© 2022
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WHY56ND TEMPERATURE CONTROLLER
PIN DESCRIPTIONS
Table 1. WHY56ND Temperature Controller Pin Descriptions
PIN
NAME
PIN DESCRIPTION
1
AGND
Analog Ground
. This is internally connected to Pins 11 and 12 (the power supply ground
connections) and eliminates grounds loops for stable operation of the sensor amplifier bridge and
limit current resistors.
2
LIMB
Limit B
. A resistor connected between Pin 2 (LIMB) and Pin 1 (AGND) sets the maximum output
current drawn from the Pin 10 (V
S
) supply input and delivered to Pin 13 (OUTB). This is cooling
current limit when used with NTC sensors.
3
LIMA
Limit A
. A resistor connected between Pin 3 (LIMA) and Pin 1 (AGND) sets the maximum output
current drawn from the Pin 10 (V
S
) supply input and delivered to Pin 9 (OUTA). This is heating current
limit when used with NTC sensors.
4
BUFA
Buffer A
. Connect Pin 4 (BUFA) to Pin 3 (LIMA) of another WHY56ND when operating the devices
in a master/booster configuration.
5
PI
Proportional Gain and Integrator Time Constant
. When using the WHY56ND as a standard PI
controller, connect one end of the proportional gain resistors R
G
and R
L
to Pin 5 (PI). R
L
will also
connect in series with C
L
to Pin 3 (LIMA). R
G
will also connect to Pin 6 (ERR).
6
ERR
Temperature Error Input
. When using the WHY56ND as a standard PI controller, connect one end
of the proportional gain resistor R
G
to Pin 6 (ERR) and the other end to Pin 5 (PI).
7
SENS
Sensor and Setpoint Input
. Pin 7 (SENS) is the common sensor bridge amplifier connection for the
sensor, R
T
, and setpoint, R
S
, resistors.
8
VDD
Control Electronics Supply Input
. Power supply input for the WHY56ND’s internal control
electronics. Supply range input for this pin is +5 to +26 VDC.
9
OUTA
Thermoelectric Output A
. Connect Pin 9 (OUTA) to the negative terminal on the thermoelectric
when controlling temperature with Negative Temperature Coefficient thermistors. OUTA provides
the heating current when using an NTC sensor. Connect Pin 9 (OUTA) to the positive thermoelectric
terminal when using Positive Temperature Coefficient RTDs.
10
VS
Power Drive Supply Input
. Provides power to the WHY56ND H‑Bridge Power Stage. Supply range
input for this pin is +4.5 to +30 VDC. The maximum current drain on this terminal should not exceed
2.5 A.
11
PGND
Power Drive Supply Ground
. Connect the V
S
power supply ground connection to Pin 11 (PGND).
Pin 11 (PGND) and Pin 12 (CGND) are internally connected.
12
CGND
Control Electronics Supply Ground
. Connect the V
DD
supply ground connection to Pin 12 (CGND).
Pin 12 (CGND) and Pin 11 (PGND) are internally connected.
13
OUTB
Thermoelectric Output B
. Connect Pin 13 (OUTB) to the positive terminal on the thermoelectric
when controlling temperature with Negative Temperature Coefficient thermistors. OUTB provides the
cooling current when using an NTC sensor. Connect Pin 13 (OUTB) to the negative thermoelectric
terminal when using Positive Temperature Coefficient RTDs.
14
BUFB
Buffer B
. Connect Pin 14 (BUFB) to Pin 2 (LIMB) of another WHY56ND when operating the devices
in a master/booster configuration.
NOTE: If you are upgrading from the WHY56ND to the WTC32ND: The position of Pin 1 on the WHY56ND is reversed
(or mirrored) relative to the position of Pin 1 on the WTC32ND.
