Imod Systems LLC v. Tga Industries Ltd

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: iMod Systems LLC (New Mexico)
  • Defendant: TGA Industries Limited (United Kingdom)
  • Plaintiff’s Counsel: Rabicoff Law LLC
• Case Identification: 2:25-cv-00847, E.D. Tex., 08/22/2025
• Venue Allegations: Plaintiff alleges venue is proper because the defendant is a foreign corporation.
• Core Dispute: Plaintiff alleges that Defendant infringes a patent related to a method for determining an initial value for an industrial temperature controller to improve performance.
• Technical Context: The technology relates to Proportional-Integral-Derivative (PID) controllers, which are widely used in industrial processes to maintain stable conditions, such as temperature, by minimizing error between a desired setpoint and a measured value.
• Key Procedural History: The complaint does not mention any prior litigation, licensing history, or administrative proceedings related to the patent-in-suit.

Case Timeline

Date	Event
2005-10-14	U.S. Patent No. 7,249,882 Priority/Filing Date
2007-07-31	U.S. Patent No. 7,249,882 Issues
2025-08-22	Complaint Filed

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 7,249,882 - Method for determining integration initial value of PID controller

• Patent Identification: U.S. Patent No. 7,249,882, “Method for determining integration initial value of PID controller,” issued July 31, 2007 (the “’882 Patent”).

The Invention Explained

• Problem Addressed: The patent’s background section describes a common dilemma in industrial temperature control systems using PID controllers: achieving a target temperature quickly often causes the system to "overshoot" the target, while methods to prevent overshoot are often slow to reach the target temperature (’882 Patent, col. 1:24-29). Prior art integration control, used to eliminate steady-state error, was a "lengthy processing for obtaining stable temperature" (’882 Patent, col. 2:22-24).
• The Patented Solution: The invention proposes a method to calculate an "estimated integration initial value" before the main control process begins (’882 Patent, col. 2:54-56). This is accomplished through an "automatic tuning" phase where the system performs on-off switching to generate a temperature oscillation curve (as depicted in Figure 6). By analyzing the characteristics of this curve (e.g., its highest and lowest points), the system calculates an initial value that is then fed into the PID controller's integrator. This allows the controller to begin its operation from a more advantageous starting point, reducing the time needed to reach the set temperature and preventing overshoot (’882 Patent, col. 2:30-45).
• Technical Importance: The described method aims to resolve a fundamental trade-off between speed and stability in a widely used class of industrial control systems (’882 Patent, Abstract).

Key Claims at a Glance

• The complaint asserts infringement of at least Claim 1 of the ’882 Patent (Compl. ¶11, 16).
• Independent Claim 1 requires a method comprising the steps of:
  • performing a setting step to set a temperature setting value and a temperature error setting value;
  • performing a parameter generation step to activate an automatic tuning, wherein an on-off switching for output control is performed to obtain an amplitude curve with highest temperature and lowest temperature;
  • performing a calculation step to calculate an estimated initial value based on the integration of the amplitude and the temperature difference; and
  • using the estimated initial value for integration control of the PID controller to reduce the reaction time for achieve the set temperature.
• The complaint does not explicitly reserve the right to assert dependent claims, but generally refers to "one or more claims" (Compl. ¶11).

III. The Accused Instrumentality

Product Identification

• The complaint does not name specific accused products in its main body, referring to them generally as “Exemplary Defendant Products” that are identified in charts attached as Exhibit 2 (Compl. ¶11, 16). Exhibit 2 was not filed with the complaint.

Functionality and Market Context

• The complaint alleges that the accused products "practice the technology claimed by the '882 Patent" (Compl. ¶16). However, it does not provide any specific description of the accused products' functionality, instead incorporating by reference the allegations contained within the unattached Exhibit 2 (Compl. ¶17). The complaint does not provide sufficient detail for analysis of the accused instrumentality's functionality or market context.

IV. Analysis of Infringement Allegations

The complaint alleges that Defendant’s products infringe the ’882 patent by practicing the claimed method (Compl. ¶11, 16). It states that claim charts comparing the asserted claims to the accused products are provided in an Exhibit 2 and incorporates those charts by reference (Compl. ¶16-17). As Exhibit 2 was not provided, a claim chart summary cannot be constructed. The complaint’s narrative theory is that the "Exemplary Defendant Products incorporated in these charts satisfy all elements of the Exemplary '882 Patent Claims" (Compl. ¶16).

