gefran 2850T, Инструкция по использованию и установке, Страница: 85 / 166

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4. CONFIGURATION
80703B_MHW_2850T/3850T_02-2019_ENG
The page configuration sequence is specifically in reverse
order because the Base/Alarm/Variable/Synoptic order
reflects the order of importance of parameters when edited
in an existent PID.
4.15.4.2. PID base configuration
The Base section lets you set PID base parameters. To
open the base parameter page, double-click the
Base but-
ton and select Base from the drop-down menu. The Base
page can be opened from other pages in the Base section
by touching key 1 on the left.
The number of the PID to be set is displayed at the top of
the screen and can be changed using the
- and + keys.
Turn the PID on and off with the EN button. The key turns
green when the PID is enabled.
The value can be entered with the virtual keyboard by
touching some parameters.
The available parameters and functions are:
• RATIO : indicates the value of the ratio and is only
displayed if Ratio operations were set in the Synoptic
menu.
• SP : setpoint, value to be reached and maintained.
• PV : process value, current value (read only).
• Group : group of PID parameters used for regulation
chosen from the 10 available. Groups are a permanent
setting, and so if the device is restarted, group 1 will
always be set. Their principal use is in combination
with the programmer, in which the regulation unit can
be chosen for each segment.
• PID / ON-OFF
: touch the key to alternatively enable
automatic regulation (PID) or ON-OFF.
• HEAT : turns the heating function on (green) or off.
• COOL : turns the cooling function on (green) or off.
• CT s : Cycle time, that is, the duration of the digital
output cycle. If set to 0, cycle time is as short as pos-
sible (Burst Firing mode); otherwise, it will be the time
shown in seconds. Available separately for Heat and
Cool functions.
• PB : Proportional band, meaning the proportional band
used for PID regulation. Available separately for Heat
and Cool functions. In the case of ON/OFF control, this
parameter represents hysteresis (HYS)
• IT m : Integral time, meaning the integral time used for
PID regulation. Available separately for Heat and Cool
functions. The parameter is not displayed if manual or
ON-OFF regulation is enabled.
• DT m : Derivative time, meaning the derivative time
used for PID regulation. Available separately for Heat
and Cool functions. The parameter is not displayed if
manual or ON-OFF regulation is enabled.
Note
If you choose Burst Firing management (CT=0.0), digital
outputs will be controlled (with On and Off times of no less
than 100 ms) to distribute dispensation of the required pow-
er as uniformly as possible and in as little time as possible.
If you choose a cycle time other than zero, on the other
hand, control of the On and Off times of digital outputs
will be managed simply to ensure that the ratio with the
selected CT time corresponds to the required power. In this
way, digital outputs may be controlled for times of no less
than 25ms.
If, for example, we wish to deliver power at 50.0% with
CT=0.0, the outputs will be On for 100ms and Off for
100ms. At 75.0% power, they will be 300ms On and 100ms
Off, followed immediately by another 300 ms On, and so
on.
In the case of CT=10.0s, on the other hand, at 50.0% we
will have a period of 500ms On and another 500ms Off.
With power at 75.0% it will be 7500ms On and 2500ms Off,
followed by another 7500ms On, and so on.
Power displays the percent power currently in use or if
used for heating or cooling.
The value indicated therefore represents the amount of
power truly delivered on the physical outputs of the
instrument, considering the evental contributions of the
parameters GRAD OUT and the SOFT START.
The pure Power % calculated by the PID algorithm is avail-
able on the page BASE2 and in the PID_nn_MAN variables.
The
A / M
icon indicates whether the operating mode is
automatic (A) or manual (M).
The
ST icon light turns on during self tuning.
4.15.4.3. PID advanced configuration
The Base 2 section lets you set PID advanced parameters.
The number of the PID to be set is displayed at the top of
the screen and can be changed using the
- and + keys.
Turn the PID on and off with the EN button. The key turns
green when the PID is enabled.
The value can be entered with the virtual keyboard by
touching some parameters.
The available parameters and functions are:
• RATIO : indicates the value of the ratio and is only
displayed if Ratio operations were set in the Synoptic
menu.
• SP : setpoint, value to be reached and maintained.
• PV : process value, current value (read only).
• Group : group of PID parameters used for regulation
chosen from the 10 available. The groups are used to