Description
FOXBORO P0973LQ Switch
FOXBORO P0973LQ (also labeled Evo Control Network Power) is a network power module in the Foxboro (now part of Schneider Electric’s Invensys/Evo series) DCS control system. Its core function is to provide stable DC working power for switches, controllers, and I/O slave devices in the Evo control network. It is a key power supply node in the system infrastructure layer.
core positioning
P0973LQ itself does not execute any control algorithms and does not process process process data. It is a power module installed inside the control cabinet, which converts external AC power into the DC voltage required by the control network, and supplies it to switches, communication modules, and I/O cards within the same rack or network segment. In the Evo DCS architecture, it ensures the continuity of power supply and electrical isolation of the entire control network, which is the underlying guarantee for stable network operation.
Electrical Characteristics
The input voltage supports 100-240V AC (50/60Hz) and is also compatible with the DC input range. The output is the low-voltage DC power supply required by the system, and the maximum output current meets the simultaneous power supply requirements of multiple network devices. The module implements electrical isolation between the input and output sides, effectively blocking the impact of on-site grounding circuits and transient interference on the control network. Equipped with overvoltage protection, overcurrent protection, and surge protection. Automatically detect the electrical ID of the module when powered on, and refuse to enter the running state when it does not match the system configuration, to prevent network equipment damage caused by mismatching.
Physical specifications
Weighing approximately 2kg, standard DIN rails or panels are installed inside the control cabinet. The onboard LED indicator lights display real-time power status and fault conditions, making it easy to quickly locate problems on site. Supports hot swapping and can be replaced without interrupting the operation of Evo control network when the system is powered on. The working temperature meets the environmental requirements of the industrial control room.
Role in the system
P0973LQ is a supporting power supply for Foxboro Evo DCS (next-generation open industrial system OIS), and together with Evo series controllers, Evo network switches (such as P0973LN and other 24 port fiber management switches), and Evo I/O modules, it forms a complete control station. During system expansion or maintenance, P0973LQ can provide plug and play power access for newly added network devices without the need to re plan the power supply circuit.
Typical Applications
Mainly used for brownfield sites that are still running Foxboro I/A Series or have been migrated to Evo platform, including thermal power and gas turbine control in the power industry, refining equipment and pipeline transportation in the petrochemical industry, rolling mill and continuous casting control in the metallurgical industry, as well as continuous process industries such as water and papermaking. In these scenarios, it provides uninterrupted clean power to the control network, ensuring deterministic synchronization of operator station HMI screen updates, alarm propagation, and historical data recording with the on-site control layer.
Explanation on the Naming of ‘Switch’
Some materials classify P0973LQ as an “Ethernet switch”, which is a confusion of different sub models under the same P0973 series. P0973LN is clearly a 24 port fiber management switch, while the precise function of P0973LQ is Evo to control network power. The two have different roles in the Evo system: LQ is responsible for power supply, while LN is responsible for data exchange. When replacing, it is necessary to confirm the suffix of the material number to avoid mismatches.
