HMR3100
SENSOR PRODUCTS
Data Description
The HMR3100’s onboard microcontroller sends a three byte status/heading data packet reply as the RTS line is brought low. The data is normally formatted in binary with the first byte being either 80(hex) or 81(hex).
If that first byte LSbit is flagged high (81 hex), it means magnetic distortion maybe present and a
The remaining two bytes are the heading (in degrees) in MSB to LSB format. There is some data interpretation needed to derive the heading. For example, the 80 02 85 (hex) Byte pattern correlates to 322.5 degrees.
This is done by taking the MSB hex value, converting it to decimal (base ten) representation (e.g. 02 decimal) and multiplying it by 256. Then the LSB is decimalized (e.g. 85(hex) to 133(decimal)) and added to the 512(decimal) MSB. The total (512+133=645) is then divided by two to arrive at a 322.5 degree heading. This data format permits the 0.5° resolution in two bytes by doing the binary to decimal conversion and division by two.
Development Kit
The HMR3100 Development Kit includes additional hardware and Windows demo program software to form a development kit for electronic compassing. This kit includes the appropriate HMR3100 Printed Circuit Board (PCB) module soldered to an intermediate circuit board using a 0.8” spacing pin arrangement. The intermediate board assembly plugs into an
The
Figure 5
HMR3100 Kit Hardware
Solid State Electronics Center • www.magneticsensors.com • (800)