WATLOW DAC / SDAC,Digital-to-Analog / Serial-to-Analog Modules

Watlow Anafaze DAC and SDAC are specialized conversion modules designed to extend the capabilities of the legacy CLS200 and MLS300 controller series.

They bridge the gap between digital pulse-width control and true analog output signals.

1. Introduction

The DAC (Digital-to-Analog Converter) and SDAC (Serial Digital-to-Analog Converter) are optional modules used to translate a controller’s logic-level signals into precision analog voltages or currents.

DAC: Typically converts “Distributed Zero Crossing” (DZC) pulse signals into 4-20mA or 0-10VDC.

SDAC: An advanced serial-driven module that converts digital data streams from the controller into a precise analog signal, used primarily for retransmitting process variables or controlling phase-angle fired SCRs.

2. Technical Parameter Table

3. Product Advantages and Features

High Precision: The SDAC offers laboratory-grade resolution (0.003%), critical for fine motor speed control or chemical dosing.

Flexible Scaling: Users can field-calibrate the “zero” and “span” values to match the specific requirements of their end-device (e.g., setting a 4.2mA floor for an aging valve).

Space Efficient: Compact, panel-mountable housing allows multiple DAC units to be “daisy-chained” or grouped near the load.

Noise Immunity: Optical isolation in the SDAC prevents high-voltage spikes from the heater power lines from feeding back into the sensitive CPU.

4. Application Cases

Motor/Belt Speed Control: Converting a temperature setpoint into an analog signal for a Variable Frequency Drive (VFD) to adjust cooling fan speeds.

Phase-Angle Fired SCRs: Providing the required 4-20mA signal to control SCR power controllers for high-wattage nichrome heaters.

PV Retransmit: Sending a “mirror” of the process temperature to a remote circular chart recorder for regulatory compliance.

Valve Actuation: Driving proportional pneumatic valves in steam-heated industrial processes.

5. Other Models in the Same Series

Dual DAC: A version that houses two independent DAC channels in a single housing.

SDAC-E: The “Enhanced” version with additional firmware support for CLS200 systems.

10045-Series: The standard part number prefix for individual DAC modules.

TB50 / TB18,High-Density Terminal Boards,Legacy / Available

AIM-TB,Analog Input Terminal Board,Legacy / Available

DAC SDAC

6. Installation and Maintenance

Installation

Mounting: Install on a flat surface or panel near the controller. The SDAC requires four mounting screws for fixed positioning.

Wiring: Use copper conductors only. Ensure the +5V supply from the controller is properly connected; the SDAC will not function without this logic-level power.

Daisy Chaining: Up to four SDAC modules can often be daisy-chained on a single clock/data line from the processor.

Maintenance

Recalibration: If the analog signal drifts, the SDAC features onboard “Zero” and “Span” potentiometers. Recalibrate annually using a calibrated multimeter.

Contact Integrity: Check screw terminal torque (recommended 0.5 to 0.6 Nm) to prevent signal flickering due to vibration.

Environmental Check: As these units are legacy devices, ensure the vents are clear of dust to prevent heat-induced accuracy drift.

7. Unique Product Description

“The Watlow DAC/SDAC modules serve as the ‘voice’ of your digital controller.

They translate the silent logic of the microprocessor into the physical language of voltage and current,

enabling the CLS and MLS series to command massive motor drives and high-power SCRs with surgical accuracy.

It is the essential hardware bridge for any process where simple On/Off control isn’t enough.”