DESCRIPTION

This board is a shell version of the PWM3TP with the same functionality but only 2 instead of 3 channels for an easy integration with Arduino projects.

It provides galvanic separation between your project and power devices such as variable frequency drives, servo motors and any other actuator with a control analog input. Each channel provides a trim-pot to adjust the output level in the range 5 to 15 V.

Two jumper selectors with three position each allow the use of any of the 6 PWM pins of the Arduino UNO. The Arduino MEGA2560 has 15 PWM pins but only 6 of them can be used in this board.

• Channel 1: Pins 6, 9 or 11
• Channel 2: Pins 3, 5, or 10

The board is fitted with standard 0.2″ screw terminals for easy wiring to external devices.

OPTIONS

There are three versions of the board that differ only in the type of components used (see pictures):

• PWM2AT - Standard version with through hole components.
• PWM2AS - Surface mounted components with the exception of the optocouplers that are conventional through hole.
• PWM2AS1 - Surface mounted components only.

FEATURES

• Adjustable output level
• Optical isolation
• Independent channels
• Socket mounted ICs

SPECIFICATIONS

• Number of channels :2
• PWM input: TTL level. Max frequency 1KHz, 5mA @ 5V
• Output: Adjustable 0 to 5..15V
• Conversion system: MOSFET Totem-Pole
• Output filter: Low Pass 2 Pole Butterworth, 1.6Hz (-12dB/Octave)
• Output ripple: < 10mVpp at 500Hz
• Linearity: 1% FSD minimum
• Isolation: Min. 500 Vac
• Power: Nominal 24 Vdc (Acceptable range 12 to 30Vdc). At 12V the output level is limited to 10V.
• Power consumption: max. 5mA (12 to 30V) plus output current (max. 5mA)
• Dimensions: 2.700 x 2.100 in. (69 x 54 mm) 1.15 oz (0.033 Kg)

ASSEMBLY

The boards are shipped fully assembled and tested. NOTE: The headers are designed for the UNO-R3. If you want to install the shell in an older version you may need to cut short the extra pins that are not present in earlier products.

USAGE

• Install the jumpers for each channel in the position corresponding to the PWM pin to use.
• Connect the power supply to the board (12 to 30V)
• Use the instruction analogWrite(pinNumber, value), where pinNumber is the pin selected in the jumper block and value is between 0 and 255.
• The analog output will be: value * Vfsd / 255, where Vfsd is the maximum output adjusted and is set to 10V from factory.

CALIBRATION

• Set the PWM output to 0% duty cycle (analogWrite(pinNumber, 0) and verify that the analog output is 0 to 25mV.
• Set the PWM output to 100% duty cycle (analogWrite(pinNumber, 255) and adjust the level trimpot to read the required value (5 to 15V).

NOTE. You may power the board with only 10Vdc, but then the output can be adjusted only to 5-6V. This can be useful to connect commercial drives that provide only 10Vdc auxiliar power and have an input scaling parameter to use only 5Vfsd for the analog input.