Technical Specifications

Masoneilan Valves ValVue ESD Instruction Manual =| 65
© 2014 General Electric Company. All rights reserved.
Preamble Count A device using the HART protocol sends a short string of characters
at the beginning of each communication to wake up the other
device. This string is called a preamble. The number of preambles
prefixed to each Hart command sent to a device varies from device
to device. The valid range is 2 to 20. Recommended values for this
parameter are 3 to 5 when using the Mux. ValVue ESD allows for a
user-configured Mux preamble count.
Scan Age Time The length of time in seconds that scan data remains valid. An error
is returned when the scan data requested is older than the time
when the data was last updated. This parameter set s this time for
other applications that use the multiplexor. ValVue ESD does not
support the scanning feature.
Multiplexor Master Mode ValVue ESD Options must be set to use the same mode as the multi-
plexor. Other applications that use the multiplexor or other HART
masters can require a special selection. See the multiplexor docu-
mentation for further information.
Search Method When building a device list, the multiplexor can use one of three
methods:
 Polling Address 0 only - This method looks only at polling
address 0 for each loop. Any devices on a loop with a
non-zero polling address are not found.
 One Device - For each loop, all polling addresses are searched
until a device is found. The multiplexor does not continue the
search on a loop after the first device is found.
 Multidrop - For each loop, polling address 0 is checked. If a
device is found, no further search is performed on that loop. If
no device is found at polling address 0, polling addresses 1 -
15 are searched and any devices found are added to the
device list.
Mux Reset
Select Mux Reset to issue a reset command to a node of the multiplexor. This function is
enabled and used only in the multiplexor configuration of the program. You are prompted for
the node that is to be reset. When reset, the multiplexor node re-scans all of the devices
connected to it and depending on the multiplexor options set for the multiplexor, can take
some time to complete. If hardware has been added to the Mux or connected to different Mux
channels a rescan must be performed before the ValVue ESD re-scan can be used.
The Mux Reset is necessary when adding or removing HART devices on a Mux network. This
function updates the Mux’s Look Up Table utilized by ValVue ESD to map devices.