SRD 988 Positioner: Features, Setup, and Smart Capabilities Explained

The SRD 988 Positioner is one of the most advanced smart positioners in the Schneider Electric portfolio—designed for precision control, reliability, and seamless integration into modern industrial automation systems. At KV Controls, we pride ourselves on supplying cutting-edge instrumentation and control solutions like the SRD 988 to industries across South Africa.

Below, we answer some of the most common questions about the SRD 988 to help you understand its capabilities and why it’s a top choice for intelligent valve positioning.

1. What is an SRD 988 Positioner and What Are Its Main Features?

The SRD 988 is a digital valve positioner used for controlling pneumatic actuators via a 4–20 mA signal. It ensures accurate valve positioning while providing extensive feedback and diagnostics.

Key features include:

HART 7 and Profibus PA communication compatibility
Large, multilingual graphic display for local operation
Non-contact position sensing for long-term reliability
Advanced diagnostics to monitor valve health and performance
Explosion-proof and intrinsically safe versions for hazardous areas
Auto calibration and valve signature recording
Robust design suitable for harsh industrial environments

2. How Do I Install and Start Up the SRD 988?

Installation of the SRD 988 is designed to be straightforward. The unit is typically mounted directly to a pneumatic actuator using a standard NAMUR interface or custom mounting kits.

Start-up involves:

Mechanical installation and pneumatic connection
Electrical wiring to the 4–20 mA input loop
Using the local pushbuttons and display or communication software to initiate the auto calibration sequence
Confirming actuator movement and ensuring full travel range

KV Controls offers support services and technical guidance to assist you during installation and commissioning.

3. What Kind of Communication Does the SRD 988 Support?

The SRD 988 supports multiple communication protocols, making it highly adaptable in modern industrial networks.

Supported protocols include:

HART (Highway Addressable Remote Transducer) — for two-way digital communication over analog lines
Profibus PA — for process automation networks
Optional Bluetooth or handheld communicator integration for field configuration

This flexibility allows integration with a wide range of control systems and asset management platforms.

4. How Do I Configure Settings (e.g., Stroke, Input/Output)?

Configuration can be done in three main ways:

Locally, via the onboard display and pushbuttons
Remotely, using HART or Profibus configuration tools like PACTware or FieldCare
Via auto-setup, where the SRD 988 automatically detects the valve stroke, direction, and adjusts internal parameters

Users can also manually fine-tune:

Stroke limits
Input/output characteristics
Split-range control
PID settings for precise loop tuning

5. What Diagnostics and Auto Calibration Capabilities Are Included?

The SRD 988 is equipped with advanced self-diagnostics and auto-calibration functions that make maintenance easier and reduce unexpected downtime.

Diagnostic features:

Valve travel time and friction monitoring
Air supply pressure monitoring
Signature curve comparison
Alarm logging and real-time alerts

Auto calibration ensures fast, accurate actuator setup by automatically adjusting travel and response without manual intervention. This is especially helpful in critical or hard-to-reach installations.

Why Choose KV Controls as Your Supplier?

At KV Controls, we are committed to offering our clients expert advice, technical support, and a wide selection of high-quality process control equipment—including the SRD 988 Positioner. Whether you’re upgrading your plant or troubleshooting existing systems, our team is ready to help you make the most of your investment in smart valve automation.