Alarms Registers - Siemens 6ES5-424 Technical Reference Manual

Chapter 4
Standard
Software
In order for the MM register to be set to the correct value, it
4.4.3 Alarms Registers
would be necessary to use the PA function for counter 1 after
The AM 951 counter chip and therefore the 6ES5 242 module
the using the PA for any of the other counters. For example:
are organized in such a manner that only counters 1 and 2
1.
-
PA counter 1; the MM register will be set to 3EH
have alarm registers available to them for use. These registers
2.
-
PA counter 3; the MM register will be set to O O H are used to provide a comparison value, when the compare
function is enabled in the MM register. 3.
-
PA counter 1; the MM register will again be set to 3EH
This is a simple example and it could easily be changed to
operate properly, but this is not the point. The idea of the
example is to show that while using the PA function it is
necessary to make sure that once the MM or the INTM is set,
that it is not changed without the user being aware of the
FBI59 in turn provides an alarm register value for each of the
five counters within the data block. Only the values for
counters 1 and 2 are of any use. The values for counters 3,4,
and 5 are irrelevant. The associated data words within the
data block are listed below.
change.
DW16 Alarm register for Counter 1, active
A solution to this problem would be to write the values for
DW23 Alarm register for Counter 2, active
the MM and INTM registers in each of the data words for the
DW30 Alarm register for Counter 3, irrelevant
five counters. This way the user will not have to be concerned
DW37
register for Counter 4, irrelevant
@
that the MM register or the INTM register values will be changed
DW44 Alarm register for Counter 5, irrelevant
on each PA function call.