Spectrum Controls 1794sc-IRT8I - Manual (Page 39)

Chapter 3: Configuring the 1794sc-IRT8I for ControlLogix/CompactLogix 3-13
User's Manual Pub. 0300242‐01 Rev. A
deadband.
If any of these rules are violated, a configuration error is declared, and the alarm is
disabled. The notable exception is when the “low” is equal to the “high” and both are set
to zero. In this case, user alarms are disabled, the deadband is ignored, and no fault is
declared.
Note: The data range is determined by the data format selected.
The alarm deadband allows the user to define hysteresis for alarms. The alarm set
threshold may differ from the alarm clear threshold, depending on the deadband, as
illustrated below. A value must transition through the indicated threshold (see dashed
arrows) to have the indicated effect.
If a CJC format is selected, the alarm limits apply to that CJC format, not to that
channel’s analog input.
Section 3.5
Read Input
& Status Data
Input and status data is read for each channel, converted to a scaled digital value, and
stored in the controller tags. The following figure describes the tag structure allocated by
the Generic Flex Module profile.
[Name of remote communication module]:e:x.Data[0 to 184]
e = IRT8I slot number
x = Image Type (i.e. C, I, or O)
Using the remote Ethernet adapter example, the input/status tags would appear under the
controller tags as shown in the figure below.
Normal Dead Band Dead Band High Alarm Low Alarm
Low Alarm Threshold (Set)
Low Alarm Threshold + deadband
(Clear)
High Alarm Threshold – deadband
(Clear)
High Alarm Threshold (Set)
Figure 3-3 (Alarm DeadBand)