FACTS F4 Series Modules: F4-16AD-2 Analog Input,

Technical Dossier

Product Details And Specifications

FACTS Engineering F4 Series: Comprehensive Module Range and Technical Overview

The FACTS Engineering F4 Series is a modular programmable controller platform deployed across continuous-process industries including petrochemical refineries, water treatment facilities, pulp and paper plants, and discrete manufacturing lines. Built on a fixed-rack backplane architecture, the F4 system integrates CPU, analog I/O, discrete I/O, and communications modules into a unified control node. Its 16-slot and 8-slot rack configurations have made it a standard control platform in North American industrial installations from the late 1980s through the 2000s. The F4 Series is now in the mature-to-end-of-life phase of its product lifecycle; however, installed base density remains high, making spare parts availability a critical operational concern for maintenance engineers and reliability teams.

The Evolution of F4 Series Architecture

The FACTS Engineering F4 platform was introduced as a mid-range PLC targeting applications that required higher analog channel density than entry-level controllers but did not justify the cost of large DCS installations. The original F4 architecture used a parallel backplane bus with a proprietary rack interconnect, supporting up to 16 I/O modules per rack and multiple rack expansion via remote I/O adapters.

Early F4 deployments used 12-bit analog resolution across input and output modules. Subsequent hardware revisions introduced 16-bit resolution variants and expanded the supported signal ranges to include 4–20 mA, 0–10 VDC, ±10 VDC, and thermocouple/RTD inputs on dedicated modules. The CPU module line evolved from the F4-CPU to enhanced variants with expanded memory and faster scan times.

Compatibility across F4 hardware generations is generally maintained at the rack and backplane level; however, firmware dependencies between CPU versions and specific I/O modules must be verified before substitution. As FACTS Engineering was acquired and its product lines transitioned, direct manufacturer support for F4 hardware has been discontinued. Third-party maintenance suppliers and independent parts distributors now represent the primary sourcing channel for F4 spare modules.

F4 Series Full Catalog & Functionalities (SKU List)

Analog Input Modules

• F4-16AD-2: 16-channel analog input module, 12-bit resolution, 4–20 mA / 0–10 VDC selectable per channel
• F4-16AD-1: 16-channel analog input, voltage-only configuration, ±10 VDC range
• F4-08AD-1: 8-channel analog input module, 12-bit, 4–20 mA current input
• F4-08AD-2: 8-channel analog input, dual-range voltage/current, field-selectable
• F4-08THM: 8-channel thermocouple input module, supports J, K, T, E, R, S, B types
• F4-08RTD: 8-channel RTD input module, supports PT100, PT1000, Ni120

Analog Output Modules

• F4-08DA-1: 8-channel analog output, 4–20 mA current output, 12-bit resolution
• F4-08DA-2: 8-channel analog output, 0–10 VDC voltage output, 12-bit resolution
• F4-04DA-2: 4-channel analog output, ±10 VDC, high-drive current capability

Discrete Input Modules

• F4-16ND3: 16-channel discrete input, 24 VDC sinking/sourcing, IEC Type 3
• F4-32ND3: 32-channel discrete input, 24 VDC, high-density rack format
• F4-16NA-1: 16-channel discrete input, 120 VAC, isolated commons

Discrete Output Modules

• F4-16TD1: 16-channel transistor output, 24 VDC sourcing, 0.5 A per point
• F4-16TD2: 16-channel transistor output, 24 VDC sinking configuration
• F4-16TA-1: 16-channel triac output, 120/240 VAC, 0.5 A per point
• F4-16TR: 16-channel relay output, Form A contacts, 2 A per point at 240 VAC

CPU & Controller Modules

• F4-CPU: Base CPU module, ladder logic execution, 16K word program memory
• F4-CPU-1: Enhanced CPU, expanded 32K word memory, faster scan cycle

Communications & Networking Modules

• F4-DEVMR: DeviceNet master module, supports up to 64 nodes
• F4-PBMR: PROFIBUS-DP master module, 12 Mbps maximum baud rate

Power Supply Modules

• F4-PS: Base rack power supply, 24 VDC input, 5 VDC / 1.5 A backplane output
• F4-PS-1: High-capacity power supply, 120/240 VAC input, dual-voltage backplane output

Sourcing Hard-to-Find & Obsolete F4 Series Parts

The FACTS Engineering F4 Series has been out of active production for over a decade. OEM replacement channels are no longer available, and the installed base is supported exclusively through the secondary market. DriveKNMS maintains a dedicated inventory of F4 Series modules sourced from decommissioned plant equipment, controlled-environment warehouses, and verified industrial surplus channels.

For end-users operating F4-based control systems in long-lifecycle applications — including water infrastructure, chemical batch processing, and legacy discrete manufacturing — DriveKNMS provides lifecycle extension support including: verified used modules with functional test documentation, cross-reference assistance for identifying compatible substitute modules where direct replacements are unavailable, and bulk lot procurement for facilities maintaining multi-year spare parts buffers.

Quality Control for the F4 Series Range

F4 Series modules present specific test challenges due to their backplane-dependent initialization sequence and proprietary bus protocol. DriveKNMS applies a structured verification process to all F4 inventory prior to shipment.

Each analog module — including the F4-16AD-2 and related AD/DA variants — is bench-tested using a dedicated F4 rack with a known-good CPU module. Analog input channels are verified across the full signal range (0–20 mA and 0–10 VDC) using calibrated signal sources, and output linearity is confirmed against reference measurements. Channel-to-channel isolation is checked for leakage. Discrete I/O modules are cycled through all points under load. CPU modules are powered and subjected to a full memory read/write cycle and communication port verification. Modules that fail any test point are quarantined and not offered for sale. All passing units are labeled with a test date and technician ID before packaging.