Chart Scale - Omega RD8800 User Manual

Chapter 5 Programming
g. True or False Alarm Types
NOTE: True and False Alarm Types are available for Conditional Point types ONLY.
True and False Alarm conditions become active when a Boolean expression is True or False
respectively. No set point is required.
To set a True or False Alarm Type:
Use the UP (↑ ↑ ↑ ↑ ↑ ) or DOWN (↓ ↓ ↓ ↓ ↓ ) button to highlight Type=true or Type=false as desired and press
the ENTER button. You will be prompted with "contact #? X". This is the contact output that will
respond to this alarm provided the relay option is fitted. If no contact output is required, select
contact # 0. Use the UP (↑ ↑ ↑ ↑ ↑ ) or DOWN (↓ ↓ ↓ ↓ ↓ ) button to select the desired contact number (0 to 6) and
press the ENTER button. The display will return to the Alarm Type menu. Press the EXIT button
to return to the Alarms Setup menu.
5.6.5.10.2 Alarm deadband
An Alarm deadband can be set for each alarm set. The Alarm deadband is also called hysteresis and
is an amount added or subtracted (depending whether the Alarm is Low or High) to the actual set point
to determine the reset point. It is primarily intended to reject noise about a set point. For example,
if a High Alarm set point is at 50 and the deadband is set at 5, the Alarm will trigger when the input
exceeds 50 but will not clear (reset) until the input reaches 45 (set point minus hysteresis).
To set the Alarm deadband (hysteresis):
From the Alarms Setup menu use the UP (↑ ↑ ↑ ↑ ↑ ) or DOWN (↓ ↓ ↓ ↓ ↓ ) button to highlight Alm deadband and press
the ENTER button. You will be prompted with "db
desired deadband value in absolute Engineering units and press the ENTER button. The display will
return to the Alarms Setup menu.
5.6.5.10.3 Alarm delay
An Alarm delay can be set for each alarm set. This delay prevents the Alarms from activating until the
set time has elapsed from an Alarm active condition. If the Alarm condition goes away before the delay
is up, the Alarm will not respond. The delay retriggers. If the Alarm condition goes away before the
delay is up and then returns, the delay is reset and the full delay period will expire before the Alarm
becomes active. This feature can be used to overcome spurious or transient Alarm conditions.
To set the Alarm delay:
From the Alarms Setup menu use the UP (↑ ↑ ↑ ↑ ↑ ) or DOWN (↓ ↓ ↓ ↓ ↓ ) button to highlight Alm delay and press the
ENTER button. You will be prompted with "seconds XXXX ". Use the numeric keypad to enter the
desired delay, up to a maximum of 600 seconds (ten minutes), and press the ENTER button. The display
will return to the Alarms Setup Menu.

5.6.5.11 Chart scale

Each point must be assigned to a Chart scale. The Chart scale is used to control the display of the output
signal and can be used to display or record only part of the output, the area of interest, or across the entire
range. There are two sets of eight Chart scales available. A Chart scale can be assigned to multiple points.
To set the Chart scale:
From the Point Setup menu use the UP (↑ ↑ ↑ ↑ ↑ ) or DOWN (↓ ↓ ↓ ↓ ↓ ) button to highlight Chart scale and press the
ENTER button. You will be prompted with "chart scl= X". Use the UP (↑ ↑ ↑ ↑ ↑ ) or DOWN (↓ ↓ ↓ ↓ ↓ ) button to select the
desired Chart scale numeral (A through H) and press the ENTER button. The display will return to the Point
Setup menu.
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X.XXX ". Use the numeric keypad to enter the
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