Chapter 3 Malfunctions Not Indicated By A Fault; General; Logic Control Malfunctions - Allen-Bradley 1395 Troubleshooting Manual

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General

Logic Control Malfunctions

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Malfunctions Not Indicated by a Fault
Some drive malfunctions or operating difficulties do not induce drive fault
responses. In some cases the drive is simply not doing what the user desires
and a general guide to help determine what is required for the desired
response is given here. Each section below will deal with either the function
block that is causing the malfunction or in some cases the board related
circuits that may effect the desired response.
The Logic control function block is used to command the drive to perform
various operations. These include Start, Stop, Jog, etc. The "Logic
Command" parameters 150, 151, and 152 are the configuration sink
parameters where the commands are specified. The logic bit assignments
for all logic commands are identical. Each of these logic command
parameters has an assigned order of priority.
Parameter 152 has the highest priority. If Command Enable (Bit 8) is set all
other logic command parameters are overridden. An exception is the STOP
request (Bit 11) which is always active in every logic parameter at all times.
Parameter 152 is the logic command linked to the Bulletin 1300
Programming Terminal and is used when the programming terminal has
LOCAL Control.
Parameter 150 is the second highest priority. If bit 8 in parameter 152 is
clear and bit 8 is set in parameter 150, then parameter 150 issues the logic
commands. If bit 8 of parameters 152 and 150 are clear then control reverts
to the lowest priority logic command, parameter 151, regardless of the
status of bit 8 in parameter 151. Parameter 150 and 151 can be linked to any
adapter's source configuration parameters. It is important to understand
which logic command has control to achieve proper operation.
The 1395 maintains status bits in parameter 100 "Logic Status" which
indicates which logic command is presently active. Bits 2 and 3 are used to
report which of the logic commands are active.
definitions:
Table 3.A Parameter 100 Bit Status Definitions
Bit 3 Bit 2 Definition
0 1 Parameter 150 "Logic Command 1" Active
1 0 Parameter 151 "Logic Command 2" Active
1 1 Parameter 152 "Logic Command 3" Active
A list of logic control malfunctions, symptoms, and possible causes and
solutions is provided in the following table.
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Chapter
Table 3.A lists the bit
3