Maintenance, Test & Measurement, Calibration


Isolated A-D loadcell transformer

November 2005 Maintenance, Test & Measurement, Calibration

The SNAP-AILC module provides one channel of transformer and optically isolated analog-to-digital conversion for loadcell inputs. This module supports 6- or 4-wire loadcells. (4-wire is at reduced performance.) It provides isolated 10 V d.c. bridge excitation for up to four parallel 2 mV/V or 3 mV/V 415/350 Ω loadcells as a loadcell front end. 24 V d.c. is required at the separate connector on top of the module for the isolated 10 V d.c. bridge excitation.

The bridge and 10 V d.c. bridge power is isolated from the 24 V d.c. bridge source and the 5 V d.c. source used by the mounting rack. The 24 V d.c. input is reverse polarity protected, and it may be used for multiple modules. The 10 V d.c. bridge source is current limited so that an external fault on the loadcell is isolated and will not affect another loadcell module.

There are two channels of data: channel 1 is unfiltered, and channel 2 is filtered. Filtered data has a fast settling feature with a programmable fast settle level. The module snaps into Opto 22 SNAP B- & M-series mounting racks. The field connections are made by a pluggable terminal strip located on top of the module.

Features

* Works with 2 mV/V and 3 mV/V loadcells.

* Provides isolated 10 V d.c. bridge excitation for up to four 350 Ω loadcells.

* Powered by a single 5 V d.c. power source supplied by rack.

* Convenient pluggable wiring terminals, including terminals for external 24 V d.c. power supply, which converts to isolated 10 V d.c. for bridge excitation.

* Rugged packaging.

There are two channels of data on the SNAP-AILC module. The first channel provides raw Analogue-to-Digital (ADC) data, while the second channel provides filtered data. Filtering is configured in ioControl software using two commands: Set Analogue Load Cell Filter Weight and Set Analogue Load Cell Fast Settle Level. The Set Analogue Load Cell Filter Weight command filters noise on the filtered channel of a loadcell module to a range of 0 to 255 (1 byte), at the expense of settling time. The filtered reading is calculated from the ADC reading after every ADC conversion. For maximum resolution, the filter weight is set to less than half the peak-to-peak system noise as seen while trending the data in ioDisplay.

The Set Analogue Load Cell Fast Settle Level command sets the fast settling trigger level (FSTL). The filtered weight is reduced when the difference between the ADC data and the filtered data is greater than the FSTL. This feature is useful to decrease settling time when there are large step changes in the loadcell output and a large filter weight.



Credit(s)



Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

Collect data three times faster
SKF South Africa Maintenance, Test & Measurement, Calibration
SKF has extended its renowned Microlog Analyzer family of data collection devices with the addition of the Microlog Analyzer dBX. Currently SKF’s most powerful diagnostic tool, this cutting-edge device redefines diagnostic capabilities, enabling users to take measurements three times faster than its predecessor.

Read more...
The criticality of maintenance in the water and wastewater segment
Schneider Electric South Africa Maintenance, Test & Measurement, Calibration
In a time of water shedding, climate change and ageing infrastructure, the importance of maintenance and support in the water and wastewater segment cannot be overstated.

Read more...
How dry ice blasting is revolutionising the mining industry
Maintenance, Test & Measurement, Calibration
Dry ice blasting has emerged as a game-changing technology for the mining industry, offering a range of advantages that are reshaping traditional cleaning methods.

Read more...
Quality test tools save costs at pulp and paper mill
Comtest Editor's Choice Maintenance, Test & Measurement, Calibration
A case study on how preventive maintenance and a few good test tools avoided unnecessary motor replacements at a pulp and paper company.

Read more...
The logical solution to oil and gas industry corrosion
Maintenance, Test & Measurement, Calibration
The consequences of corrosion in the oil and gas industry can be astronomical. The simple culprit is metal reacting with oxygen and moisture, degrading it back to its natural state.

Read more...
Lube tip: foaming is affected by oil level
Wearcheck Maintenance, Test & Measurement, Calibration
In a circulating system, it is crucial to check the oil level before introducing anti-foam agents to address a foaming problem.

Read more...
Microfine filtration boosts fuel quality and reduces equipment failure
Maintenance, Test & Measurement, Calibration
The path to contamination-free fuels relies on a combined effort from refiners to transporters, storage depots, handlers and end users. Prior to use, fuels can be polished with multi-pass microfine filtration systems such as those exclusively manufactured by ISO-Reliability Partners.

Read more...
Supporting capital investment in machinery
Maintenance, Test & Measurement, Calibration
Industrial and mining operations are under increased financial pressure in the current economic and social climate in South Africa. This means that when businesses make capital investments in new equipment, they need to be sure that the machinery will function optimally for as long as possible.

Read more...
High-accuracy automated pressure calibrator
Maintenance, Test & Measurement, Calibration
The Additel 762 Automated Pressure Calibrator is unlike any other pressure calibrator on the market. This revolutionary product is a complete turnkey solution for automation of pressure calibration work ...

Read more...
Handheld pressure calibrator
Maintenance, Test & Measurement, Calibration
The 273Ex from Additel is an intrinsically safe handheld multifunctional pressure calibrator with an intuitive colour touchscreen interface. The unit features built-in quick test tasks and optional HART ...

Read more...