Hoffman Controls 890-DSQ Series Complete Installation & Operating Instructions page 7

Operating Modes Con't
b. High Span Value
Temp/PSI/Volts: 80.0
Use the UP and DOWN buttons to change the high span's
value (number) to match the highest input value at which the
unit has all the fixed relay stages on, plus the VS (variable stage)
at 100% (if the VS is being used).
Press the ENTER button to store the high span's value and
continue to submenu c. below.
c. On to On=2.0 Deg/PSI/Volts
Hyster= 1.0 Deg/PSI/Volts
This submenu displays the stage spacing between successive
relay turn on values. This submenu also shows the current hys-
teresis value used for each of the activated relay stages.
The first line on the LCD's screen shows the evenly spaced
temperature, pressure or voltage differences between successive
fixed stage turn on values, calculated by the microcontroller,
using the high and low span values entered above.
The second line on the LCD's screen shows the current hys-
teresis value (in °F, PSI or volts DC) used for all the selected
relay stages. The operator may change this hysteresis value by
pressing the UP or DOWN buttons until the desired hysteresis
value, used by all the selected (fixed) relay stages, is displayed on
the LCD screen's second line. However, the selectable hysteresis
values are limited due to the span size chosen in MODES 4.1a
and 4.1b above.
NOTE:
Hysteresis is used to prevent short cycling. It is the
difference between each stage's turn on and turn off values. Press
the ENTER button to save the hysteresis value and continue to
menu 2 below.
2) Set Stage On/Off
Values Manual 1
To set any or all of the primary set points (stage turn on
and turn off) values manually, press the ENTER button.
a. Var Stage TurnOn
Temp/PSI/Volts: 50.0
If VS (variable stage) operation is selected, this screen will
appear. Use the UP and DOWN buttons to set the value at
which the continuously variable EC motors, or SCRs, first
begin to turn on. Press the ENTER button to save the value
and continue to submenu b below.
b. Stage 1 On Temp/PSI/Volts
61.5?
Use the UP and DOWN buttons to set the value at which
relay stage 1 turns on as the input rises. If the variable stage is
being used, this value must be above the value at which the
variable stage turns on. Otherwise the stage's turn on value
will default to 0.2 (°F, PSI or VDC) above the variable stage
turn on value. Press the ENTER button to continue.
c. Stage 1 Off Temp/PSI/Volts
56.0?
Use the UP and DOWN buttons to set the value at which
Stage 1 turns off as the input drops. This value must be below
the value at which Stage 1 turns on. Otherwise, the stage 1
turn off value will default to 0.1 (°F, PSI or VDC) below the
Stage 1 turn on value. Press the ENTER button to continue.
d. Stage 2 On Temp/PSI/Volts
67.0?
Use the UP and DOWN buttons to set the value at which
Stage 2 turns on as the input rises. This must be above the
value at which Stage 1 turns on. Otherwise the Stage 2 turn on
value will default to 0.2 (°F, PSI or VDC) above the Stage 1
turn on value. Press the ENTER button to continue.
IMPORTANT:
After updating any information displayed on the
LCD's screen, the installer MUST review ALL of
the 890-DSQ Sequencer's mode, menu, submenu
and numerical value options to 1) ensure that all
of the operating parameters, needed for the appli-
cation, have been correctly selected and 2) also
ensure that any unneeded or undesired options or
numerical values have not inadvertently been left
e. Stage 2 Off Temp/PSI/Volts
61.5`?
Use the UP and DOWN buttons to set the value at which
Stage 2 turns off as the input falls. This must be below the
value at which Stage 2 turns on. Otherwise the Stage 2 turn off
value will default to 0.1 (°F, PSI or VDC) below the Stage 2
turn on value. Press the ENTER button to continue.
Continue to manually set the individual relay stage's on and off
values, as described above, until the number of used output stages'
primary set points have been set.
MODE 5: Change Secondary Set Points
The 890-DSQ Series sequencers include a second set of set
points that can be stored and used when an application determined
condition occurs. The sequencer will operate using the secondary
set points when an external contact is closed, connecting the input
terminal labeled "2ND" to the adjacent "GND" terminal. Press
the ENTER button to begin setting the secondary set points.
The LCD screen will show "Set Stage On/Off Values Auto? 2".
The "2" indicates the 2 nd (secondary) set of set point values can
be changed when this menu is selected. The options available to
select these secondary set point values are identical to the options
used to set the primary set point values in MODE 4 above.
Therefore, follow the MODE 4 instructions, when the number
"2" is present on the LCD screen's menu or submenu text, to
update the secondary set points using either Auto or Manual
methods.
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selected.