Process control system, process control apparatus and program update method

A process control system, comprising:

• a first process control apparatus;
• and
• a second process control apparatus,
• wherein the first process control apparatus comprises:
• a first program execution unit configured to execute a non-update target program which is not an update target and an update target program which may be the update target, and
• a first program update manager configured to pause the non-update target program based on a pause request from an outside, and to transfer a context of the non-update target program to the second process control apparatus, and
• wherein the second process control apparatus comprises:
• a second program execution unit configured to execute the non-update target program which is not the update target and an update target program after update, and
• a second program update manager configured to restore a context of the non-update target program by using the context transferred from the first program update manager, to initialize a context of the update target program, and to cause the second program execution unit to resume the non-update target program and the update target program, based on a resuming request from the outside.