| Parameter Name | Units | Type | Default | Description |
| X | long | 1 | center x coordinates? | |
| XP | long | 1 | center x' coordinates? | |
| Y | long | 1 | center y coordinates? | |
| YP | long | 1 | center y' coordinates? | |
| ONCE_ONLY | long | 0 |
compute centering offsets for first beam only, apply to all? | |
| ON_PASS | long | -1 | If nonnegative, do centering on the nth pass only. | |
| GROUP | string | NULL | Optionally used to assign an element to a group, with a user-defined name. Group names will appear in the parameter output file in the column ElementGroup |