Wavelength Electronics WHY56ND, Datasheet And Operating Manual

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WHY56ND TEMPERATURE CONTROLLER
STEP 2 CONFIGURE THE HEAT AND COOL
CURRENT LIMITS
Adjust the current limits using the LIMA and LIMB trimpots
on the WHY56ND‑EV. 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 current limit value. Use Table 7 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 WHY56ND‑EV outputs (OUTPUT A or
OUTPUT B) to your thermoelectric or resistive heater using
Table 8 as 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 WHY56ND‑EV allows for operation of the board with
NTC thermistors in the range of 0 ‑ 20 kΩ.
NOTE: Contact Wavelength Electronics to use the
WHY56ND‑EV 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 website . The V
DD
power
supply is used to power the WHY56ND internal control
electronics and must be capable of supplying 100 mA of
current. The V
S
power supply is used to power the WHY56ND
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 WHY56ND
component and minimize your heatsinking requirements.
Set the ENABLE Switch to OFF before powering the
WHY56ND. 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
WHY56ND‑EV 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
WHY56ND 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 page 10 . The I term adjusts R
G
in the equations on
page 10 , while the P term adjusts R
L
. C
L
and R
L
are both
related to R
G
in Equation 5 and Equation 6 .