfer to Excel.

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Measuring pH

751-pH: pH Measurement via PC's USB port

Sale: Was 1095 now just 795!

Monitor 12 pH probes. With digital I/O & counting. Expand to measure temperature, pressure, flow, level etc.

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Strain Gauge Monitoring

Strain Measurement:  USB Data Acquisition Unit, Strain Gauge Connection Box, Windmill Software, free technical support

Sale: Was 775 now just 475!

Monitor 16 strain gauges, balanced bridges like pressure transducers or voltage signals. Connect 8 units to 1 PC and monitor 128 strain gauges. Readings in microstrain. Zero reference level can be set in Windmill software. Plus digital input & output and counting.

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Best Sellers

Microlink 840: Versatile Data Logging over Ethernet and Internet

Microlink 840: Versatile data logging

The culmination of 30-years of experience designing data acquisition and control systems has resulted in this extremely versatile, compact unit which lets you monitor analogue transducers, digital sensors, utility meters, machines and digital status. It can also raise alarms and control digital outputs.

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Microlink 851-TC: Temperature Data Logger with Digital I/O

851-TC: Thermocouple and voltage data logger with digital I/O and counting

Data logger monitors 16 thermocouples or voltage signals, provides digital input and output, and frequncy and event counting. Communicates with PC over TCP/IP (eg Ethernet and Internet).

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750: Low Cost Measurement & Control

750 USB Data Acquistion with Windmill Software: analogue input, digital i/o, counters, free technical support

16 analogue inputs, 16 digital inputs/outputs, 8 counters and Windmill logging and control software: all for 150. Connect up to 8 units to a PC. Data saved in text files, or passed directly to Excel.

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Microlink 751-SG: Strain Gauge Measurement, Digital I/O and Counters

DAQ Catalogue | Data Acquisition Hardware: USB |  Microlink 751-SG: Strain Gauge Measurement, Digital I/O and Counters

Strain Measurement:  USB Data Acquisition Unit, Strain Gauge Connection Box, Windmill Software, free technical support

Strain Measurement: USB Data Acquisition Unit, Strain Gauge Connection Box, Windmill Software, free technical support

Price: 475.00 (Excluding VAT at 20%)


Sale: Was 775 now just 475!

Windmill's 751-SG package has lets you monitor 16 strain gauges, balanced bridges like pressure transducers and voltage signals. This USB unit also provides 32 digital inputs and outputs and 8 counters. Connect eight units to one PC and monitor 128 strain gauges.


  • Monitor strain gauges, or voltage signals, through 16 differential input channels
  • Switch up to 32 digital outputs
  • Monitor up to 32 digital inputs
  • Count events with up to 8 counters
  • Options to also monitor temperature, pressure and current
  • Includes the powerful yet easy-to-use Windmill Software for Windows: no programming required
  • Connect up to 8 units to one PC, giving 128 strain or voltage inputs and 256 digital inputs and outputs
  • Powered from the PC
  • Low power consumption
  • Connects over USB
  • Choice of four analogue input ranges, selected with Windmill software individually for each channel
  • Alternatively, choose automatic ranging and let the software match the input signal as closely as possible
  • Integrating analogue-to-digital converter reduces electrical noise
  • Use Windmill to select the resolution of the A-D converter from 12- to 18-bits: choose high throughput or high resolution
  • Automatic recalibration
  • Comprehensive User Manual
  • Free technical support for life and money-back guarantee if not satisfied

Strain Measurement

The Windmill 751-SG package lets you monitor strain gauge bridges and balanced bridges such as pressure transducers. You can configure individual channels to accept any of these inputs:

  • voltage
  • quarter bridge: single strain gauge
  • half bridge: tensile + compressive strain gauge
  • half bridge: normal + transverse strain gauge
  • full bridge: 2 tensile + 2 compressive gauges
  • full bridge: 2 normal + 2 transverse gauges
  • full bridge: tensile normal + compressive normal + tensile transverse + compressive transverse gauge

Strain gauges need an external excitation voltage to supply sufficient current to keep all the bridge circuits energised. The 751-SG package provides four sets of 16 screw terminals giving + and - excitation and signals for each of 16 bridges. Two 1 kOhm termination resistors are mounted in half bridge configuration whilst high quality 350 and 120 Ohm resistors can be provided for the completion of quarter bridges.

When a bridge input is selected the Windmill software monitors excitation voltage and performs the bridge calculation to produce a reading in microstrain. This eliminates errors due to changes in excitation voltage.

The initial unstrained bridge measurement is often much larger than the change in signal due to strain. If this initial value is not accounted for, it restricts the resolution you can obtain - i.e. the smallest signal you can measure. Windmill software can zero or balance the bridge, nulling the offset of the initial voltage. So instead of measuring over a wide range, 0 to 0.5 V for example, you can choose a narrow range such as 0 to 0.01 V.

Each range is divided into a fixed number of steps: the resolution. The smaller the range and the larger the resolution, the more precise the reading. The 751-SG offers a choice of resolutions from 12-bit for fast sampling to 18-bit for greater precision.

If you would like more information on strain measurement techniques, there is an article on our Data Acquisition Intelligence site.

Digital Inputs and Outputs

The 751-SG provides 32 digital I/O lines, arranged in four groups of 8. Use Windmill to choose whether each group 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 USB unit 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.


Windmill Software is included in the 751-SG package. This modular suite offers data logging, charting, alarm indication, output control and real-time 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 hardware yourself, you can use the IML Tools to do so.

Windmill Chart software

Windmill 751-SG Unit 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
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

Download the 751-SG User Manual...

DAQ Catalogue | Data Acquisition Hardware: USB |  Microlink 751-SG: Strain Gauge Measurement, Digital I/O and Counters