SMAR ld301, Operation And Maintenance Instruction Manual

Page: 21 / 70

Section 3
3.1
Configuration
The LD301 Intelligent Pressure Transmitter is a digital instrument with the most up-to-
date features a measurement device can possibly have. Its digital communication
protocol (HART

) enables the instrument to be connected to a computer in order to be
configured in a very simple and complete way. Such computers connected to the
transmitters are called HOST computers. They can either be Primary or Secondary
Masters. Therefore, even the HART

being a master-slave type of protocol, it is possible
to work with up to two masters in a bus. The Primary HOST plays the supervisory role
and the Secondary HOST plays the Configurator role.
The transmitters may be connected in a point-to-point or multidrop type network. In a
point-to-point connection, the equipment must be in its "0" address so that the output
current may be modulated in 4 to 20 mA, as per the measurement. In a multidrop
network, if the devices are recognized by their addresses, the transmitters shall be
configured with a network address between "1" and "15. In this case, the transmitters
output current is kept constant, with a consumption of 4 mA each. If the
acknowledgement mechanism is via Tag, the transmitters addresses may be "0" while,
their output current is still being controlled, even in a multidrop configuration.
In the case of the LD301 , which can be configured both as Transmitter as a Controller;
the HART

addressing is used as follows:
TRANSMITTER MODE - The "0" address causes the LD301 to control its output current
and addresses "1" through "15" place the LD301 in the multidrop mode with current
control.
CONTROLLER MODE - The LD301 always controls the output current, in accordance
with the value calculated for the Controlled Variable, regardless of its network address.
NOTA
In the case of multidrop network configuration for classified areas, the entity
parameters allowed for the area shall be strictly observed. Therefore, the following
shall be checked:
Ca ≥ Σ Ci
j
+ Cc La ≥ Σ Li
j
+ Lc
Voc
≤
min [Vmax
j
] Isc
≤
min [Imax
j
]
Where:
Ca, La - Barrier Allowable Capacitance and Inductance
Ci
j
, Li
j
- Non protected internal Capacitance/Inductance of transmitter j (j = up to 15)
Cc , Lc - Cable capacitance and Inductance
V
oc
- Barrier open circuit voltage
I
sc
- Barrier short circuit current
Vmax
j
- Maximum allowable voltage to be applied to the instrument j
Imax
j
- Maximum allowable current to be applied to the instrument j
The LD301 Intelligent Pressure Transmitter includes a very encompassing set of
HART

Command functions that make it possible to access the functionality of what has
been implemented. Such commands comply with the HART

protocol specifications,
and are grouped as Overall Commands, Common Practice Controls Commands and
Specific Commands. A detailed description of such commands may be found in the
manual entitled HART

Command Specification - LD301 Intelligent Pressure
Transmitter.
Smar developed two types of Configurators for its HART

devices: HT2 Configurator
(old) and HPC301 Configurator (current). The HT2 Configurator uses the PSION pocket
computer platform and the HPC301 uses the up-to-date technology of Palm Vx
Handheld computers. The operational details of each configurator are described on their
specific manuals.
Figure 3.1 shows the front of each type of each Smar Configurator.