Communication and parameterization module for price-based influencing of existing control systems via fieldbus or data network

Abstract

Device for influencing at least one operating parameter of an existing control and / or regulating device (11) of a technical system, in particular a refrigeration, air conditioning or HVAC system, characterized by (i) Means (2, 3) for determining an external control variable (in particular electricity price / cost time series, CO2 intensity, grid signal or flexibility signal) and for determining a price / cost index derived therefrom and / or a control variable (setpoint offset and / or demand limit); (ii) a communication interface (4) for writing at least one operating parameter, in particular a setpoint, operating mode and / or a power / demand limit, to an existing control / regulation device (11) via a fieldbus or data network-based connection, including but not limited to BACnet, Modbus, KNX, OPC UA, MQTT, HTTP / REST, WebSocket, Ethernet / IP, M-Bus or CAN; (iii) a failsafe mechanism (9) which automatically resets to a predefined safe operating state in the absence of valid control variables and / or in the event of communication / software errors, in particular by reverting set values, holding a last valid value for a maximum hold time and / or setting conservative default parameters.

Description

Technical field

[0001] The invention relates to the price- or cost-driven influencing of operational parameters in existing control systems of technical plants, in particular in the field of refrigeration / HVAC and building automation. State of the art

[0002] Flexible loads are increasingly operated using external control variables (electricity prices, CO2 intensity, grid signals). Existing buildings often have controllers and fieldbus / network interfaces; however, retrofit-compatible, reliable modules that reliably translate control variables into bus-side control variables (setpoint / mode / demand limit) and integrate parameterization, safety limits, and failsafe functionality are lacking. Task

[0003] The aim is to provide an easily retrofittable communication and parameterization module that directly intervenes in existing controllers via common fieldbus / data protocols, takes hysteresis / time-based constraints into account, handles fault cases safely and is auditable - without changing the controller. Solution

[0004] The problem is solved by the device according to claim 1 and the arrangement according to claim 13. Key elements are: (i) determination of a price / cost index or a control variable; (ii) write access to setpoints / modes / demand limits via fieldbus or data network (including BACnet / Modbus / KNX / OPC UA / MQTT / HTTP / REST / WebSocket / Ethernet / IP / M-Bus / CAN); (iii) failsafe with timeout / reset / hold; (iv) parameterization (thresholds, hysteresis, minimum times, calendar); (v) whitelist / diagnostics / logging; (vi) RTC / cache for stand-alone operation. Examples of implementation • BACnet example: The module periodically writes a cooling setpoint offset as an analog value to priority 8 and reverts it via relinkush default on timeout. In case of a communication error, it sets OUT_OF_SERVICE of a diagnostic object. • Modbus example: A demand limit register (kW) is set depending on a normalized index; each change is logged with a timestamp / CRC; if no valid data is received, the limit is reset to a conservative value. • HTTP / MQTT / OPC UA: A “ / setpoint-offset” endpoint is served via REST; a topic “site / xyz / demand-limit” via MQTT; a node “DemandLimit” including quality is set via OPC UA. Advantages • No need to change controllers, compatible with common GA / refrigeration systems. • Operational stability through hysteresis, minimum times, defined failsafe strategies. • Security / compliance via whitelist, diagnostics and audit logs. • Standalone operation without permanent cloud dependency. Reference symbol list

[0005] (1) Module; (2) Processing unit; (3) Memory / Cache; (4) Communication interface; (5) Network connection; (6) Override input; (7) Watchdog / Relay; (8) Parameterization device; (9) Failsafe; (10) Diagnostics / Status; (11) Control / Regulation device; (12) System / Actuator. Summary

[0006] A retrofit communication and parameterization module influences existing control devices via fieldbus / data protocols (including BACnet / Modbus / KNX / OPC UA / MQTT / HTTP / REST / WebSocket) based on a price / cost index or setpoint determined from external control variables. It writes setpoints / modes / demand limits, offers parameterization, failsafe (timeout / reset / hold), diagnostics and audit logs, operates autonomously thanks to RTC / cache, and is particularly suitable for refrigeration / HVAC systems.

