Product Overview

The ABB DSDP170 with part number 57160001-ADF is an isolated analog input module designed for ABB distributed control systems, including the Advant Master and MOD 300 series. This module provides multiple channels of 4-20 mA analog input for measuring process variables such as pressure, temperature, flow, and level from field transmitters. The DSDP170 is part of the S100 I/O system, which is a modular and flexible I/O platform for ABB DCS solutions. The module features channel-to-system isolation, which provides galvanic separation between each input channel and the control system backplane. This isolation ensures high noise rejection, prevents ground loops, and protects the control system from field wiring faults. The DSDP170 also supports HART pass-through communication, allowing the control system to exchange digital data with HART-enabled smart transmitters for configuration, diagnostics, and additional process variables.

Technical Specifications

Analog Input Measurement

The DSDP170 measures 4-20 mA current loop signals from two-wire or four-wire field transmitters. The 4-20 mA standard is widely used in process automation because it provides a live zero: 4 mA typically represents the lower range value (0 percent), 20 mA represents the upper range value (100 percent), and a reading of 0 mA indicates a loop break or power failure. The module includes a precision 250 ohm burden resistor for converting the current signal to a voltage that can be measured by the analog-to-digital converter. The 16-bit resolution provides fine granularity, allowing detection of small changes in the process variable. The module includes software configurable input filtering, which averages multiple samples to reduce the effects of electrical noise. The filter time constant can be adjusted from 0 to 1000 milliseconds, allowing the user to trade off between noise rejection and response time. The module also supports linearization of non-linear input signals, allowing the raw current reading to be converted directly to engineering units such as PSI, degrees Celsius, or gallons per minute.

Isolation Architecture

The DSDP170 provides three levels of isolation for maximum signal integrity and system protection. Channel-to-channel isolation ensures that a fault on one input channel, such as a short circuit or overvoltage, does not affect the measurement on adjacent channels. This is particularly important in applications where transmitters are powered from different power supplies or are located in different ground potential environments. Channel-to-system isolation separates the analog input circuitry from the I/O backplane and the rest of the control system, preventing ground loops and protecting the controller from field wiring faults. The isolation is rated at 500V AC for one minute, providing robust protection for typical industrial applications. The module also includes input overvoltage protection, clamping input voltages to safe levels in the event of wiring errors or transient surges.

HART Pass-Through Communication

The DSDP170 supports HART pass-through communication, allowing the control system to communicate digitally with HART-enabled smart transmitters without additional hardware. HART (Highway Addressable Remote Transducer) is a hybrid communication protocol that superimposes a digital frequency signal on top of the standard 4-20 mA analog current loop. The DSDP170 passes these HART signals through to the control system, where they can be processed by the HART communication driver. This enables the control system to perform HART commands such as reading the transmitter's primary variable, secondary variables, device status, and diagnostic information. The module also supports HART configuration commands, allowing the transmitter to be configured remotely from the control system engineering workstation. The DSDP170 is compatible with HART versions 5, 6, and 7, ensuring interoperability with a wide range of HART-enabled field devices from multiple manufacturers. The HART communication is transparent to the analog measurement, which continues to operate normally while digital communication occurs.

Key Features and Benefits

Applications

The ABB DSDP170 is used in process automation applications requiring accurate analog input measurement. Typical applications include pressure monitoring in oil and gas pipelines and refineries, temperature measurement in chemical reactors and distillation columns, flow measurement in water and wastewater treatment plants, and level measurement in storage tanks and silos.

Configuration and Diagnostics

The DSDP170 is configured using ABB engineering software such as Control Builder or Advant Master engineering tools. The configuration includes setting the input range, filter time constant, scaling to engineering units, and HART pass-through parameters. The module provides comprehensive diagnostic information, including per-channel status, open-circuit detection, and over-range detection. Diagnostic events are reported to the control system and can be displayed on operator workstations. The module includes LED indicators on the front panel for power, communication, and channel fault status.

Standards Compliance

The DSDP170 complies with relevant IEC standards for industrial measurement and control equipment, including IEC 61131-2 and IEC 61000 for EMC. The module holds CE certification and meets HART Communication Foundation specifications for HART pass-through devices.