Control Block Operation - Pentair POINT FOUR RIU3 Guía De Instalación Y Del Usuario

The RIU3 control blocks take inputs from the probe parameters and control the state of the relays according to
some user-selected set points. The user can configure the input parameters, control type, set points, delays and
output relays for each control block. The user-selectable parameters are described in more detail below.
User-Selectable Control Block Parameters
1) Type: The Type can be set either to Control or Alarm. In alarm mode, the relay output behaves as described in
Figure 1.
In control mode, the relay output behaves as described in Figure 2
If the process value (PV) is within the user defined high and
low set points the system condition is normal. If the process
value (PV) fluctuates out of the alarm bandwidth (above the
high set point or below the low set point) the system will go
into alarm.
This is indicated on the bottom left corner of the home
screen by flashing the word "ALARM". This is also indicated
on each individual channel by the alarm symbol.
A delay time can be added to the setpoint. (E.G. A fish/plant
touches the probe, sending the conditions out of the normal
bandwidth, resulting in false alarm conditions. The delay time
allows the conditions to return to within the normal band-
width.
If the process value (PV) is within the user defined high and
low set points the system condition is normal. If the process HI SETPOINT
value (PV) fluctuates below the low set point the system will
go into a control situation. This turns on (or off depending on
normal conditions) a relay. The relay will remain on until the
process value (PV) reaches the high set point at which point
it will switch off.
LOW SETPOINT
The process can be reversed so that a relay turns on when
the process value (PV) fluctuates above the high setpoint,
depending on the customers needs.
This is indicated on each individual channel by the orange
RLY ON indicator.
A delay time can be added to the setpoint. (E.G. A fish/plant
touches the probe, sending the conditions out of the normal
bandwidth, resulting in false control conditions. The delay
time allows the conditions to return to within the normal
bandwidth. A delay can also be added to the high setpoint
which allows the system overdose, which may be applicable
in some cases.
x
PV
x x
Alarm Control Output
Alarm/Relay Active [ON]
Alarm/Relay Inactive [OFF]
POINT FOUR™ RIU3™ Remote Monitor/Controller Installation and User's

CONTROL BLOCK OPERATION

HI SETPOINT
PV
LOW SETPOINT
Alarm Control Output
Alarm/Relay Active [ON]
Alarm/Relay Inactive [OFF]
Figure 1: Alarm Mode operation
x
HI SETPOINT
PV
LOW SETPOINT
Control Band Output
Control/Relay Active [ON]
Control/Relay Inactive [OFF]
Figure 2: Control Mode operation
17
x
x x
x
x
Guide
HI
LOW