Note: The value ranges and minimum control
band are determined by the Sensor Type
selected for the sensor that the output
references and are enforced in the Relay ON
and Relay OFF Selection screens.
The following figure shows an OFF value of 75
(°F) selected for Relay Output 1.
Figure 20: Standard Relay OFF Selection screen
When a relay output references Sn-d, press
Up or Down in the Differential Relay dOFF
Selection screen to select the differential
value at which output relay turns off. The dOFF
value is a differential value that represents
the intended difference in the condition
(temperature, pressure, or humidity) between
Sn-1 and Sn-2 (Sn-1 minus Sn-2) at which the
relay is turned off. Depending on the intended
control action and the physical location of Sn-1
and Sn-2 sensors in the condition process, dOFF
may be a positive or negative value. dOFF is
defined as relay LED Off, relay contacts N.C. to
C are closed, and N.O. to C contacts are open.
Press Next to save your selection and go to the
Relay-ON Delay Time Selection Screen.
Note: The unit of measurement, resolution
increment, minimum control band, and
range of usable values for dON and dOFF are
determined by the Sensor Type selected for
Sn-1 and Sn-2. (See Table 3 and Table 5 for
more information.)
The following figure shows a dOFF value of 32
(psi) selected for Relay Output 1.
Figure 21: Differential Relay dOFF Selection screen
When a Relay Output references a hard-wire
sensor (Sn-1, Sn-2, or Sn-3) that is set up with
the bin (binary input) Sensor Type, the ON and
OFF screens are not available. Relay outputs
that reference a sensor set up with the bin
Sensor Type are controlled by the binary input
contacts state (open or closed). The ON and
OFF values are not used to control relay outputs
that reference a binary input sensor. If you
select and save a sensor set up as a binary
input in Step 2, the ON Delay (ONd) screen
appears. Go to Step 5.
5. In the Relay-On Delay Time Selection screen, press
Up or Down to select the time value (in seconds) that
the output relay delays turning on after the process
condition reaches the Relay-On value. The Relay-On
Delay time range is 0 to 300 seconds. Press Next to
save your selection and go to the Relay-On Delay
Time Selection Screen.
Note: The Relay-On Delay feature can be used
to delay the output relay from going to the
On state after the On value is reached at the
referenced input sensor. The condition change
must reach or exceed the output's Relay On
value for the entire duration of the Relay-On
Delay, before the output relay goes On. This
feature can be used to prevent controlled
equipment such as actuators from being
exercised every time the condition momentarily
spikes to the Relay-On value, reducing wear on
the controlled equipment.
The following figure shows an ONd value of 30
(seconds) selected for Output 1.
Figure 22: Relay-On Delay Time Selection screen
6. In the Relay-Off Delay Time Selection screen, press
Up or Down to select the time value (in seconds) that
the output relay delays turning off after the process
condition reaches the Relay Off value. The Relay-Off
Delay time range is 0 to 300 seconds. Press Next to
save your selection and go to the Relay-Off Delay
Time Selection screen.
Note: The Relay-Off Delay feature can be used
to delay the output relay from going to the
Off state after the Off value is reached at the
referenced input sensor. The condition change
must reach or exceed the output's Relay Off
value for the entire duration of the Relay-Off
Delay, before the output relay goes Off. This
feature is used to prevent controlled equipment
such as actuators from being exercised every
time the condition momentarily spikes to
the Relay Off value, reducing wear on the
controlled equipment.
The following figure shows an OFFd value of 0
(seconds) selected for Output 1.
Figure 23: Relay-Off Delay Time Selection screen
7. In the Minimum Relay ON Time Selection screen,
press Up or Down to select the minimum time that
the output relay remains on after reaching the Relay
ON value. The minimum ON Time range is 0 to 300
seconds. Press Next to save your selection and go to
the Minimum Relay OFF Time Selection screen.
The following figure shows an ONT value of 0
(seconds) selected for Output 1.
Figure 24: Minimum Relay ON Time Selection screen
System 450 Series Control Module with Ethernet Communications Installation Guide 13
To Next Page
Loading...
Need help?
General
