© 2023
15
WHY5640 TEMPERATURE CONTROLLER
STEP 2
CONFIGURE THE HEAT AND COOL
CURRENT LIMITS
Adjust the current limits using the LIMA and LIMB trimpots
on the WHY5690. The evaluation board’s LIMA and LIMB
trimpots independently adjust the heat and cool current
limits from zero to a full 2.0 A. Clockwise turns will increase
the limit, and counter-clockwise turns will decrease the
to adjust the heat and cool
current limits.
Do not exceed SOA limits
.
Table 7.
LIMA and LIMB Current Limit Trimpot Configuration
SENSOR
TYPE
LOAD TYPE
LIMA
TRIMPOT
LIMB
TRIMPOT
Thermistor
Thermoelectric
Cool Current
Limit
Heat Current
Limit
Thermistor
Resistive
Heater
Turn Fully
CCW
Heat Current
Limit
STEP 3
CONNECT THE THERMAL LOAD
Connect the WHY5690 outputs (OUTPUT A or OUTPUT B)
to your thermoelectric or resistive heater using
a guide.
Table 8.
Output Configuration
SENSOR
TYPE
LOAD
TYPE
OUTPUT A
OUTPUT B
Thermistor
Thermo-
electric
Negative TEC
Terminal
Positive TEC
Terminal
Thermistor Resistive
Heater
Quick Connection:
Simply connect
the resistive heater to OUTA and
OUTB. Adjust the cooling current limit
to zero by turning the LIMA trimpot
fully counterclockwise.
Maximum Voltage Connection:
Connect one side of the resistive
heater to OUTB and the other side to
the voltage source V
S
.
RTD
Resistive
Heater
Maximum Voltage Connection:
Connect one side of the resistive
heater to OUTA and the other side to
the voltage source V
S
.
NOTE: Adjust the cooling current limit
to zero by turning the LIMB trimpot
fully counterclockwise.
STEP 4
CONNECT YOUR TEMPERATURE
SENSOR
Connect the temperature sensor to the and Sensor-
leads on the 4-wire output cable. The default configuration
of the WHY5690 allows for operation of the board with NTC
thermistors in the range of 0 - 20 kΩ.
NOTE:
Contact Wavelength Electronics to use the WHY5690
with other sensors or ranges.
STEP 5
ATTACHING THE V
DD
AND V
S
POWER SUPPLIES
Ensure that the controller can be safely operated by
checking the SOA Calculator
. The V
DD
power
supply is used to power the WHY5640 internal control
electronics and must be capable of supplying 100 mA of
current. The V
S
power supply is used to power the WHY5640
output H-Bridge and must be capable of supplying a current
greater than the LIMA and LIMB current limit settings. For
simple operation tie V
DD
to V
S
. A separate V
S
power supply
allows the H-Bridge to operate at a voltage different from the
4.5 V required by the V
DD
supply. Select V
S
approximately
2.5 V above the maximum voltage drop across OUTA and
OUTB to reduce the power dissipation in the WHY5640
component and minimize your heatsinking requirements. Set
the ENABLE Switch to OFF before powering the WHY5640.
Connect both power supplies via the PGND line in the input
connector. For high impedance resistance loads, a higher
voltage V
S
power supply may be required.
!
The COMMON (COM) terminal on the WHY5690
is not intended to act as a power connection,
but as a low noise ground reference for
monitor signals.
Once power is connected to the Evaluation Board, all
control electronics are powered, however there is no
drive current available to other components until the
WHY5640 Enable switch is ON.
STEP 6
ADJUST THE LOOP
COMPENSATION PROPORTIONAL GAIN AND
INTEGRATOR TIME CONSTANT
Adjust the two trimpots named “P GAIN” and “I TERM” to
change the proportional gain and integrator time constant
for the control loop to optimize the control parameters of
your system. The “I TERM” adjustment affects both the
proportional and integrator parameters while the proportional
setting affects only the proportional gain.
For a better explanation of how the I term and P term trimpots
affect the parameters of the control system, see
STEP 4
on
. The I term adjusts R
G
in the equations on
, while the P term adjusts R
L
. C
L
and R
L
are both
related to R
G
in
Equation 5
and
Equation 6
.
