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Yokogawa Electric Corporation - TC10 - ENGINEERING MANUAL - PAG. 15

[49] HAL3 - Alarm 3 hysteresis

Available:

When [44] AL3t is different to “nonE” or [44] AL3t

is different from “SE.br”.

Range:

1 to 9999 engineering units.

Note:

For other details see [33] HAL1 parameter.

[50] AL3d - Alarm 3 delay

Available:

When [44] AL3t different form “nonE”.

Range:

From oFF (0) to 9999 seconds.

Note:

The alarm goes ON only when the alarm condition

persist for a time longer than [50] AL3d time but the

reset is immediate.

[51] AL3o - Alarm 3 enabling during Stand-by mode

and out of range indications

Available:

When [44] AL3t is different from “nonE” or
[44] AL3t is different from “SE.br”.

Range:

0 =

Never;

1 =

During stand by;

2 =

During overrange and underrange;

3 =

During overrange, underrange and stand-by.

]

LbA group - Loop break alarm

General note about LBA alarm

The LBA operate as follows: applying the 100% of the power
output to a process, the process variable, after a time due to the
process inertia, begins to change in a known direction (increases
for an heating action or decreases for a cooling action).

Example:

If I apply 100% of the power output to a furnace,

the temperature must go up unless one of the component in
the loop is faulty (heater, sensor, power supply, fuse, etc.)
The same philosophy can be applied to the minimum power.
In our example, when I turn OFF the power to a furnace, the
temperature must go down, if not the SSR is in short circuit,
the valve is jammed, etc..
LBA function is automatically enabled when the PID requires
the maximum or the minimum power.
When the process response is slower than the programmed
limit the instrument generates an alarm.

Notes: 1.

When the instrument is in manual mode, the LBA
function is disabled.

When LBA alarm is ON the instrument continues
to perform the standard control. If the process
response comes back into the programmed limit,
the instrument automatically resets the LBA alarm.

This function is available only when the programmed
control algorithm is equal to PID (Cont = PID).

[52] LbAt - LBA time

Available:

When [56] Cont = PID.

Range:

oFF = LBA not used;
1 to 9999 seconds.

[53] LbSt - Delta measure used by LBA during

Soft start

Available:

When [52] LbAt is different from oFF.

Range:

oFF = loop break alarm is inhibit during soft start;
1 to 9999 engineering units.

[54] LbAS - Delta measure used by loop break

alarm (loop break alarm step)

Available:

When [52] LbAt is different from oFF.

Range:

1 to 9999 engineering units.

[55] LbcA - Condition for LBA enabling

Available:

when [52] LbAt is different from oFF.

Range:

uP =

Enabled when the PID requires the maxi-
mum power only;

dn =

Enabled when the PID requires the mini-
mum power only;

both = Enabled in both condition (when the PID re-

quires the maximum or the minimum power).

LBA application example:

LbAt (LBA time) = 120 seconds (2 minutes);

LbAS (delta LBA) = 5°C.

The machine has been designed in order to reach 200°C in
20 minutes (20°C/min);
When the PID demands 100% power, the instrument starts
the time count.
During time count if the measured value increases more
than 5°C, the instrument restarts the time count. Otherwise
if the measured value does not reach the programmed delta
(5°C in 2 minutes) the instrument will generate the alarm.

]

rEG group - Control parameters

The rEG group will be available only when at least one
output is programmed as control output (H.rEG or C.rEG).

[56] cont - Control type:

Available:

When at least one output is programmed as con-
trol output (H.rEG or C.rEG).

Range: •

When two control action (heat & cool) are pro-
grammed:

Pid =

PID (heat and cool);

nr =

Heat/Cool ON/OFF control with neutral zone.