Emerson FM-3 - Manual (Page 62)

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FM-3 Programming Module Reference Manual
Software Travel Limits
Software Travel limits can be used to limit machine travel. They are often setup inside the
hardware travel limits to add another level of security or protection from exceeding the
machines travel limits. The FM-3 module constantly monitors the feedback position, and if
this position exceeds the values entered for Software Travel Limit + or -, then the drive will
decel to a stop. Software Travel Limits are not functional unless the AbsolutePosnValid
source is active. AbsolutePosnValid is active upon successful completion of a home or the
DefineHome destination is activated.
To recover from a software travel limit, a jog may be commanded in the opposite direction of
travel. For example, if a software travel limit - is hit, then the axis can be jogged in the +
direction.
Software Travel Limit +
If the absolute position is greater than or equal to this value the Software Travel Limit Plus
Active source shall activate.
A rising edge occurs when the absolute position is greater than or equal to the parameter
Software Travel Limit +. A falling edge will be generated as soon as the above is not true.
Software Travel Limit -
If the absolute position is less than or equal to this value the Software Travel Limit Minus
Activate shall activate.
A rising edge occurs when the absolute position is less than or equal to the parameter
Software Travel Limit -. A falling edge will be generated as soon as the above is not true.
Rotary Group
Rotary Rollover Check Box
Check this box to enable (or disable if not checked) the rotary rollover feature.
Rotary Rollover
This parameter is used in rotary applications and determines the position at which the internal
position counter will be reset to zero.
Example:
The user has a rotary table application with distance user units of degrees, 360.00 degrees/1
rev. The Rotary Rollover would be set to a value of 360°.
The motor is traveling in the positive direction. As the feedback position reaches 359.999 and
continues on, the feedback position will reset (or roll-over) to zero. If the motor changes
direction and travels in the negative direction, the position will rollover at 0 to 359.999
degrees and count down. The resolution of the rotary rollover point is determined by the