Power Supply Connection to FTA

Introduction

Field Terminal Assemblies (FTAs) act as the interface between your I/O modules and field devices. While Passive FTAs require no power, Active FTAs must be connected to a 24V DC supply to power their internal diagnostics and electronics. Proper installation of this power connection is crucial for safe and reliable operation.

Applicable for:

✅ Active FTAs (Analog Output, Digital Input)
❌ Not applicable for Passive FTAs

Step 1: Turn Off Power Only for the FTA You Are Installing

Do not switch off the entire Switched-Mode Power Supply (SMPS) or system power, as it may shut down the whole plant.
Find the fuse terminal block connected to the FTA module you want to install.
Open or disconnect only that fuse to cut power to just that FTA.
Once the power to that FTA is off, you can safely begin the installation.

Step 2: Locate Power Terminals on the FTA

Find the designated +24V and 0V screw terminals on your FTA.
These terminals are generally marked clearly on the FTA label or housing.
🔴 +24V Terminal – Connects to the positive lead of the power supply
⚫ 0V Terminal – Connects to the negative/ground lead

📌 Always refer to the product’s datasheet to verify terminal positions and specifications.

Step 3: Prepare the Wires

Use wire sizes between 0.2 mm² and 2.5 mm² depending on your FTA specs.
Strip approximately 7 mm of insulation from the wire ends.
Crimp ferrules (recommended) to prevent wire fraying and ensure better conductivity.

Step 4: Connect the Wires to the FTA

Insert the red wire into the +24V terminal
Insert the black or blue wire into the 0V terminal
Tighten the terminal screws to 0.5–0.6 Nm torque using a screwdriver.

⚠️ Ensure wires are securely fastened with no exposed copper strands.

Step 5: Final Verification

Recheck that all terminal screws are tight and no strands are loose.
Make sure the polarity is correct: +24V to red, 0V to black/blue.

Step 6: Power ON and Check Status

Turn ON the 24V DC power supply
Check the Power LED on the FTA — it should light up green, indicating proper operation.
If the LED does not turn on, recheck wiring and supply voltage.

Connection of Prefabricated Cables (I/O Module ➜ FTA)

Introduction

Prefabricated cables provide a quick and error-free method of connecting Saksham I/O modules to FTAs using D-Sub connectors. These cables minimize manual wiring errors and speed up installation with plug-and-play convenience.

Step 1: Ensure Power is OFF

As with all wiring procedures, turn OFF the 24V DC power supply before installation to prevent short circuits or electric shock.

Step 2: Identify the Cable Ends

Each prefabricated cable comes with 37-pin D-Sub connectors on both ends (male type).
Use the labels or markings on the cable to determine the correct end for:
The I/O Module
The FTA

Power connection

Step 3: Connect to the I/O Module

Locate the D-Sub 37-pin port on your I/O module (AI, AO, DI, or DO).
Align the connector carefully with the port.
Gently push in and fasten the connector using UNC 4-40 screws.

🔧 Avoid over-tightening the screws as this can damage the port threading.

Step 4: Connect to the FTA

Plug the other end of the cable into the FTA’s D-Sub 37-pin port.
Tighten both side screws to ensure a firm and vibration-proof connection.

Step 5: Check Cable Routing

Make sure the cable is:

Not stretched, twisted, or bent sharply
Properly routed using DIN rail cable holders or clips
Avoid routing cables near high-voltage lines or noisy electrical sources.

Step 6: Final Check

Confirm both ends are: - Fully inserted and secured - Free from tension or mechanical strain - Ensure no loose connections are present.

Step 7: Power ON and Test

Turn on the 24V DC power
Check the LED indicators on both the I/O module and the FTA
Perform a basic I/O signal test to verify proper communication between module and FTA

📌 Important Notes:

Label each cable at both ends for easy identification during maintenance.
Use dust covers on unused D-Sub ports to protect from contaminants.