ALTUS Nexto Series User Manual

5. CONFIGURATION
5.12.3. PID Function Block
ATTENTION
The PID function block described up to previous revision L of this manual became obsolete
and was removed from this manual.
The PID, PID_INT and PID_REAL function blocks described up to revision C of
MP399609, also became obsolete and were also removed from newer versions of that man-
ual. Users that need description of these obsolete function blocks due to maintenance reasons
must use revision C of MP399609.
Function blocks PID, PID_INT and PID_REAL must not be used in new projects. These
function blocks were replaced by newer function blocks with additional resources, like auto-
tuning and support to cascade, override and feed-forward controls. These new function
blocks are described in MU214610, and are available after version 1.1.0.0 of library Nex-
toPID.
5.12.4. Timer Retain
The timer retain is a function block developed for applications as production line clocks, that need to store its value and
restart the counting from the same point in case of power supply failure. The values stored by the function block, are only zero
in case of a Reset Cold, Reset Origin or a new application Download (see the MasterTool IEC XE User Manual - MU299609),
when the counters keep working, even when the application is stopped (Stop Mode).
ATTENTION
It is important to stress that, for the correct functioning of the Timer Retain blocks, the
variables must be declared as Retain (VAR RETAIN). It’s also important to notice that in
simulation mode, the Timer Retain function blocks do not run properly due to need the
Nexto CPU for correct behavior.
The three blocks already available in the MasterTool IEC XE software NextoStandard library are described below (for the
library insertion proceeding, see MasterTool IEC XE Programming Manual – MP399609, section Library).
5.12.4.1. TOF_RET
The function block TOF_RET implements a time delay to disable an output. When the input IN has its state changed from
(TRUE) to (FALSE), or a falling edge, the specified time PT will be counted and the Q output will be driven to (FALSE) at the
end of it. When the input IN is in logic level 1 (TRUE), the output Q remain in the same state (TRUE), even if this happened
in the middle of the counting process. The PT time can be changed during the counting as the block assumes the new value if
the counting hasn’t finished. Figure 150 depicts the TOF_RET block and Figure 151 shows its graphic behavior.
Figure 150: TOF_RET Block
Input parameters Type Description
IN BOOL
This variable, when receives a falling edge,
enables the block counting.
PT TIME
This variable specifies the block counting
limit (time delay).
Table 191: TOF_RET Input Parameters
254

ALTUS Nexto Series Specifications

General

Brand	ALTUS
Model	Nexto Series
Category	Computer Hardware
Language	English