Omron TJ1-DRT Hardware Reference Manual page 15

System philosophy
CPU tasks
The operations executed in each CPU task are:
CPU task Operation
First CPU task Motion Sequence
Low priority process
Second CPU task High priority process
Third CPU task Motion Sequence (only if SERVO_PERIOD=0.5ms)
LED Update
High priority process
Fourth CPU task External Communications
Program
A program is a piece of BASIC code.
Process
Is a program in execution with a certain priority assigned. Process 0
to 12 are Low priority processes and Process 13 and 14 are High
priority processes. First the process priority, High or Low, and then
the process number, from high to low, will define to which CPU task
the process will be assigned.
HARDWARE REFERENCE MANUAL 15