Rosemount 2700, Инструкция по эксплуатации, Страница: 42 / 94

A-8
MODEL 2700 APPENDIX A
SERIAL COMMUNICATIONS PROTOCOL
From 2700 ADDR CMD SNRM SNRL A7 A6 A5 A4 A3 A2 A1 A0
Continued B7 B6 B5 B4 B3 B2 B1 B0
To 2700 81H 6CH 30H 30H
From 2700 81H 6CH 30H 30H 32H 38H 31H 39H 41H 37H
‘0’ ‘0’ ‘2’ ‘3’ ‘1’ ‘9’ ‘A’ ‘7’
Continued 33H 36H 30H 30H 30H 30H
‘3’ ‘6’ ‘0’ ‘0’ ‘0’ ‘0’
Continued 43H 43H 34H 31H
‘C’ ‘C’ ‘4’ ‘1’
Measurement value format is floating-point which corresponds to IEEE Std 754-1985.
Primary Measurement
A7 A6 A5 A4 A3 A2 A1 A0
‘2’ ‘3’ ‘1’ ‘9’ ‘A’ ‘7’ ‘3’ ‘6’
A7 A6 A5 A4
‘2’ ‘3’ ‘1’ ‘9’
M07 M06 M05 M04 M03 M02 M01 M00 M15 M14 M13 M12 M11 M10 M09 M08
0 0 1 0 0 0 1 1 0 0 0 1 1 0 0 1
A3 A2 A1 A0
‘A’ ‘7’ ‘3’ ‘6’
E00 M22 M21 M20 M19 M18 M17 M16 S00 E07 E06 E05 E04 E03 E02 E01
1 0 1 0 0 1 1 1 0 0 1 1 0 1 1 0
From IEEE Std 754-1985:
measurement value = (-1)^sign * 2^(exponent-127) * 1.mantissa
sign = S00
exponent = E07 E06 E05 E04 E03 E02 E01 E00
mantissa
= (M22 M21 M20 M19 M18 M17 M16 M15 M14 M13 M12 M11 M10 M09
M08 M07 M06 M05 M04 M03 M02 M01 M00) / 2^23
sign = 0
exponent = 0 1 1 0 1 1 0 1
= 109
mantissa = (0 1 0 0 1 1 1 0 0 0 1 1 0 0 1 0 0 1 0 0 0 1 1)/2^23
= ( 2 7 1 9 2 3 )/2^23
= (271923 hex) / 2^23
= (2562339) / 8388608
= 0.3054546
measurement value = (-1)^0 * 2^(109-127) * 1.3054546
= 4.979914 x 10^-6
Secondary Measurement
B7 B6 B5 B4 B3 B2 B1 B0
‘0’ ‘0’ ‘0’ ‘0’ ‘C’ ‘C’ ‘4’ ‘1’
B7 B6 B5 B4
‘0’ ‘0’ ‘0’ ‘0’
M07 M06 M05 M04 M03 M02 M01 M00 M15 M14 M13 M12 M11 M10 M09 M08
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0