Rockwell Automation 1771-IFE ANALOG INPUT MODULE - Manual (Page 44)

5–2 Module Status and Input Data
Publication 1771Ć6.5.115 - February 1999
The bit/word description for the block transfer read of the Analog
Input Module is described below.
Table 5.A
BTR Word Format for the Analog Input Module
Word Decimal Bit
(Octal Bit)
Description
Word 1
Bit 00
Power up bit (PU) - Used by the module to tell the processor that it is
alive but not yet configured. It is a key element in the application
program.
Bit 01
Out of range bit (OR) - This bit is sent to tell the processor that one
or more channels are either over or under range. 1
Bit 02
Invalid scaling bit (IS) - This bit reports that the scaling is somehow
invalid. Usually, both values are equal or minimum is greater than
maximum when this bit comes on. Can also be an invalid filter value.
Bit 03
Real time sample fault bit (RTS) - This bit is set if the module is
configured for RTS and a block transfer read has not occurred within
the user-programmed period.
Bit 04
Calibration status bit (CS) - When calibrating the module, this bit will
be cleared if the calibration was successful. If the bit is set, an
incorrect voltage/current was applied, or offset and gain calibrations
were attempted simultaneously.
Bit 05
EEPROM status bit (EE) - This bit is set if an error occurs saving
calibration data to nonvolatile memory. If this bit is set at powerup, the
data from the EEPROM did not pass the checksum and no calibration
values are used.
Bit 06
Hardware fault (HF) - When this bit is set, the dc/dc converter fuse
has blown. Digital logic will continue to operate.
Bits 07-15
(07-17)
Not used.
Word 2
Bits 00-15
(00-17)
Underrange bits for each channel. Bit 00 for channel 1, bit 01 for
channel 2, etc. 1 These bits are set (1) at approximately the input
range limits selected from Table 5.B.
Word 3
Bits 00-15
(00-17)
Overrange bits for each channel. Bit 00 for channel 1, bit 01 for
channel 2, etc. 1 These bits are set (1) at approximately the input
range limits selected from Table 5.B.
Word 4 Bits 00-15
(00-17)
Polarity bits - Set when input is less than zero. Bit 00 for channel 1,
bit 01 for channel 2, etc.
Word 5 thru 20 Input values - Word 5 for channel 1, word 6 for channel 2, etc.
Word 21 Bits 00-15
(00-17)
Offset calibration results bits - Each bit represents a channel. After
a calibration BTW has been sent, the module confirms calibration by
echoing back the channels that were calibrated during the offset
calibration BTW. In differential mode, channels 09 thru 16 are zero.
Word 22 Bits 00-15
(00-17)
Gain calibration results bits - Each bit represents a channel. After a
calibration BTW has been sent, the module confirms calibration by
echoing back the channels that were calibrated during the gain
calibration BTW. In differential mode, channels 09 thru 16 are zero.
1 Attention: If an input terminal's voltage exceeds +14.25V as referenced to module common, channelĆtoĆchannel crosstalk can
cause invalid input readings and invalid underrange/overrange bits.
Block Transfer Read
Format