A method of controlling a plurality of DC power supplies (189, 289, 389, 689, 789, 889) to change a respective DC offset voltage applied to each of a plurality of components (191, 291, 391, 691, 791, 891) for manipulating charged particles, wherein each DC power supply corresponds to a respective component, and wherein the method includes, whilst the same AC voltage waveform (181, 681) is being applied to each of the components (191, 291, 391, 691, 791, 891): for each DC power supply, respectively: controlling the DC power supply (189, 289, 389, 689, 789, 889) to produce an initial DC offset voltage that is applied to the component (191, 291, 391, 691, 791, 891) corresponding to the DC power supply via a link that causes the DC offset voltage at the component (191, 291, 391, 691, 791, 891) to lag behind the DC offset voltage produced by the DC power supply (189, 289, 389, 689, 789, 889) when the DC offset voltage produced by the DC power supply (189, 289, 389, 689, 789, 889) is changed; then controlling the DC power supply (189, 289, 389, 689, 789, 889) to produce an overdrive DC offset voltage that is applied to the component (191, 291, 391, 691, 791, 891) corresponding to the DC power supply via the link for a predetermined period of time; then, after the predetermined period of time has elapsed controlling the DC power supply (189, 289, 389, 689, 789, 889) to produce a target DC offset voltage that is applied to the component (191, 291, 391, 691, 791, 891) corresponding to the DC power supply via the link, wherein the target DC offset voltage is between the initial DC offset voltage and the overdrive DC offset voltage; wherein the method includes, for each DC power supply, respectively: choosing the overdrive DC offset voltage such that the DC offset voltage at the component (191, 291, 391, 691, 791, 891) corresponding to the DC power supply (189, 289, 389, 689, 789, 889) is at, or is within a predetermined threshold of, the target voltage at the end of the same predetermined period of time, wherein the DC offset voltage at each of the plurality of components is made to reach a respective target DC offset voltage at the end of the same predetermined period of time. for each DC power supply, respectively: controlling the DC power supply (189, 289, 389, 689, 789, 889) to produce an initial DC offset voltage that is applied to the component (191, 291, 391, 691, 791, 891) corresponding to the DC power supply via a link that causes the DC offset voltage at the component (191, 291, 391, 691, 791, 891) to lag behind the DC offset voltage produced by the DC power supply (189, 289, 389, 689, 789, 889) when the DC offset voltage produced by the DC power supply (189, 289, 389, 689, 789, 889) is changed; then controlling the DC power supply (189, 289, 389, 689, 789, 889) to produce an overdrive DC offset voltage that is applied to the component (191, 291, 391, 691, 791, 891) corresponding to the DC power supply via the link for a predetermined period of time; then, after the predetermined period of time has elapsed controlling the DC power supply (189, 289, 389, 689, 789, 889) to produce a target DC offset voltage that is applied to the component (191, 291, 391, 691, 791, 891) corresponding to the DC power supply via the link, wherein the target DC offset voltage is between the initial DC offset voltage and the overdrive DC offset voltage; controlling the DC power supply (189, 289, 389, 689, 789, 889) to produce an initial DC offset voltage that is applied to the component (191, 291, 391, 691, 791, 891) corresponding to the DC power supply via a link that causes the DC offset voltage at the component (191, 291, 391, 691, 791, 891) to lag behind the DC offset voltage produced by the DC power supply (189, 289, 389, 689, 789, 889) when the DC offset voltage produced by the DC power supply (189, 289, 389, 689, 789, 889) is changed; then controlling the DC power supply (189, 289, 389, 689, 789, 889) to produce an overdrive DC offset voltage that is applied to the component (191, 291, 391, 691, 791, 891) corresponding to the DC power supply via the link for a predetermined period of time; then, after the predetermined period of time has elapsed controlling the DC power supply (189, 289, 389, 689, 789, 889) to produce a target DC offset voltage that is applied to the component (191, 291, 391, 691, 791, 891) corresponding to the DC power supply via the link, wherein the target DC offset voltage is between the initial DC offset voltage and the overdrive DC offset voltage; wherein the method includes, for each DC power supply, respectively: choosing the overdrive DC offset voltage such that the DC offset voltage at the component (191, 291, 391, 691, 791, 891) corresponding to the DC power supply (189, 289, 389, 689, 789, 889) is at, or is within a predetermined threshold of, the target voltage at the end of the same predetermined period of time, wherein the DC offset voltage at each of the plurality of components is made to reach a respective target DC offset voltage at the end of the same predetermined period of time.