Claims

[1] Device for influencing at least one operating parameter of an existing control and / or regulating device (11) of a technical system, in particular a refrigeration, air conditioning or HVAC system, characterized by (i) Means (2, 3) for determining an external control variable (in particular electricity price / cost time series, CO2 intensity, grid signal or flexibility signal) and for determining a price / cost index derived therefrom and / or a control variable (setpoint offset and / or demand limit); (ii) a communication interface (4) for writing at least one operating parameter, in particular a setpoint, operating mode and / or a power / demand limit, to an existing control / regulation device (11) via a fieldbus or data network-based connection, including but not limited to BACnet, Modbus, KNX, OPC UA, MQTT, HTTP / REST, WebSocket, Ethernet / IP, M-Bus or CAN; (iii) a failsafe mechanism (9) which automatically resets to a predefined safe operating state in the absence of valid control variables and / or in the event of communication / software errors, in particular by reverting set values, holding a last valid value for a maximum hold time and / or setting conservative default parameters. [2] Device according to claim 1, characterized by , that in BACnet an Analog Value (AV), Binary Value (BV) or Multistate Value (MSV) is written at a defined priority level and a retraction is performed via Relinquish Default; furthermore, an OUT_OF_SERVICE flag and / or a diagnostic object is set for error identification. [3] Device according to any one of the preceding claims, characterized by, that in Modbus a demand limit and / or setpoint offset register is written, whereby each write operation is logged with a timestamp and checksum and is reset to a safe register value in case of timeout. [4] Device according to any one of the preceding claims, characterized by , that in OPC UA a node of an address space can be writable with a quality / status flag, and / or that standardized topics / endpoints are served via MQTT / HTTP / REST / WebSocket for setpoint / mode / demand limit. [5] Device according to any one of the preceding claims, characterized by , that parameterization means (8) are provided for thresholds / hysteresis, minimum on / off times, blocking / release windows (calendar) and maximum holding times. [6] Device according to any one of the preceding claims, characterized by, that a whitelist of permissible target objects / registers with value ranges is stored and no write operations are allowed outside the defined ranges. [7] Device according to any one of the preceding claims, characterized by , that fault signaling means (10) are provided for bus- or network-side identification of a fault condition, in particular by means of OUT_OF_SERVICE, status / fault codes or dedicated diagnostic objects. [8] Device according to any one of the preceding claims, characterized by , that an override input (6) and / or a watchdog monitoring (7) is provided, which allow a local priority switching and decouple the control / regulation device (11) from interference in case of malfunction of the module. [9] Device according to any one of the preceding claims, characterized bythat audit-proof logs with timestamps are kept (audit trail) that contain at least key performance indicators, written values, priorities and error events. [10] Device according to any one of the preceding claims, characterized by , that a sensor / feedback interface exists for reading an actual switching / operating state and / or a relevant measured value and is used for plausibility checks and / or limit value monitoring. [11] Device according to any one of the preceding claims, characterized by that a real-time clock (RTC) and local storage / cache are provided for stand-alone operation without a cloud connection. [12] Device according to any one of the preceding claims, characterized by that the device is designed as a retrofit module for control cabinet mounting with multi-range power supply (e.g. 24 V DC / 230 V AC). [13] Arrangement for price-based influencing of operational parameters of an existing control / regulating device (11) of a technical plant, characterized by the combination of a device according to one of claims 1-12 and the existing control / regulation device (11), wherein the module influences at least one setpoint, one operating mode and / or one power / demand limit via the fieldbus or data network-based connection. [14] Arrangement according to claim 13, characterized by that the technical system is a refrigeration system of a food retail location and / or a refrigeration system of a logistics cold storage facility, whereby at least one temperature limit is monitored as a hard constraint and failsafe is triggered when approached. [15] Device or arrangement according to any one of the preceding claims, characterized bythat an interface to an energy service provider and / or metering point operator is provided for the receipt of price / flex signals and / or for the transmission of status / consumption data.