User Manual
Chapter
6
61
Module Status and Input Data
In this chapter you will read about:
reading data from your module
input module read block format
Block transfer read programming moves status and data from the input module
to the processor’s data table in one I/O scan (Table 6.A). The processor user
program initiates the request to transfer data from the input module to the
processor.
During normal operation the module transfers up to 12 words to the processor’s
data table file. The words contain module status and input data from each
channel. During normal operation, when a block transfer length of zero (0)
is programmed, the 1771–IXHR will respond with a default length of 12.
Table 6.A
BTR
W
ord Assignments for the 1771-IXHR Input Module
Decimal
Bit
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
1 Not used Status Codes
2 Inputs overrange Inputs underrange
3 Inputs > high alarm Inputs < low alarms
4 Channel 1 input
5 Channel 2 input
6 Channel 3 input
::
11 Channel 8 input
12 Cold Junction Temperature in
o
C or
o
F
1
13 Inhibits Auto-calibration request
1
= Cold junction temperature is provided in 0.1
o
C or 0.1
o
F resolution. The filter time constant (Tau) for
this value is fixed at 6.4 seconds.
Chapter Objectives
Reading Data from the Module