Two parallel but quasi independent Block Programs, one for the load and the other for the temperature, define Thermo-Mechanical Cycling. Each block may consists of several stages. In the case of temperature block, each stage is defined by starting and finishing times and corresponding temperatures. In the case of load block, each stage can be either ramp - hold or cyclic. Although each stage of the block programme for load and temperature can be set independent of each other, provision is made to compel load to wait for the temperature to be within a given tolerance band. The combined block can be repeated as many times as required or until any one of a number of "target" end of test criteria is met. While the combined temperature / load stages are in progress DCPD readings will be carried out at regular intervals.