HMR2300-D00-232 Honeywell, HMR2300-D00-232 Datasheet - Page 10

• Manufacturer Part Number: HMR2300-D00-232
• Manufacturer: Honeywell

Specifications of HMR2300-D00-232

• Lead Free Status / RoHS Status: Not Compliant

HMR2300
SENSOR PRODUCTS
between a Set and Reset state. Note that the first three readings immediately after these commands will be invalid
due to the uncertainty of the current pulse to the sensor sample time.
DEFAULT AND RESTORE COMMANDS
The Defaut Settings command (*ddD) will force the HMR2300 to all the default parameters. This will not be a
permanent change unless a Store Parameter command (*ddSP) is issued after the Write Enable command. The
Restore Settings command (*ddRST) will force the HMR2300 to all the stored parameters in the EEPROM.
OUTPUT SAMPLE RATES
The sample rate can be varied from 10 samples per second (sps) to 154 sps using the *ddR=nnn command. Each
sample contains an X, Y, and Z reading and can be outputted in either 16-bit signed binary or binary coded decimal
(BCD) ASCII. The ASCII format shows the standard numeric characters displayed on the host computer display.
Some sample rates may have restrictions on the format and baud rate used, due to transmission time constraints.
There are 7 Bytes transmitted for every reading binary format and 28 Bytes per reading in ASCII format.
Transmission times for 9600 baud are about 1 msec/Byte and for 19,200 baud are about 0.5msec/Byte. The
combinations of format and and baud rate selections are shown in the above Table. The default setting of ASCII
format and 9600 baud will only transmit correctly up to 30 sps. Note the HMR2300 will output a higher data settings,
but the readings may be incorrect and will be at alower output rate than selected.
For higher sample rates (>60 sps), it is advised that host computer settings for the terminal preferences be set so a
line feed <lf> is not appended to the sent commands. This slows down the reception of data, and it will not be able to
keep up with the incoming data stream.
INPUT SIGNAL ATTENUATION
Magnetic signals being measured will be attenuated based on the sample rate selected. The bandwidth, defined by
the 3dB point, is shown in the above Table for each sample rate. The default rate of 20 sps has a bandwidth of 17Hz.
The digital filter inside the HMR2300 is the combination of a comb filter and a low pass filter. This provides a linear
phase response with a transfer function that has zeros in it.
When the 10 or 20 sps rate is used, the zeros are at the line frequencies of 50 and 60 Hz. These zeros provide better
than 125 dB rejection. All multiples of the zeros extend throughout the transfer function. For example, the 10 and 20
sps rate has zeros at 50, 60, 100, 120, 150, 180, ... Hz. The multiples of the zeros apply to all the sample rates
against the stated notch frequencies in the above Table.
COMMAND INPUT RATE
The HMR2300 limits how fast the command bytes can be recieved based on the sample rate selected. The above
Table shows the minimum time between command bytes for the HMR2300 to correctly read them. This is usually not
a problem when the user is typing the commands from the host computer. The problem could arise from an
application program outputting command bytes too quickly.
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