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Refer to Table 2 for the header character ‘{’ definition. The sign of this pressure value is determined by the header
character. The next 4 characters, ‘@#16’, contain the encoded device address and the temperature compensated
pressure reading. For this example, the extended form is used so that the pressure data is represented as a 17 bit
binary value. Using the binary format character codes found in Table 3, convert each of the 4 byte characters into the
binary value equivalent. The highlighted portion of each character below represents the 6 least significant bits.
(Parity is off, OP=N)
@=01 000000 #=00 100011 1=00 110001 6=00 110110
Using the least significant (LS) 6 bits of each of the 4 data bytes, regroup the binary numbers into the 7 bit binary
device address and 17 bit binary pressure data, which produces the 24 bit string:
000000 100011 110001 110110 = @#16 least significant 6 bits of each byte
0000001 00011110001110110 = (device ID=01) and (pressure = 15,478)
The binary format reply indicates the device address is ID=01 and the pressure reading is 15,478. Now, the decimal
point position for the pressure reading must be determined. The decimal place is in the same position as when it reads
a P1 pressure command (see Table 1). So, if this is a 17.6 psia device reading in inches water column (DU=INWC) then
there are 2 decimal places. The final reading from the binary format will be 154.78 inH
2
O . The header character for
this binary reply was ‘{‘ which indicates a positive pressure value.
(1) The grave accent character is used instead of a space to provide printable characters for debug and verification purposes.
(2) The lower case ‘j’ is used instead of the ‘*’ because the ‘*’ is interpreted as a message header character.
Table 3. Binary Format Character Codes
Binary
Format
Character
Decimal
Value
Hex
Value Binary Value
Least 6
Significant Bits
Binary
Format
Character
Decimal
Value
Hex
Value Binary Value
Least 6
Significant Bits
@ 64 40 0100 0000 000000 ‘
(1)
96 60 0110 0000 100000
A 65 41 0100 0001 000001 ! 33 21 0010 0001 100001
B 66 42 0100 0010 000010 " 34 22 0010 0010 100010
C 67 43 0100 0011 000011 # 35 23 0010 0011 100011
D 68 44 0100 0100 000100 $ 36 24 0010 0100 100100
E 69 45 0100 0101 000101 % 37 25 0010 0101 100101
F 70 46 0100 0110 000110 & 38 26 0010 0110 100110
G 71 47 0100 0111 000111 ’ 39 27 0010 0111 100111
H 72 48 0100 1000 001000 ( 40 28 0010 1000 101000
I 73 49 0100 1001 001001 ) 41 29 0010 1001 101001
J 74 4A 0100 1010 001010 j
(2)
106 6A 0110 1010 101010
K 75 4B 0100 1011 001011 + 43 2B 0010 1011 101011
L 76 4C 0100 1100 001100 , 44 2C 0010 1100 101100
M 77 4D 0100 1101 001101 - 45 2D 0010 1101 101101
N 78 4E 0100 1110 001110 . 46 2E 0010 1110 101110
O 79 4F 0100 1111 001111 / 47 2F 0010 1111 101111
P 80 50 0101 0000 010000 0 48 30 0011 0000 110000
Q 81 51 0101 0001 010001 1 49 31 0011 0001 110001
R 82 52 0101 0010 010010 2 50 32 0011 0010 110010
S 83 53 0101 0011 010011 3 51 33 0011 0011 110011
T 84 54 0101 0100 010100 4 52 34 0011 0100 110100
U 85 55 0101 0101 010101 5 53 35 0011 0101 110101
V 86 56 0101 0110 010110 6 54 36 0011 0110 110110
W 87 57 0101 0111 010111 7 55 37 0011 0111 110111
X 88 58 0101 1000 011000 8 56 38 0011 1000 111000
Y 89 59 0101 1001 011001 9 57 39 0011 1001 111001
Z 90 5A 0101 1010 011010 : 58 3A 0011 1010 111010
[ 91 5B 0101 1011 011011 : 59 3B 0011 1011 111011
\ 92 5C 0101 1100 011100 < 60 3C 0011 1100 111100
] 93 5D 0101 1101 011101 = 61 3D 0011 1101 111101
^ 94 5E 0101 1110 011110 > 62 3E 0011 1110 111110
_ 95 5F 0101 1111 011111 ? 63 3F 0011 1111 111111