Yokogawa RotaMASS 3-Series - Manual (Page 153)

APPENdIX 5. PId BLOCK
a-53
IM 01R04B05-00E-E 3rd edition July 30, 2010 -00 all Rights Reserved. Copyright © 2005, Rota Yokogawa
A5.12 External-output
Tracking
External tracking is an action of outputting the
value of the remote output tRK_VaL set from
outside the PID block, as illustrated in the figure
below. External tracking is performed when the
block mode is Lo.
tRK_SCaLE
out_SCaLE
tRK_VaL
out
tRK_In_D
Lo mode
PID control
computation result
Fa0504.EPS
to change the block mode to Lo:
(1) Select track Enable in ContRoL_oPtS.
(2) Set tRK_In_D to true.
However, to change the block mode from Man
to Lo, track in Manual must also be specified in
ContRoL_oPtS.
A5.13 Measured-value
Tracking
Measured-value tracking, also referred to as SP-
PV tracking, is an action to equalize the setpoint
SP to the measured value PV when the block
mode (MoDE_BLK.actual) is Man in order to pre-
vent a sudden change in control output from being
caused by a mode change to auto.
While a cascade primary control block is perform-
ing the automatic or cascade control (in the auto
or CaS mode), when the mode of its secondary
control block is changed from CaS to auto, the
cascade connection is opened and the control
action of the primary block stops. the SP of the
primary controller can be equalized to its cascade
input signal CaS_In also in this case.
the settings for measured-value tracking are
made in the parameter ContRoL_oPtS, as
shown in the table below.
A5.13.1 CONTrOL_OPTS
options in
ContRoL_oPtS
Description
this parameter allows BYPaSS to be set.
Equalizes SP to PV when
MoDE_BLK.target is set to Man.
Equalizes SP to PV when
MoDE_BLK.target is set to Rout.
Equalizes SP to PV when
actual is set to Lo or IMan.
Equalizes SP to RCaS_In when MoDE_
BLK.target is set to RCas, and to CaS_In
when MoDE_BLK.target is set to Cas
when the actual mode of the block is IMan,
Lo, Man or Rout.
Set the PID block to a direct acting
controller.
this enables the external tracking function.
the value in tRK_VaL will replace the
value of out if tRK_In_D becomes true
and the target mode is not Man.
this enables tRK_VaL to replace the
value of out when the target mode is Man
and tRK_In_D is true. the actual mode
will then be Lo.
Sets the value of PV in BKCaL_out and
RCaS_out, instead of the value of SP.
Puts the setpoint high/low limits in force in
the Cas or RCas mode.
Disables the high/low limits for out in the
Man mode.
Bypass Enable
SP-PV track
in Man
SP-PV track
in Rout
SP-PV track
in Lo or IMan
SP-PV track
retained
target
Direct acting
track Enable
track in Manual
use PV for
BKCaL_out
obey SP limits
if Cas or RCas
no out limits
in Manual
ta0508.EPS
A5.14 Initialization and
Manual Fallback
(IMAN)
Initialization and manual fallback denotes a set
of actions in which a PID block changes mode to
IMan (initialization and manual) and suspends the
control action. Initialization and manual fallback
takes place automatically as a means of abnor-
mality handling when the following condition is
met:
• the quality component of BKCaL_In.status is
Bad.
- oR -
• the quality component of BKCaL_In.status is
Good (c)
- anD -
the sub-status component of BKCaL_In.status
is FSa, Lo, nI, or IR.
the user cannot manually change the mode to
IMan. a mode transition to IMan occurs only
when the condition above is met.