RMC 150 Memory

I need more space for variables. I have used most of the Variable Table and need another 560 registers. I’m using these to pass data between a PC and an SLC 5/05. Are ther any other registers I can access?


The short answer is no.

The long answer is that if you are really, really desperate, you may be able to. It’s convoluted and will cause some grief. It also depends on what you need to do with the values. You may be better off storing more data in the PLC.

The two available places are the curve data and the variable initial variables.

The good news is that you can store more than 200,000 data points here. The bad news is all the rest. To store data in the curve data area, you need to create a curve by writing data points along with other information, which requires some programming. Then, extracting the data is not real straight forward, because curves are not internally stored in a nice, easy-to-read manner. However, if you create a curve with an x-interval of 1.0, then you can relatively easily extract the data later using the CRV_INTERP_Y function, which allows you to get any data point you want.

Variable Initial Value
If you set a variable to Retentive, the current value will always be stored in non-volatile memory. That leaves the Initial Value kind of unused. You can write and read to the Initial Value somwewhat separately from the current value. However, when you write to the Initial Value, the Current Value becomes set to the Initial Value. So, you can use this method if you always first write to the Initial Value, then write to the Current Value.