Rockwell Automation 1771-N SERIES High Resolution Analog Module User Manual - Manual (Page 46)

4–6 Configuring the Module
Publication 1771ĆUM127B-EN-P - December 2002
In the RTS mode, the module scans and updates its inputs at a user
defined time interval (
∆ T) instead of the default interval. The
module ignores block transfer read (BTR) requests for data until the
sample time period elapses. The BTR of
a particular data set
occurs only once at the end of the sample period and subsequent
requests for transferred data are ignored by the module until a new
data set is available. If a BTR does not occur before the end of the
next RTS period, a time-out bit is set in the BTR status area (word
1). When set, this bit indicates that at least one data set was not
transferred to the processor. (The actual number of data sets missed
is unknown.) The time-out bit is reset at the completion of the BTR.
Legal RTS values are in intervals of 1ms from 0.100 to 10.000
seconds in binary format, or 0.100 to 9.999 seconds in BCD format.
An RTS value of 0 disables the real time sampling feature.
Output channel programming features include:
• low and high scaling
• low and high clamping
• ramping
• alarm enable
• reset state
• reset value
Scaling
Scaling is the conversion of unscaled data to engineering units. You
use scaling so that the data for each channel is represented in actual
engineering units.
Each channel has two scaling points, low and high. The signal value
at these points is fixed. For example, the high scaling point of a
+10V output channel always corresponds to an output signal equal to
+10.000V.
Output Channel
Programming Features