Hoffman Controls 890-DSQ Series Complete Installation & Operating Instructions page 6

Operating Modes Con't
4) Stage On Delay in seconds: 2
Use the UP and DOWN buttons to change the delay after
a previous relay stage turns on, until the next relay stage can
turn on. The range is 0.0 to 10.0 seconds. (Entering 0.0 acti-
vates the relay stages as quickly as possible).
MODE 3: Change Input Settings.
In this mode, the number of input stages used, the sensor
combination rule used (see MODE 3.2, below) and the
Emergency On value can be changed/updated, from the pre-
programmed value, by pressing the ENTER button when the
above screen appears on the LCD's screens.
The LCD sequences thru the following 3 menu screens with
each press of the ENTER button:
1) Number of Inputs Used: 1
There are three types of input options available on the 890-
DSQ Sequencer; temperature sensors, pressure transducers and
the 0-10 VDC input. Use the UP and DOWN buttons to set
the number of inputs used. (The range is 0 to 6).
When the number of inputs used is set to "0", the 0-10
VDC input is used instead of the six 0-5 VDC temperature
sensors or pressure transducer inputs. NOTE: The six tem-
perature sensors and six pressure transducer inputs are ignored
when the number of inputs is set to "0".
Press the ENTER button to store the value selected, for the
number of inputs used, and proceed to the submenu below.
2) Input Combination Rule: Maximum
This screen is only displayed when more then a single
temperature sensor or pressure transducer input is used. The
installer must choose 1 of 4 possible ways to combine the
temperature sensors or pressure transducer's input values.
The four choices are; Maximum, Second Highest, Average or
Median.
Maximum
The option is chosen when only the sensor or
transducer with the highest input value will be used to control
the sequencer's operation.
Second Highest
The option is chosen when only the sec-
ond highest sensor or transducer input value will be used to
control the sequencer's operation.
Average
The option is chosen when the numerical average
of all used sensor or all used transducer input values will be
used to control the sequencer's operation.
Median
The option is chosen when the middle value of all
used sensors or all used transducer input values will be used to
control the sequencer's operation.
Use the UP and DOWN buttons to sequentially display
(cycle thru) each of the four combination rules. Then press the
ENTER button, when the desired rule is visible on the LCD
screen, to store that combination rule and continue to the next
menu.
3) Emergency On Temp/Pres: 95.0
This screen appears when temperature sensor or pressure
transducer inputs are selected. If any of the used temperature
sensor or pressure transducer input values reach or exceed the
selected Emergency On value (max 115 °F or 1000 PSI), all
of the remaining inactivated relay stages will turn on sequen-
tially. Use the UP and DOWN buttons to select the desired
Emergency On temperature, then press the ENTER button to
store the value and continue to the next mode below.
MODE 4: Change Primary Set Points
The primary set point values can be changed/updated, from the
pre-programmed set point values, by pressing the ENTER button
when the above screen appears on the LCD screen.
When the number of fixed output stages is selected, the 890-
DSQ Sequencer loads a pre-programmed set of turn-on and
turn-off set points into the microcontroller's memory. The installer
can use the pre-programmed set points or modify any or all of
these set points as required by the application.
To change all of the set point values automatically, see MODE
4.1 below. To manually update any or all of the set point values
individually, see MODE 4.2 on page 7.
The stage's turn on and turn off values are associated with one
of the 3 input types; temperature, pressure or 0-10 VDC. The
set point values are in °F when the inputs used are temperature
sensors, PSI when the inputs used are pressure transducers or volts
DC when the 0-10 VDC input is used.
The LCD sequences thru the following 3 menu screens with
each press of the ENTER button:
1) Set Stage On/Off
Values Auto? 1
This menu is used to automatically set all of the used stages'
primary on and off values by uniformly distributing the stage's
operation over a selectable span. The selectable span's low and high
values are set in the first two submenus below. The third submenu
displays the calculated stage turn on spacing and resulting stages'
hysteresis. The number "1", in this menu's LCD screen, indicates
the primary set points can be changed at this time. Press the
ENTER button to start the automatic selection process.
To independently set each stages' on and off values manually,
press the UP or DOWN button ONCE and then press the ENTER
button to advance the LCD's screen to MODE 4.2, Set Stage On/
Off Values Manual 1 (on page 7).
a. Low Span Value
Temp/PSI/Volts: 50.0
Use the UP and DOWN buttons to change the low span's value
(number) to match the lowest input value at which the unit will
come on. If the VS (variable stage) has not been selected, this is
the value at which stage 1 turns on. If the VS (variable stage) has
been selected, this is the value at which the variable speed EC
motors begin to increase speed from 0 rpm, or the SCR begins
supplying current to the heater.
Press the ENTER button to store the low span's value and
continue to submenu b (on page 7).
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