Operating Manual

Accu-Wave Chapter 6 Cuurent Outputs, Relays, and Alarms
TN Technologies 6-1
Chapter 6 Current Outputs, Relays, and Alarms
This chapter covers the “Modify or reassign current output” menu (the “Current output”
menu) and the “Set up fault alarms or change process alarm assignments” menu (the
“Alarm” menu).
Current Outputs
Note: If your MeasureTech Accu-Wave does not have an I/O board with a current
output installed, the “Modify or reassign current output” menu will not be
displayed.
Use the “Current outputs” menu to
• specify which measurement should drive the current output
• implement correction factors on each current output
• define a current output hold value which is different from the default of 50% of
scale
Note: Measurements other than the primary measurement (level or distance)
must be set up in the “Set up additional measurements” menu (see
Chapter 4) before they can control a current output.
You can direct different measurements to the same current output, but one must be
assigned in normal output mode and the other must be in alternate output mode. The
current output can be switched from normal mode to alternate mode by executing a
command to switch when an alarm is triggered (see “Set up for Alarms to Execute
Commands” on page 6-4) or you can enter a command to switch modes (see “Common
Action Items” on page 7-2).
For example, if you were interested in monitoring a maximum level of 20 ft during one
portion of the process and a maximum level of 10 ft during another part of the process,
you could set up the measurements and current outputs as follows.
Set up measurement 1 (the primary measurement) as level and assign it to drive the current
output in normal mode with the maximum current output corresponding to 20 ft.
Also assign measurement 2 to the level measurement, but assign measurement 2 to drive
the current output in alternate mode with the maximum current output corresponding to 10
ft. Recall that the measurement value corresponding to the maximum current output is
entered in the measurement setup menus.
Note: It is good practice to make a list of the current output assignments as you
set them up, and keep the list available for future reference.