Hi Brian.
They get out of sync because you haven't installed the mechanical stops (you need mechanical stops in both the fully open and the fully closed position of the gate).
The way most control boards for swing gates work is like a blind man using a stopwatch. The board knows nothing about the actual position of the gate leaf/leaves. When you program it, it is like instructing the blind man that, when you say "open the gate" he has to press button A for X seconds (ie duration of opening movement with normal speed) and then press button B for Y seconds (ie duration of opening movement with slow speed) etc.
Even if one programs the operating times with extreme precision, the exact length of the leaf travel is a bit random (it depends on what resistance it will encounter each time, if the wind is for or against the movement etc etc). If you don't have mechanical stops limiting the end-travel, even the slightest errors may accumulate and the result will be that the gate movement will be visibly out of sync.
The simple, standard solution is installing mechanical stops at the fully open and fully closed positions of the gate leafs to restrict movement AND, when programming the control board, adding a little extra operator working time. In this way, the gate leaf will reach the mechanical stop and will keep pressing against the stop for that little extra time (for normal gates it is usually 2-4 secs) before it stops.
In this way, it is almost impossible for the gate to get out of sync even if it is slightly delayed by some opposing strong wind or if we disengage the operator for manual movement and then re-engage it at a random position or if the power is cut while the gate is in an intermediate position (in this case, when power is restored, the control board has lost its clue on where the leaf is/leaves are).
Another benefit of having mechanical stops is that it protects the gate operators, when they are disengaged (when the manual release is activated). Without the stops you could, manually, get the leaf/leaves in a position where the operator(s) will exert little to no torque on it/them, making beginning of powered movement impossible. An even worse problem, when not having anything else to stop the opening movement of the gate, is that, if you slam open the gate, it will hammer the operator which may very well damage it (especially if the gate is heavy and/or wide).
You should not worry about the extra time the operators will be working at the end-of-travel: swing gate operators are designed with that in mind and will not be damaged however long they keep pushing a stopped leaf. However, you would like to keep this extra time in the few seconds range. One of the reasons is that the gate is not considered, by the control board, open or closed until the programmed time expires. Therefore if the gate is closed but the motor is still working, if you engage the closing photocells the gate will open again (for you "closed" means that the gate is at a certain position but for the control board "closed" means that a certain time has elapsed).
To recap, you MUST install mechanical stops at the fully open and fully closed positions of you gate leaf/leaves and add a little extra working time when programming the duration of the movements.
PS: most control boards for swing gate operator, in normal operation, either don't sense obstructions (resistance to movement indicated by a sudden increase in current through the motor or stop of travel indicated by an encoder) at all or don't sense them during the slow movement (close to end-of-travel) phase. Some control boards, use obstruction sensing only when in programming mode (in order to automatically discover where the mechanical stops are) but, in normal working mode, work as above.
They get out of sync because you haven't installed the mechanical stops (you need mechanical stops in both the fully open and the fully closed position of the gate).
The way most control boards for swing gates work is like a blind man using a stopwatch. The board knows nothing about the actual position of the gate leaf/leaves. When you program it, it is like instructing the blind man that, when you say "open the gate" he has to press button A for X seconds (ie duration of opening movement with normal speed) and then press button B for Y seconds (ie duration of opening movement with slow speed) etc.
Even if one programs the operating times with extreme precision, the exact length of the leaf travel is a bit random (it depends on what resistance it will encounter each time, if the wind is for or against the movement etc etc). If you don't have mechanical stops limiting the end-travel, even the slightest errors may accumulate and the result will be that the gate movement will be visibly out of sync.
The simple, standard solution is installing mechanical stops at the fully open and fully closed positions of the gate leafs to restrict movement AND, when programming the control board, adding a little extra operator working time. In this way, the gate leaf will reach the mechanical stop and will keep pressing against the stop for that little extra time (for normal gates it is usually 2-4 secs) before it stops.
In this way, it is almost impossible for the gate to get out of sync even if it is slightly delayed by some opposing strong wind or if we disengage the operator for manual movement and then re-engage it at a random position or if the power is cut while the gate is in an intermediate position (in this case, when power is restored, the control board has lost its clue on where the leaf is/leaves are).
Another benefit of having mechanical stops is that it protects the gate operators, when they are disengaged (when the manual release is activated). Without the stops you could, manually, get the leaf/leaves in a position where the operator(s) will exert little to no torque on it/them, making beginning of powered movement impossible. An even worse problem, when not having anything else to stop the opening movement of the gate, is that, if you slam open the gate, it will hammer the operator which may very well damage it (especially if the gate is heavy and/or wide).
You should not worry about the extra time the operators will be working at the end-of-travel: swing gate operators are designed with that in mind and will not be damaged however long they keep pushing a stopped leaf. However, you would like to keep this extra time in the few seconds range. One of the reasons is that the gate is not considered, by the control board, open or closed until the programmed time expires. Therefore if the gate is closed but the motor is still working, if you engage the closing photocells the gate will open again (for you "closed" means that the gate is at a certain position but for the control board "closed" means that a certain time has elapsed).
To recap, you MUST install mechanical stops at the fully open and fully closed positions of you gate leaf/leaves and add a little extra working time when programming the duration of the movements.
PS: most control boards for swing gate operator, in normal operation, either don't sense obstructions (resistance to movement indicated by a sudden increase in current through the motor or stop of travel indicated by an encoder) at all or don't sense them during the slow movement (close to end-of-travel) phase. Some control boards, use obstruction sensing only when in programming mode (in order to automatically discover where the mechanical stops are) but, in normal working mode, work as above.
