One option a user must select correctly is which communication serial port the computer uses for the
HART communication channel. Once selected in the Options window, this selection overrides any
selection on the command line that starts the program.
If the Allow Multidrop box in HART Optional is checked, ValVue supports HART devices (including SVIs)
with non-zero polling addresses and supports multiple SVIs on the same loop (for split range applica-
tions). If the box is unchecked, ValVue will look for devices only at polling address 0. When in multidrop
mode, even if a device is found at polling address 0, ValVue searches for devices with other polling
addresses. This allows a loop with a transmitter operating 4-20 mA with polling address 0 and an SVI
operating as a controller and positioner with polling address 1-15.
ValVue running on a PC can send commands to a HART device as a primary master or a secondary
master. The ValVue program must be configured to match the configuration of the multiplexer. That is,
if the multiplexer is a primary master, ValVue must also be configured to be a primary master.
If the option of Hide Background is selected, the ValVue background is hidden. Otherwise, the back-
ground will cover the whole screen.
The device list may be saved in a file in order to eliminate the necessity of re-scanning each time con-
nect is selected. Unless the option of Load Device Addresses from File is selected, the file used is tem-
porary and a re-scan is done each time the program is restarted. If selected, the user may select a file
in which to save the device list. This file will be read whenever the program is started and the saved
device list is displayed. This will save the time required to re-scan and is particularly useful for a multi-
plexer connected to many devices.
In the multiplexer version of the program, the option of Use Multiplexer allows the user to select either
direct connect (through a Hart modem) or multiplexer operation. Check the Use Multiplexer box to
enable the ValVue support of the MTL multiplexer.
The MTL multiplexer supports baud rates of 9600, 19200, and 38400. The user must select the baud
rate at which the hardware has been configured.
After the options are selected, you can click OK to accept the changes and exit to Select Device window
(figure 62). Three multiplexer-related buttons, Add Device, Mux Setup, and Mux Reset are enabled and
appear near the Options button.
102
Figure 62.
Select Device
Window
