3
Setting the Operating Modes
Whenever the Digi-Span is powered up, it will display the software version number and then the current operating modes.
Each display will remain on the screen approximately 5 seconds. If the modes are correct, there is no need to make any
adjustments.
Once the modes have been set for a particular application, they will be retained in memory and will not need to be reset.
Note that if you do change an operating mode, you will need to reset the set points, differential and offset.
An operating mode can only be changed when it is being displayed in the start-up sequence. To restart the sequence it is
necessary to remove power to the Digi-Span and then power it again.
Set the operating modes as described in sequence below:
30
,
100
, or
200
- Pressure Range
If the display shows
30
then the range will be from 0 to 30 psi and the display will be in 0.5psi increments. If the display
shows
100
or
200
, the range will be 0 to 100psi or 0 to 200psi and will display in one pound increments.
To change the range, hold down the center button while pushing either the
UP
or
DOWN
button to toggle between ranges
.
When the range is selected, release the buttons and wait approximately 5 seconds.
H
or
C
- Heating or Cooling (TSC/TSR only)
If the display shows
H
then the Digi-Span will be in a heating mode. The relays will close when the pressure is below the set
point (see Example on pg.6)
If the display shows
C
then the Digi-Span will be in a cooling mode. The relays will close when the pressure is above the set
point.
To change the mode, hold down the center button while pushing either the
UP
or
DOWN
button to toggle between the
displays of
H
and
C.
When the correct heating or cooling mode is selected, release the buttons and wait approximately 5 seconds.
TSC
or
TSR
- Fixed or Rotating Lead Stage (TSC/TSR only)
If the display shows
TSC
the lead stage will not rotate. Set Point 1 will always control the Black output wires, and Set Point
2 will always control the Red output wires.
If the display shows
TSR
, the lead stage will rotate every day to provide more even wear on the units being controlled; that
is, Set Point 1 will control the Black output wires one day, and the Red output wires the next day.
If any changes were made to the operating modes, the display will flash. Then the Digi-Span will display the sensor pres-
sure.
BLACK
BLACK
24 VAC
or wire 120VAC to rear
transformer (blue wires)
SENSOR
TYPICAL WIRING DIAGRAM
HEATER
or CHILLER
OUTPUT 1
OUTPUT 1
POWER
RED
RED
HEATER
or CHILLER
OUTPUT 2
OUTPUT 2
POWER
WARNING
The Digi-Span can accept only
one source of power: 120VAC
or 24VAC. If more than one
power source is applied, the
unit may be damaged.
