Adjust the gain of the signal amplifier to get ]-10V, +10V[ at the input of the ADC, range= 001, 002, 004,...128, 256.
Gain adjustment: in the ARC scanner MEDM window, click (right button for Arun Saha, left one in general!) on the gain command button located close to the plot of the profile of the scanner you want to adjust. Then select a gain and release the mouse.
After a scan:
-Select higher gain if the rightmost peak is 
3V (in absolute value)
-Select lower gain if the scanner saturates. To know if the scanner saturates, do not believe the MEDM plot (on which several adjacent channels are averaged), trust the red diode associated to each scanner (close to the plot). If you want to know what these diodes look like, click on "edit" on the MEDM access window: you will see the diodes. Then return to "execute".
Start with the gains (dispersive case):
| scanner | gain |
| #1 | 4 |
| #2 | 8 |
| #3 | 32 |
| #4 | 32 |
Note that in dispersive mode the beam is dispersed at scanners #3 and #4 locations, so these scanners need a higher gain than #1 and #2.
To zoom on a peak, change the MEDM parameters of the window ("edit"):
-first determine the range (in mm) on which you want to zoom
-on the MEDM access window, push on "edit"
-on the ARC window, click anywhere inside the plot you want to change
-on the "Resource Palette", go down to "Axis Data", select it
-on the "Cartesian Plot Axis Data", in the "X Axis" part (X means horizontal), change "Axis Range" from "auto-scale" to "user-specified", then edit "Minimum Value" and "Maximum Value" to specify the horizontal range you want to look at, the unit is mm. If you used the "edit" facility of MEDM, it will suggest that you save the changes when killing the window. Do not save the changes!
-on the MEDM access window, push on "execute"
Short-cut: push on the right button while the cursor is inside the plot, you will access directly to the MEDM axis data menu Other MEDM tricks (may depend on the version of MEDM you are running):
-Control+middle button+vertical drag will scale the plot up or down
-Shift+middle button+drag will translate the plot.