ANY-maze Help > I/O devices supported by ANY-maze > Test equipment designed specifically for ANY-maze > The Orofacial pain assessment device (OPAD) cage > OPAD reference information > The OPAD cage weight sensor

The OPAD cage weight sensor

The weight sensor was only included in early versions of the OPAD device.

Introduction

The bottle in the OPAD cage is mounted on a weight sensor which is continuously monitored during a test. This allows the system to determine how much liquid the animal consumes.

In fact, the sensor cannot always be accurately read while the animal is drinking, because the licking of the bottle spout causes the sensor's value to fluctuate. As a result, you may find that the value only changes when the animal ends a drinking bout.

Calibration

The weight sensor is shipped in an uncalibrated state, so you must calibrate it before you can use your OPAD cage. The calibration process is described in detail here.

We recommend you recalibrate the sensor under the following conditions:

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Recalibrate once a month, during normal use.

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If you don't use the cage for a long period, recalibrate before performing any tests.

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If you move the cage to a different location, recalibrate before performing any tests.

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If you want to use the cage in an ambient temperature that is more than 10°C different to the temperature at which it was calibrated.

Details

The weight sensor is accurate to 100mg, which means that it can be affected by vibrations. For example, if you bang on the bench or slam a door, the sensor will probably detect this. In fact, although the sensor will detect such events, the software which reads it will ignore them, because it only 'reads' the sensor when the data it is providing is stable. This has an important repercussion - if the sensor is subject to some form of continuous vibration, then the software may never see it as being stable and therefore may never read its value at all. For this reason, it's a good idea to site your OPAD cages away from sources of vibration such as centrifuges or air conditioning units.

The sensor is reasonably robust, but you can damage it by rough handling. For this reason, we recommend taking care when removing the water bottle - try not to twist or pull the bottle's mounting pillar.

ANY-maze help topic T1214