A program can call PLIDUMP from anywhere in the program, but the normal method of debugging is to call PLIDUMP from an ON-unit. Because continuation after the dump is optional, the program can use PLIDUMP to get a series of dumps while the program is running.
You can use the DD:plidump environment variable to specify where the PLIDUMP output should be located, for example:
set dd:plidump = d:\mydump;
In your PLIDUMP specification, you cannot override other options such as RECSIZE. The default device association for the file is stderr:.