UT_MODE_SELECT — Off / Hand / Auto / Out of service
UT_MODE_SELECT — Off / Hand / Auto / Out of service
The mode logic every device block uses, and usable on its own for anything that
needs a mode. The HMI mode starts at Off and is retained. After a power cut
it comes back as PowerUp says: as it was (the default), or Off.
Pins
| Pin | Type | Default | What to wire | |
|---|---|---|---|---|
| in | Source |
UT_MODE_SOURCE | UT_SRC_HMI | UT_SRC_HMI · UT_SRC_SWITCH · UT_SRC_REMOTE |
| in | SwHand / SwAuto |
BOOL | FALSE | Selector switch contacts |
| in | AllowOOS |
BOOL | TRUE | FALSE: code 3 (out of service) is not offered |
| in | PowerUp |
UT_POWERUP | UT_PU_LAST | What the mode does after a power cut or a PLC stop / start (below). A device block passes its record's powerUp here |
| in | ForceOff |
BOOL | FALSE | TRUE holds the mode at Off, in every source. The choice underneath is kept and comes back when it drops |
| out | Mode |
UT_MODE | The mode now | |
| out | EnteredOff |
BOOL | One scan: just changed to Off (reset-by-Off uses this) | |
| out | Changed |
BOOL | One scan: the mode just changed | |
| out | HmiChoice |
UT_MODE | The HMI's choice (what CmdMode last selected), whatever the source and ForceOff |
|
| out | HeldOff |
BOOL | Mode is Off because of ForceOff, or because a selector is waiting to be moved after power-up |
|
| inout | CmdMode |
INT | HMI request: 0 Off · 1 Hand · 2 Auto · 3 OOS. Set back to −1 |
How it works
| Source | Mode |
|---|---|
UT_SRC_HMI |
The HMI's choice (retained) |
UT_SRC_SWITCH |
The selector: Hand, Auto, neither = Off, both made = Off |
UT_SRC_REMOTE |
Selector Off and Hand act locally; selector Auto hands control to the HMI's choice |
CmdMode acts once, when a new value arrives: when it differs from the value
read the scan before. The block then sets it back to −1 ("no request"). A value
held there (a debugger force, a master that rewrites it) acts once. Any other code
that is not a mode (4 and up, a negative number, or 3 while AllowOOS is FALSE)
is ignored and set back to −1. If two masters (a panel HMI and SCADA) both change
the mode, put UT_CMD in front.
Power-up (a power cut, or a PLC stop / start):
PowerUp |
HMI mode | Selector found in Hand or Auto |
|---|---|---|
UT_PU_LAST (default) |
Comes back as it was left, from the first scan | Acts at once |
UT_PU_OFF |
Back to Off: the operator selects it again | Held at Off (HeldOff) until it is moved. With UT_SRC_REMOTE only a selector in Hand is held; its Auto position hands over to the HMI, which is Off |
UT_PU_LAST suits an unattended pump that must carry on after a power cut;
UT_PU_OFF suits plant that someone must restart on purpose (a quarry conveyor).
A motor in Hand needs a fresh start press after a power cut in either case (the
motor blocks never keep a Hand start).
ForceOff holds the mode at Off while it is TRUE: a plant-wide off, a
maintenance isolator's auxiliary contact. EnteredOff and reset-by-Off work as for
any change to Off. The HMI's choice is still accepted and kept (HmiChoice) and
takes effect when ForceOff drops.
There is no local / remote lock on CmdMode here: this block can't tell which
master wrote it. Local / remote belongs in UT_CMD (which knows the
source) or in the selector with UT_SRC_REMOTE.