KROHNE UFC 500 HART - Manual (Page 23)

HARTô Smart Communications Protocol
UFC500 Command Specification Rev: 2.0 Release Date: 9 Jun 2001
© 2001 KROHNE Mefltechnik D-47058 Duisburg Page 23
8.9 Command #139 Write Analog Output Function
Writes the function of current/pulse output.
REQUEST DATA BYTES
#0 #1
ANALOG ANALOG
OUTPUT OUTPUT
NUMBER FUNCTION
CODE CODE
RESPONSE DATA BYTES
#0 #1
ANALOG ANALOG
OUTPUT OUTPUT
NUMBER FUNCTION
CODE CODE
Data Byte #0 Analog Output Number Code, equals м1о for current output and м2о - for frequency/pulse
output
Data Byte #1 Analog Output Function Code, depends on the output type:
For current output:
0 - Off.
1 - Direction indication.
2 - 1 Dir, output traces flowrate measurements only in one (positive) direction.
3 - Forward/reverse flow, the complete flowrate dynamic range (PV Upper Range Value +
Reverse Range) is mapped onto the range of the output current. Refer also to the instrument
Operating Manual and to Commands #140, Read Current Output Parameters, #158, Read
Transmitter Variable Range Values.
4 - 2 Dir, output traces flowrate measurements in both directions, for every direction the
corresponding flowrate dynamic range (PV Upper Range Value for positive direction and
Reverse Range - for negative) is mapped onto the range of the output current. Refer also to
the instrument Operating Manual and to Commands #140, Read Current Output Parameters,
#158, Read Transmitter Variable Range Values.
5 - Transit time.
For frequency/pulse output:
0 - Off.
1 - Direction indication.
2 - 1 Dir, output traces flowrate measurements only in one (positive) direction.
3 - 2 Dir, output traces flowrate measurements in both directions.
4 - Transit time.
NOTE: The Output Function Codes are mapped onto Primary/Secondary Variable Codes in a transparent way: flowrate-
related values (ì1 Dirî, ìForward/Reverseî, ì2 Dirî) cause the assignment of corresponding Dynamic Variable to
FlowRate Transmitter Variable (refer to section 5.1), the rest dependencies are straightforward. The only exclusion here
is situation when the current output function is switched ìOffî ñ then PV code is set to FlowRate, thus preserving the
valuable data to be delivered with Command #1. To maintain actual Dynamic Variablesí configuration, master have to
use Command #139 in a pair with Command #50, Read Dynamic Variable Assignments.
Changes in Primary/Secondary Variable setting are reflected at the outputs after the command is processed.
Several transitions in Analog Output Function settings require some preliminary actions (i.e. reprogramming of
frequency/pulse output) that are not automatically done by the HART transmitter. In these cases master is noticed about
an action to be held via appropriate Response Code. Refer also to the instrument Operating Manual.