NetPod 4000

General Description

The NetPod 4000 series instruments can be used as high precision strain gauge monitoring instruments when fitted with the NPAI24-SG X or NPAI16-SG X range of interface cards.

Each of the NPAI24-SG X and NPAI16-SG X cards contain isolated strain gauge exitation, bridge completion resistors, individual Sigma Delta ADC and 1000V opto-isolation.

A range of different strain gauges can be attached to the input cards including all of the popular 120, 350, 500 and 1K Ohm devices. A simple software configuration option enables the sensor value to be assigned within the driver software. Due to the high dynamic range of this card only a small bridge excitation voltage is required. This has the added advantage of minimising the self heating effect within the gauges.

Part Numbers

Simultaneous Sampling

The NetPod 4000 series instruments when fitted with the NPAI-24 XXX or NPAI-16 XXX interface cards offers simulataneous sampling on all inputs. The use of the strain gauge cards offers enginners the oppurtunity to use the instruments in both static and dynamic signals applications.

Full Strain Bridge , Half Strain Bridge, Quarter Bridge , Opto-isolator

Card Layout

Figure 1

Specification NPAI24-SG X cards

Figure 1 shows a picture of the NPAI24-SG1 full bridge strain gauge card only. The NPAI16-SG1 card is physically the same size as the 24 bit card and uses exactly the same connector pin-outs and has all of the same features.

Half Bridge Interface - NPAI24-SG2 & NPAI16-SG2

Quarter Bridge Interface - NPAI24-SG2 & NPAI16-SG2

Each of the strain gauge input cards for the 4000 series instruments utilises an opto-isolated protection system similar to that shown in Figure 6.

The output of the Sigma Delta ADC passes through the isolator prior to connection on the processor card. The isolator overs to100V protection to the card

The strain gauge bridge excitatiion is also protected. Should a short circuit or any type of failure occur then only the card effected will show an error and will not cause any problems to any other interface within the instrument.