Application Notes Cost Effective Scaleable Analog Sensors

Cost Effective Scaleable Analog Sensors

The VERIS 721 (loop-powered, 4-20 mA) and 722 (self-powered, 0-5 VDC) analog sensors provide a cost-effective means of measuring the load on a fan or pump motor. The sensors provide automation-compatible outputs which are proportional to the primary current flowing in the sensed conductor. Unlike other devices which have fixed amperage ranges, the 721 and 722 have adjustable scaling ranges for maximum resolution. The scaling for each of the sensors is indicated on the face of the sensor and can be adjusted using a standard screwdriver to the maximum anticipated input.
The 721 provides a minimum scale of 5A, which is ideal for interfacing these sensors to 5A secondary CT's.

Typical Hawkeye 721 installation:

Installation instructions (Note: Consult installation instructions with product prior to installation):

Disconnect power from the source
Connect wiring as indicated above
Adjust span potentiometer to expected maximum primary amperage (e.g., FLA)
Start motor and verify output at panel
Determine software scaling using the following formula:

Amps/mA ratio = Max amps (from #3 above) / 16

Primary sensed amps = (mAoutput -4) * (Amps/mA )

Typical Hawkeye 722 installation:

Installation instructions (Note: Consult installation instructions with product prior to installation):

Disconnect power from the source
Connect wiring as indicated above
Adjust span potentiometer to expected maximum primary amperage (e.g., FLA)
Start motor and verify output at panel
Determine software scaling using the following formula:

Amps/V ratio = Max amps (from #3 above) / 5

Primary sensed amps = (Voutput) * (Amps/V)

Applications are suggestions. Field applications vary; since manufacturer does not install the devices, it is up to the installer to ensure suitability and compliance to appropriate codes.