Rockwell Automation 57C411 Resolver Input Module - Manual (Page 29)

4Ć11
7025 !
7026 ! The next statement calculates the distance
7027 ! traveled from the occurrence of the external
7028 ! event until this scan.
7029 !
7030 CALL PULSE_MULT( INPUT=RESOLVER_IN%,ăăăă&
RESET=-STROBE_RESET@,ăă&
INITIAL_VALUE =RESOLVER_IN_EXT%, &
MULTIPLIER=16385,ăăăăăăăăă&
OUTPUT=EVENT_DISTANCE%)
7036 ! The next statement calculates the distance traveled
7037 ! from the last scan until this scan.
7039 !
7040 CALL PULSE_MULT( INPUT=RESOLVER_IN%, &
MULTIPLIER=16385, &
OUTPUT=PERIOD_DISTANCE%)
7046 !
7047 ! The next statement calculates the correction
7048 ! required to synchronize the external event to
7049 ! the program.
7050 !
7060 CALL DIFFERENCE( INPUT1=PERIOD_ DISTANCE%, &
INPUT2=EVENT_DISTANCE%, &
OUTPUT=RESOLVER_VALUE%)
10000 END
4.7 Restrictions
This section describes limitations and restrictions on the use of this
module.
4.7.1 Writing Data to Registers
Registers 0Ć2 are read only and may not be written to by the
application software. Attempts to write to them will cause a bus error
(severe system error). The following are examples from programs
that write to the module and should therefore be avoided:
a. Referencing the module on the left side of an equal sign in a LET
statement in a control block or BASIC task.
b. Referencing a resolver input as an output in a control block
function.
4.7.2 Interrupts in Remote I/O Racks
This module cannot be used in the interrupt mode in a remote rack.
4.7.3 Feedback Elementin a Drive System
When this module is used with a resolver in a drive control system,
you must incorporate an independent method of determining that
this module is actually reading proper motor RPM. It is necessary to
determine this because this module is not capable of detecting a loss
of feedback in all situations, such as, for example, a broken coupling
between the motor and resolver.