Rockwell Automation 1771-IL/B , D17716.5.91 ISOLATED ANALOG INPUT Module User Manual
Page 36
Module Configuration
Chapter 4
4-12
Bit/Word Descriptions for the Isolated Analog Input Module
Configuration Block
Note that decimal bits are shown. Octal bits are shown in parentheses.
Word
Decimal Bit
(Octal Bit)
Description
Word 1
Bits 00-15
(00-17)
Input range selections, grouped 2 bits for each channel, allow selection of any
of 7 input voltage or current ranges. See Table 4.A.
Bits 00-07
Digital filter reduces effect of noise on the input. See “Digital Filtering.”
Word 2
Bit 08 (10)
BTW format bit. This bit determines the format for scaling, digital filter
constant, and high and low alarms.
Bit 08 (10) = 0 - Values must be entered in BCD
Bit 08 (10) = 1 - Values must be entered in Two’s Complement Binary
Word 2
Bits 09-10
(11-12)
Data format is used to match format of processor. See Table 4.D.
Bits 11-15
(13-17)
Real time sampling defaults to 50ms if zeroes are entered. See Table 4.E
for other real time sample intervals.
3
Bits 00-07
Minimum sign bits, when set, designate minimum scaling values that are
negative in BCD. Default = 0 - positive.
Word 3
Bits 08-15
(10-17)
Maximum sign bits, when set, designate maximum scaling values that are
negative in BCD. Default = 0 - positive.
Word 4
Bits 00-15
(00-17)
Minimum scaling values for channel 1. Enter in format selected in word 2,
bit 08 (10). Valid entries are between +9999 and -9999 in BCD; -32767 and
+32767 in binary. Default = 0 - no scaling.
Word 5
Bits 00-15
(00-17)
Maximum scaling values for channel 1. Enter in format selected in word 2,
bit 08 (10). Valid entries are between +9999 and -9999; -32767 and +32767
in binary. Default = 0 - no scaling.
Words 6-19
Bits 00-15
(00-17)
Minimum and maximum scaling values for channels 2 through 8. Enter in
format selected in word 2, bit 08 (10). Valid entries are between +9999 and
-9999; -32767 and +32767 in binary. Default = 0 - no scaling.
2
Bits 00-07
Low alarm sign bits. These bits are only used when BCD format is
chosen in word 2, bit 08 (10). When a bit is set (1), the low alarm value for
that channel is negative. Default is bit reset (0), positive.
Word 20
Bits 08-15
(10-17)
High alarm sign bits. These bits are only used when BCD format is
chosen in word 2, bit 08 (10). When a bit is set (1), the high alarm value for
that channel is negative. Default is bit reset (0), positive.
Word 21
Bits 00-15
(00-17)
Low alarm value for channel 1. This represents the value at which the low
alarm bit for channel 1 (word 13 of the BTR) will be set.
Word 22
Bits 00-15
(00-17)
High alarm value for channel 1. This represents the value at which the high
alarm bit for channel 1 (word 14 of the BTR) will be set.
Words 23
thru 36
Bits 00-15
(00-17)
Low and high alarm values for channels 2 thru 8.