R 02/92
Programming Instructions
9.5.14 Process Alarm Processing
The interrupt processing for this example is programmed in organization block062.
Depending on the type of programmable controller used, the process interrupts are acquired via
the
input
byte
160
(with
S5–150U/S,
S5–155U
in
S5–150U
mode) or via an interrupt
line
(with
S5–115U, S5–135U, and S5–155U in S5–155U mode).
At the start of an interrupt block, the scratchpad flags must be saved and reloaded prior to leaving
the block. With the S5– 155U this is accomplished with the standard function blocks FB 38 and FB
39. These function blocks are part of the standard function block package “basic functions”.
Saving and reloading of the scratchpad flags must be performed for all types of
interrupt–con-
trolled program processing (also in the organization blocks for restart and error evaluation). In
each case a different data area must be used. (This is taken into consideration in the example.)
Exception PLCS5-155U:
Function blocks FB 38 and FB 39 establish a stack in the data block, where the status of the
scratchpad flags and some system data words are stored. (Also stored are the system data
RS
60
to
RS
63, enabled for the user.) The data block can be set up to data wordDW816. Function blocks
FB 38 and FB 39 must be used in pairs under all circumstances (i.e., an organization block pro-
grammed with these blocks may not be left prematurely with the conditional block end
BEC).
In interrupt processing organization block062, function block FB 12 (call FB 158) is activated for
indirect
parameterization
and program block PB 12 (call FB 157) for direct
parameterization.
The
track identifier bits are updated in both blocks with the “KB” command. Input bit 15.6 can be used
to choose between indirect (1 5.6 = “O”) and direct
parameterization
(1 5.6 = “1 “).
Interrupt for end setpoint of track 4
The end
setpoint
of track 4 is supplied with an interrupt identifier. For this purpose the value of the
right data byte
DR
30 in user data block
DB
156 must be other than zero. This can be performed
with the programmer function “control variable”. After
parameterization
via input 14.4, the screen
display appears as follows:
Direct
parameterization
(PB 12)
FD 134 KH – 00000572
(Actual value)
FW 132
KM – 0000000000000000
(Track identifier bits)
FD 138
KH – 00000250
(Initial
setpoint
track 4)
FD 142
KH – 00400350
(End
setpoint
track 4)
9 – 57
1P
241 Equipment Manual
@.SiemensA(31989, Order No.: 6ES5998-0KD21
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