Kenco Engineering Thermal Differential Switch User Manual
Page 6
Page 6
J2 – This sets the Failsafe condition of the switch. The jumper should cover the (2) left-most pins for High Level
Failsafe (HLFS) condition, or the (2) right-most pins for Low Level Failsafe (LLFS) condition. See the table
below for the comparison of the two conditions, as well as the condition of the Red and Green LED’s.
CALIBRATION (Level Switch)
(Refer to Page #5 for location of controls)
NOTE: For optimum performance, the calibration must be done at actual process temperature.
1. Remove the Instrument Enclosure Cover
2. Ensure that the level is below the
sensor tips, and that the tips are
dry.
3. Apply power. Allow the sensor
to warm-up for five minutes.
4. Set the “Trip Point Adjust” pot to
“0” (fully counterclockwise).
5. Set the “Zero Adjust” pot so that
the Red LED just does
illuminate. This is a 25-turn pot.
If the Green LED is on, turn the
pot counterclockwise. If the Red
LED is on, turn the pot
clockwise.
6. Toggle the “Zero Adjust” pot
back and forth until the trip point
is well defined. Leave the Red
LED Illuminated.
7. Raise the level of the liquid in the
vessel until the sensor tips are
covered.
8. Set the “Trip Adjust” pot to 100
(fully clockwise).
9. Set the “Span Adjust” pot so that the Green LED just does illuminate. This is a 25-turn pot. If the Green LED is on,
turn the pot clockwise. If the Red Led is on, turn the pot counter clockwise.
10. Toggle the “Span Adjust” pot back and forth until the switching point is well defined. Leave the Green Led illuminated.
11. Set the “Trip Point Adjust” pot to 80 and the calibration is complete. Setting this pot to 80 gives an approximate equal
trip time from wet-to-dry and dry-to-wet. Setting this pot closer to “0” will speed up the dry-to-wet time, and slow down
the wet-to-dry time. Setting this pot closer to “100” will slow down the dry-to-wet time, and speed up the wet-to dry
time.
Relay Terminals
Sensor
Status
Red
LED
Green
LED
Fail Safe
Setting
Relay
Condition
NC to C
NO to C
HLFS
De-Energized
Closed
Open
Wet (Level)
or High Flow
Off
On
LLFS
Energized
Open
Closed
HLFS
Energized
Open
Closed
Dry (Level)
or Low/No Flow
On
Off
LLFS
De-Energized
Closed
Open
J2
J2
HLFS
LLFS