In a control system, a ratio relay is primarily used to:

A ratio relay is designed to control multiple actuators in a way that maintains specific proportional relationships between different variables in a control system. This is particularly useful in applications where you need to ensure that two or more processes or parameters operate in harmony to achieve the desired operational efficiency or performance.

For example, in systems where the output of one actuator affects another actuator, a ratio relay can adjust the outputs of the actuators to maintain a defined ratio. This means that if one actuator increases its flow or output, the ratio relay will correspondingly adjust the output of the second actuator to maintain the ratio set by the system. This is crucial in processes such as mixing, where the correct proportions of different materials need to be maintained for optimal performance or safety.

Understanding this function of a ratio relay is essential for effective control system design, as it ensures that the system operates within specified limits, reinforcing the importance of maintaining correct sequencing and proportional control among actuators for successful operation.