Thermo Scientific AutoXP, Руководство пользователя, Страница: 39 / 131

Thermo Fisher Scientific
4-3 AutoXP Users Guide
HART
4-20mA Output
The 4-20ma output represents the digital Primary Variable [PV].
For AutoXP the PV can be setup for Differential Pressure, Static Pressure or Line
Temperature.
By default, the 4-20mA output is set for Differential Pressure with a Range of 0-100
inches H2O. This can be modified to suit customer requirements using a HART
master such as a 475 HHT or AMS PC based system.
4-20
mA Damping
Current Loop range
HART Masters
If required, the 4-20mA output can have a damping value applied to smooth out any
sudden changes on the current loop.
Damping is entered as an integer representing seconds.
The output will then reply to a step change and the output will achieve 66% of
final value after the number of seconds entered.
For example, if five seconds is entered, the output will ramp up to the final
step change value such that after 5 seconds the output represents 66% of the
final value.
If no damping is required, PV Damping can be set to zeros (0s – the default setting).
The current loop for the AutoXP has an operating range of 3.8
–
20.8mA.
This allows for an over and under-range of the Primary Variable on the current
loop.
Configuration and interrogation of the AutoXP MVT via the HART
protocol can be accomplished using either a Primary and/or Secondary
HART Master.
Primary masters can be host systems, such as AMS or SIMATIC PDM. Secondary
masters are generally those such as an Emerson 475 Hand Held Terminal.
With each host, a Device Description Language (DDL) file will be required to
configure/calibrate the AutoXP I/O. The DDL for the AutoXP has been registered
and can be obtained directly from the HART Communication Foundation at
www.fieldcommgroup.org.