Program controllers carry out control per the target setpoints (SP) in a single program pattern. However there are many cases where control must be based on a pattern in conjunction with another pattern of setpoints. One example of this is with temperature/humidity control. This type of control can, of course, be handled by using two program controllers, but this is more costly and troublesome in terms of synchronizing the time axes of the two units. The Yokogawa UP750/UP550 includes a standard function allowing you to enter a second pattern and output analog signals in a single parameter setup operation.

This pattern (PT2. G) needs to be turned ON to make this function enabled, so that the SP values can include another program pattern under a common time axis. Because the SP pattern can be transmitted with a 4–20 mA signal, two systems can be controlled by sending the second pattern as a set of target values to another constant value controller.

Setting up the second pattern is easy.

With the normal 1 pattern, the following repeats.

When parameter (PT2. G) is turned ON, parameter (TSP2) to set a second pattern of target setpoints can be also displayed, resulting in:

The instruments supporting the function are the UP750 and UP550. Note that the function may be unavailable depending on the controller mode. Furthermore, since the scaling of patterns 1 and 2 can be set differently, a configuration such as [pattern 1 for temperature of 0.0–1000.0°C], and [pattern 2 for flow volume of 0.0–500.0 liters/hour] is possible.