Rockwell Automation 1771-IL/B , D17716.5.91 ISOLATED ANALOG INPUT Module - Manual (Page 48)

Troubleshooting
Chapter 7
7-3
Table 7.B
Status Reported in Word 1
Word
Decimal Bit
(Octal Bit)
Description
Bit 00
Power up bit (PU) is set after initial power up. It will not reset until the
module receives a valid write block transfer.
Note: Input data is set to zero until the first BTW is received.
Bit 01
Out of range bit (OR) is set if one or more channels are either over or
under range.
Bit 02
Invalid scaling bit (IS) is set if the firmware cannot use the scaling
data in the BTW. Acceptable values are between -9999 and +9999 in
BCD, and -32767 to +32767 in binary.
Word 1
Bit 03
Real time sample (RTS) time out bit is set if the module is using RTS
and a block transfer read has not occurred within the programmed
RTS period.
Bit 04
Invalid Filter bit (IF) is set if the filter parameters are not correct. The
value must be between 00 and 99 (0.00 and 0.99 seconds) in
BCD; or 0 and 255 (0 to 2.55) in binary.
Bit 05
Invalid Alarm bit (IA) is set if any alarm value is unusable, such as
expecting BCD and value is in 2’s complement binary.
Bit 06
Hardware Failure bit (HF) is set if the analog module has an internal
hardware failure (such as blown fuse, etc.).
Bit 07 Alarm bit (A) is set if there is an alarm indication on any channel.
Status Reported in Words 2 and 3
Design your program to monitor over/under range bits, and to take appropriate
action depending on your application requirements. You may also want to
monitor these bits while troubleshooting with your industrial terminal.
Bits 00-07 each represent an input for channels 1-8, respectively. For example,
bit 04 represents input channel 5. The module sets a bit (1) to indicate it has
detected an out of range condition. Refer to Table 7.C.
Table 7.C
Status Reported in Words 2 and 3
Word
Decimal Bit
(Octal Bit)
Description
Word 2 Bits 00-07
Individual underrange bits for each channel. Bit 00 for channel 1, bit 01 for channel
2, etc.. If input connections and voltages are correct, this status may indicate failed
channel communications with the microprocessor. If all channels are underrange,
this indicates a possible dc/dc converter failure or a blown fuse.
Word 3 Bits 00-07
Inputs overrange. Bit 00 is channel 1, bit 07 is channel 8. If input connections and
voltages are correct, this status may indicate a hardware failure.