The initial release of IPA drive/controller firmware 4.40 adds new functionality to the HLBIT command that assigns limit and home inputs.
This extension was added to ACR9xxx firmware in firmware version 1.41 (2.41 for 9600).
The original implementation of HLBIT is still supported for backwards compatibility.
example : HLBIT X3 or AXIS0 HLBIT 3
Input 3 is the positive limit, Input 4 is negative limit, Input 5 is home.
The user was only allowed to designate the positive limit, the next two consecutive bits were automatically assigned as negative limit and home.
HLBIT X(1,3,5) sets positive, negative, and home bits in that order. If any bits are out of range, the whole command is rejected. The second and third numbers are optional resulting in automatic assignment of next bit.
HLBIT X(1) sets positive, negative, and home bits to 1, 2, 3 respectively.
HLBIT X(1,3) sets positive, negative, and home bits to 1,3,4 respectively.
P12420 still displays positive limit bit number
P12437, P12438, P12439 display positive, negative and home bit numbers respectively.
(Note these are read-only parameters.)
Home to Limit
This new syntax also allows homing to a limit. If the home limit is the same as an end of travel limit, then the controller will home to that limit when the JOG HOME command is issued.
There are two differences from standard homing to prevent moving beyond end of travel limit.
1. If Home backup is enabled and home is also an end of travel limit, the user's choice of active edge is ignored. Instead the active edge will always the inside edge, the same edge that causes hard limit deceleration.
For the positive limit, this is the negative edge, for the negative limit, this is the positive edge.
2. When the combined home/EOT limit is hit, the hard limit deceleration value will be used instead of the jog deceleration.
The user's choice of final direction and final approach speed are still used.