Rosemount 2700 - Page 38

A-4
MODEL 2700 APPENDIX A
SERIAL COMMUNICATIONS PROTOCOL
Example:
Instrument Address = 1
Byte type
Address 06DFH
Data 03H
To 2700 81H 6EH 42H 23H 30H 36H 44H 46H
From 2700 81H 6EH 42H 23H 30H 36H 44H 46H 30H 33H
‘B’ ‘#’ ‘0’ ‘6’ ‘D’ ‘F’ ‘0’ ‘3’
Example:
Instrument Address = 1
Floating-point type
Address 08AAH (Sensor 1 Primary Measurement)
Data 2319A736
Measurement value 4.979914 x 10^-6
To 2700 81H 6EH 46H 23H 30H 38H 41H 41H
From 2700 81H 6EH 46H 23H 30H 38H 41H 41H 32H 33H
‘F’ ‘#’ ‘0’ ‘8’ ‘A’ ‘A’ ‘2’ ‘3’
Continued 31H 39H 41H 37H 33H 36H
‘1 ‘9’ ‘A’ ‘7’ ‘3’ ‘6’
Measurement value format is floating-point which corresponds to IEEE Std 754-1985.
F7 F6 F5 F4 F3 F2 F1 F0
‘2 ‘3’ ‘1’ ‘9’ ‘A’ ‘7’ ‘3’ ‘6’
F7 F6 F5 F4
2’ ‘3’ ‘1’ 9’
M07 M06 M05 M04 M03 M02 M01 M00 M15 M14 M13 M12 M11 M10 M09 M08
0010 0011 0001 10 01
F3 F2 F1 F0
‘A’ ‘7’ ‘3’ ‘6’
E00 M22 M21 M20 M19 M18 M17 M16 S00 E07 E06 E05 E04 E03 E02 E01
1010 0111 0011 0110
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