====== Command:UM ======

--> MS2000 or RM2000 syntax ^

^Format  |UM [axis]= ### …|
^Units    |Integer |
^Remembered |Using SS Z |

<--

--> Tiger syntax ^

^Format  |UM [axis]= ### …|
^Units    |Integer |
^Type    |Axis-Specific  |
^Remembered |Using [addr#]SS Z |

<--

== Unit Multiplier ==

Specifies the multiplier for most serial commands such as ''MOVE'' and'' WHERE''. Default for stages is 10000, which means 10000 units per millimeter or 0.1 μm/count. For rotary stages and micro-mirror devices the UM is 1000 corresponding to milli-degrees.  

The Unit Multiplier can be saved with the [[commands:saveset|SS Z command]]. 

<WRAP center round info 60%>
**Note:** The sign of the Unit Multiplier can be used to change the relative direction of motion for commanded moves, but using the [[commands:customa|CCA Z command]] is the recommended way to change the stage direction. 
</WRAP>

== Reply ==

If there are no errors, a positive reply of <wrap reply> :A </wrap>  is returned.

== For Clocked Position Devices ==

UM command has no effect if the axis is a Clocked Device like Filter Slider, Objective slider or Objective Turret. 

== Example ==
<asi> $ UM X=10000   
:A
$ UM X?
X=10000.000000 A
</asi>

As of Firmware version ''9.2l'' (for MS-2000) and ''3.18'' (for Tiger), when ''UM'' for a clocked Device is set to "1", the [[commands:where|WHERE (W) command]] prints the Axis position in millimeters instead of the slot position. The ''MOVE (M)'' command continues to work, while ''MOVREL (R)'' doesn't. This feature is meant for troubleshooting and diagnostic usage only and not meant for regular operation.  


{{tag>commands tiger ms2000}}