KROHNE UFC 500 HART - Manual (Page 45)

HARTô Smart Communications Protocol
UFC500 Command Specification Rev: 2.0 Release Date: 9 Jun 2001
© 2001 KROHNE Mefltechnik D-47058 Duisburg Page 45
8.24 Command #158 Read Transmitter Variable Range Values
Reads the Upper/Lower Range Values of the Transmitter Variable. This command was introduced (instead of the
support of Common-Practice Command #63, Read Analog Output Information) solely to resolve ambiguous situation
when one and the same Transmitter Variable, namely FlowRate, has two pairs of Upper/Lower Range Values - for
forward and reverse flow. Therefore Transmitter Variable set (refer to section 5.1) was augmented by a dummy variable
ReverseFlow with index 10.
REQUEST DATA BYTES
#0
XMTR
VAR
CODE
RESPONSE DATA BYTES
#0 #1
XMTR XMTR
VAR VAR
CODE RANGE
UNITS
#2 #3 #4 #5
XMTR XMTR
VAR VAR
URV URV
MSB LSB
#6 #7 #8 #9
XMTR XMTR
VAR VAR
LRV LRV
MSB LSB
Data Byte #0 Transmitter Variable Code:
0 - FlowRate,
4 - TransitTime,
10 - ReverseFlow.
The ReverseFlow assignment is meaningful only for this and subsequent command (of Write
type). The FlowRate value of TV Code will evoke response for forward flow.
Data Byte #1 The range units of the corresponding Transmitter Variable. For a set of supported flowrate
units refer to the Table 9.1. Note that the ranges of FlowRate and ReverseFlow might have
different units.
For TransitTime Transmitter Variable the manufacturer-specific units are used: 246, ì
µ
secî.
Data Byte #2-#5 Transmitter Variable Upper Range Value, IEEE 754, in the RangeUnits.
Data Byte #6-#9 Transmitter Variable Lower Range Value, IEEE 754, in the RangeUnits.
NOTE: For the ReverseFlow the Range values are meaningful only when the ReverseScaleControl (refer to Command
#156) is set to zero (ìDifferentî) and the function of any output is set to either ìForward/reverse flowî or to ì2 Dirî
(refer to Command #138).