This board contains one PWM to analog converter that provides a linear output proportional to the duty cycle of the input signal. Its intended application is to interface micro-controllers with PWM outputs to industrial devices that require linear analog signals, such as Variable Frequency Drives (VFD), direct flame burners, and other similar devices.

The PWM input level can be 3.3, 5 or 12 V to accommodate various logic levels. The output is adjustable from 0 to 10V via a 20-turn potentiomenter (see specs below), a common standard for many industrial actuators.

The board provides two operation modes: Fixed or Adjustable. In Fixed mode, the output voltage range is 0 to Va, where Va is the power voltage. In Adjustable mode, the output voltage is adjustable from 5V to 12V.

The board allows two selectable power ranges: 10-15V or 15-24V. In addition, a built-in voltage doubler allows a 12 V output level, even when the power is as low as 10V.

Most small micro-controllers do not have proper D/A converters to produce analog outputs. Instead, they provide PWM signals that can be converted to analog values using an LP filter. This approach is good enough to generate 0-3.3V or 0-5V analog outputs (depending on the logic level of the controller) to control small powered devices. Still, it is not suitable to interface with high-power systems, such as VFDs or Servo controllers for electric motors.

When the actuator (i.e. VFD) provides its own "wetting" voltage (typically 10V), the converter can be powered directly from this supply bypassing the internal regulator. With this setting, the maximum output voltage is equal to the power supply, and no level adjustment is necessary. The board is fitted with standard 0.2" terminals and is available in two options: With or without enclosure. The optional DIN rail enclosure allows easy integration in electrical cabinets. Alternatively, you may order the enclosures directly from one of the suppliers listed below.

FEATURES

• Adjustable output level
• Optical isolation
• Surface Mounted Technology (SMT)
• Fits in standard DIN rail enclosure (see options)

SPECIFICATIONS

• Number of channels: 1
• PWM input:    Selectable 3.3, 5 or 12V, Max frequency 1 KHz (10Khz with reduced linearilty)
• Output: Adjustable 0 to 5..12V, 1KOhm impedance.
• Linearity: 2% FSD
• Isolation: Min. 500 Vac
• Power: 10-15V or 15-24V jumper selectable
• Dimensions: 3.400 x 2.700 in. (87 x 69 mm)
• Weight: 1.25 oz (0.035 Kg)

ENCLOSURES

• Bud Industries DMB4770
• Digikey DMB4770
• Mouser DMB4770
• Newark DMB-4770
• Velleman GD2MG
• CamdenBox CNMB/2/kit