No probative visual evidence provided in complaint.

• Identified Points of Contention: Based on the patent and the general nature of the allegations, the infringement analysis may raise several questions:
  • Technical Questions: Does the accused product software or firmware perform a distinct "automatic tuning" phase involving "on-off switching" to generate an "amplitude curve" as required by Claim 1? What evidence does the complaint provide that the accused products "calculate an estimated initial value" using the specific inputs recited in the patent (i.e., "the integration of the amplitude and the temperature difference")?
  • Scope Questions: How will the term "automatic tuning" be construed, and does the functionality of the accused products fall within that construction? Does the method by which the accused products initialize their control parameters meet the specific "calculation" and "using" steps of Claim 1, or does it operate on a different technical principle?

V. Key Claim Terms for Construction

• The Term: "automatic tuning"

• Context and Importance: This term appears in step (b) of Claim 1 and describes the core process for generating the data needed to calculate the initial value. The patent specification links this term to a specific process of "on-off switching... between the positive and negative error setting value... to control output, thus obtaining an amplitude curve" (’882 Patent, col. 3:23-30). Practitioners may focus on this term because the defendant will likely argue that its products either do not perform "automatic tuning" at all or that their tuning method is technically distinct from the specific on-off switching process described in the patent.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The claim language itself does not detail the mechanics of the on-off switching, which could support an argument that it covers any automatic tuning process that involves generating an amplitude curve through on-off control.
  • Evidence for a Narrower Interpretation: The detailed description and Figure 6 provide a specific embodiment where the control output is switched ON until the temperature exceeds a positive error value and then switched OFF until it falls below a negative error value (’882 Patent, col. 3:50-60). This could support a narrower construction limited to this specific type of oscillatory tuning method.

• The Term: "calculate an estimated initial value based on the integration of the amplitude and the temperature difference"

• Context and Importance: This term from step (c) of Claim 1 defines how the initial value is derived. The patent’s validity and infringement positions may depend on whether this calculation is novel and whether the accused products perform it. The dispute will center on what it means to calculate a value "based on the integration" of these two parameters.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The term "based on" could be interpreted broadly to cover any calculation that uses the amplitude and temperature difference as inputs, even if the formula is not identical to the one disclosed.
  • Evidence for a Narrower Interpretation: The specification discloses a specific mathematical formula (Formula 4) for this calculation: "I=(B-G)/(A-G)(%)", where A is the amplitude, B is the temperature difference, and G is the negative error setting (’882 Patent, col. 3:36-39). A defendant could argue this specific formula defines the scope of the claim.

VI. Other Allegations

• Indirect Infringement: The complaint alleges induced infringement, stating that Defendant distributes "product literature and website materials inducing end users and others to use its products in the customary and intended manner that infringes the '882 Patent" (Compl. ¶14). The complaint notes that Exhibit 2 contains extensive references to these materials, but provides no specific examples in the body of the pleading (Compl. ¶14).
• Willful Infringement: The complaint alleges that Defendant has actual knowledge of infringement at least from the service of the complaint and its attached claim charts (Compl. ¶13). The allegations appear to be directed at establishing post-suit willful infringement (Compl. ¶14).

VII. Analyst’s Conclusion: Key Questions for the Case

• A central issue will be one of evidentiary proof: Given that the complaint lacks specific factual allegations detailing how the accused products operate, a key question will be whether Plaintiff can produce evidence demonstrating that the unnamed "Exemplary Defendant Products" actually perform each step of the claimed method, particularly the "automatic tuning" and "calculation" steps.
• The case will also turn on a question of definitional scope: The dispute will likely focus on the proper construction of the term "automatic tuning." A core issue for the court will be whether this term is limited to the specific oscillatory on-off switching method described in the patent's preferred embodiment or if it can be construed more broadly to cover other auto-tuning functionalities that may be present in the accused products.
• A final question will be one of technical implementation: Does the accused system "calculate an estimated initial value" in a manner consistent with the claims? The analysis will likely require a detailed examination of whether the accused products use a value "based on the integration of the amplitude and the temperature difference," or if they rely on a fundamentally different algorithm for parameter initialization.