Diagnostics and troubleshooting, Read blocktransfer status words – Rockwell Automation 1771-OFE Analog Output Module Installation Instructions User Manual
Page 13
Analog Output Module
13
Publication 1771-IN044C-EN-P - October 2002
The front panel of the module contains a green RUN and a red FLT
(fault) indicator. Possible module fault causes and corrective actions
are shown in the table below.
Indicators
Probable Cause
Recommended Action
RUN (green on)
FLT (red off)
1. Awaiting configuration BTW
2. Normal operation
1. At power-up, the module output is
disabled until the module receives the
first BTW. The output is enabled and
goes to the value sent in the BTW
(normal operation).
2. None
RUN (green on)
FLT (red on)
Unsuccessful powerĆup
EEPROM fault
Checksum error
Hardware failure in module
Cycle power
Return module for repair
RUN (green off)
FLT (red off)
No power
Bad internal fuse
Turn off power.
Remove and reinsert module into
chassis. Return power.
If problem still exists, and chassis power
supply is functioning properly, return the
module for repair.
Read BlockTransfer Status Words
The module allows a five-word read block transfer for rudimentary
program or hardware debugging. If a read block transfer request is
for more or less than five words, the module will not perform a read
block transfer. The following table shows the word assignment for
the read block transfer.
Decimal Bit
15
14
13
12
11
10
09
08
07
06
05
04
03
02
01
00
Octal Bit
17
16
15
14
13
12
11
10
07
06
05
04
03
02
01
00
Word 1
Channel 1 DAC Input Data
2
Channel 2 DAC Input Data
3
Channel 3 DAC Input Data
4
Channel 4 DAC Input Data
5
Not
used
I/O
Reset
Reserved
Data Valid
The first four words of the read block transfer show the actual 12 bits
of data sent to the module’s digital-to-analog converters (DACs).
The first four words in the read block transfer appear in 12-bit binary
format regardless of the module’s mode of operation (BCD or 12-bit
binary).
ANALOG
OUT
(12 BIT)
RUN
FLT
Green RUN
indicator
Red FAULT
indicator
Diagnostics and
Troubleshooting