Rockwell Automation 1798-IB4 FlexArmor User Manual User Manual
Page 25
Publication 1798-UM001B-EN-P - November 2002
How Communication Takes Place and I/O Image Table Mapping 2-11
Word/Bit Descriptions for the 1798-IE4 Analog Input Module Write
Word
Decimal Bit
Definition
Read Word 1
Bits 00-14
Channel 0 analog data - 12-bit left justified two’s
complement number; unused lower bits are zero;
4-20mA uses all 16 bits
Bit15
Channel 0 analog data sign bit
Read Word 2
Bits 00-14
Channel 1 analog data - 12-bit left justified two’s
complement number; unused lower bits are zero;
4-20mA uses all 16 bits
Bit15
Channel 1 analog data sign bit
Read Word 3
Bits 00-14
Channel 2 analog data - 12-bit left justified two’s
complement number; unused lower bits are zero;
4-20mA uses all 16 bits
Bit15
Channel 2 analog data sign bit
Read Word 4
Bits 00-14
Channel 3 analog data - 12-bit left justified two’s
complement number; unused lower bits are zero;
4-20mA uses all 16 bits
Bit15
Channel 3 analog data sign bit
Read Word 5-8
Not Used
Read Word 9
Bits 00-03
Underrange bits (U) for individual channels (4-20mA
current input only) - Bit 00 corresponds to input
channel 0, bit 01 corresponds to input channel 1, and
so on. When set (1), indicates either a broken or open
input wire, or input current below 4-20mA.
Bits 04-14
Not used - set to 0
Bit 15
Power Up bit - This bit is set to 1 when all bits in the
configuration register are 0 (unconfigured state). The
configuration register can be cleared by either of the
reset inputs, or by the user writing all zeroes to it.
Write Word 1
Bits 00-03
Full range bits (F) for individual channels - Bit 00
corresponds to input channel 0, bit 01 corresponds to
input channel 1, and so on. Refer to range selection
above.
Bits 08-11
Configure select bits (C) for individual channels - Bits
08 corresponds to input channel 0, bit 09 corresponds
to input 1, and so on. Refer to range selection above.
Write Word 2-6
Bits 00-15
Not used - set to 0