KROHNE UFC 500 HART - Manual (Page 10)

HARTô Smart Communications Protocol
UFC500 Command Specification Rev: 2.0 Release Date: 9 Jun 2001
© 2001 KROHNE Mefltechnik D-47058 Duisburg Page 10
5. General Transmitter Information
5.1 Inputs/Outputs And Dynamic/Transmitter Variables
The UFC500 instrument has one current output and one frequency/pulse output.
The UFC500 transmitter handles seven measurement-related variables, hence Transmitter Variablesí set is composed
from variables with indices:
0 - FlowRate
1 - PositiveTotalizer
2 - NegativeTotalizer
3 - Totalizersí Sum
4 - TransitTime
5 - Direction/ErrorIndication
6 - Off.
Any variable except totalizer-related ones (with indices 1..3) can be mapped onto any of the two outputs. To keep
Primary Variable always meaningful/informative it is set to FlowRate in case the function of current output is switched
ìOffî. Therefore the Primary Variable codes belong to subset {0, 4, 5}, whilst Secondary Variable codes - to subset
{0, 4, 5, 6}. Tertiary and Fourth Variables are mapped onto logical slots (no more outputs) and are fixed to
PositiveTotalizer and NegativeTotalizer correspondingly.
5.2 Damping Implementation
The UFC500 transmitter implements the following scheme of analog/digital damping:
•
When the FlowRate Transmitter Variable is a Primary one, both digital/analog dampings are the same and are
handled via Command #34, Write Primary Variable Damping Value.
•
When the current output is not related to flowrate measurements, it has no damping. Still the Command #34
immediately affects the FlowRate damping. After the FlowRate becomes a Primary variable, the current output will
be damped with the same damping as digital variable.
•
TransitTime Transmitter Variable has no damping. When it is mapped onto any output, the latter is not damped.
•
Totalizer-related Transmitted Variables have all only digital presentation and one and the same damping: either 40
msec or the damping value of FlowRate. It depends on the value of FreqPulseDampingControl variable (refer to
Command #132).
•
When the FlowRate variable is a Secondary one (i.e. is mapped onto frequency/pulse output), the output uses either
flowrate measurements damped with 40 msec, or FlowRate damping value. It depends on the value of
FreqPulseDampingControl variable (refer to Command #132).
5.3 Nonvolatile Memory Data Storage
The Flags Byte of Command #0 will have Bit #1 (Command #39, EEPROM Control) set to 0, indicating that all data
sent to the transmitter will be saved automatically in the device EEPROM upon receipt of the Write command or
Command-type command #36. Command #39, EEPROM Control, is not implemented.
5.4 Multidrop Mode
This revision of the UFC500 does not support Multidrop Mode.
5.5 Burst Mode
This revision of the UFC500 does not support Burst Mode.