Rockwell Automation 1746-QS,D17466.19 SYNCHRONIZED AXES MODULE - Manual (Page 35)

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Publication 1746-6.19 March 1998
| ATTENTION: When hydraulic system power is lost, your ladder logic is responsible |
| for ensuring that valve null and integrator sum do not wind up if the axis is |
| out of position. If wind up is allowed, the axis will move unexpectedly when |
| hydraulic system is restored. Typically, the preferred method is to: |
| – issue a Kill (“K”) command when the pump goes off to disable |
| valve null and integrator wind up |
| – issue a Go (“G”) command to current position or known target when |
| the pump goes on to re-enable the integrator and null with values |
| from before the Halt was issued |
| This should minimize unexpected motion when hydraulic power is restored. |
| |
| Also, your ladder logic must lock out any movement commands such as Go or Jog |
| when the axis is stopped due to loss of hydraulic power. |
| |
| Valve drive power |
| and pumps are ON, |
| electronic servo |
| valve is enabled, Oneshot |
| blocking valves open Storage |
| HYDRAULICS_OK BIT AXIS1_COMMAND |
| B3:0 B3:2 +MOV–––––––––––––––+ |
|––––––––]/[–––––––––––––––––––[OSR]–––––––––––––––––––––––––+MOVE FILE +––|
| 2 0 |Source 75 | |
| | 75<| |
| |Dest O:2.5 | |
| | 71<| |
| +––––––––––––––––––+ |
| Valve drive power |
| and pumps are ON, |
| electronic servo |
| valve is enabled, Oneshot |
| blocking valves open Storage |
| HYDRAULICS_OK BIT AXIS1_COMMAND |
| B3:0 B3:2 +MOV–––––––––––––––+ |
|––––––––] [–––––––––––––––––––[OSR]–––––––––––––––––––––––––+MOVE FILE +––|
| 2 1 |Source 80 | |
| | 80<| |
| |Dest O:2.5 | |
| | 71<| |
| +––––––––––––––––––+ |
Running Synchronized Axes
In Command-mode word (O:e.0, 8, 16, or 24 for axes 1, 2, 3, or 4):
•
select “Always Active” for the Integrator Mode
(Bits 2 and 3 must both be reset to zero.)
•
assign the same Synch A or B to all axes that are synchronized
(Bits 4, 5: Each of the synchronized axes must have the same bit set.)
The axis that moves the farthest is the master for module computations.
Speed values that you entered for shorter-run axes may not be achieved,
because all synchronized axes must reach the final position at the same
time. If one of the synchronized axis faults (stops), the others stop, also.
The module uses the master axis to compute axis decels so all stop at
the same point.
You may apply the above considerations to the previous ladder logic
example, Back and Forth Motion with State-machine Logic
(Programming for Automatic Operation).