Detailed Description of Trend
Trend data is actual logged from a West Fraser installation. The first trend is for one log with about a 2 sec duration in the cut. Saw-ADD speed control was in affect with a 10% increase in feed speeds which was previously not achievable.
As the pressure on the front of the saw increases from 14.28 lbs to only 39 lbs, the gained differential increases to 78 lbs, well above the limit of 40 lbs in orange. This is then used to reduce speed, allowing the pressure to decrease. The differential comes to a peek and cycles back down while the pressure on the front of the saw only reaches a peek. The front pressure then starts to decrease indicating that the saw has started to steer back to the cut line causing the differential to go in the negative direction from where it started.
This trend also shows a low resolution blade deviation signal from an inductive proximity sensor on the top guide (shown in red) which has the opposite polarity (negative towards the guide because distance is decreasing as pressure is increasing). The deviation, which immediately goes to an offset of about -5 thousandths of an inch at the beginning of the log, increases only 7 thou
and lags behind the pressures, even farther behind the pressure differential.
Trend data is actual logged from a West Fraser installation. The first trend is for one log with about a 2 sec duration in the cut. Saw-ADD speed control was in affect with a 10% increase in feed speeds which was previously not achievable.
As the pressure on the front of the saw increases from 14.28 lbs to only 39 lbs, the gained differential increases to 78 lbs, well above the limit of 40 lbs in orange. This is then used to reduce speed, allowing the pressure to decrease. The differential comes to a peek and cycles back down while the pressure on the front of the saw only reaches a peek. The front pressure then starts to decrease indicating that the saw has started to steer back to the cut line causing the differential to go in the negative direction from where it started.
This trend also shows a low resolution blade deviation signal from an inductive proximity sensor on the top guide (shown in red) which has the opposite polarity (negative towards the guide because distance is decreasing as pressure is increasing). The deviation, which immediately goes to an offset of about -5 thousandths of an inch at the beginning of the log, increases only 7 thou
and lags behind the pressures, even farther behind the pressure differential.
The second trend is a zoom in showing a delta time of 152 ms for the front sensor pressure and the deviation to peek and start to decrease. The differential (purple) crossed the limit of 40 lbs. only 44 ms after the increase started and 104 ms before the front sensor (blue) only came close to the limit. The blade deviation from the top guide only increased by 7 thou in the same time.
It should also be noted that this machine has a top head which allows the top guide to run very close to the controlled top chipped face of the log. Without a top head the top guide must run much higher above the log and therefore is not as accurate.
It should also be noted that this machine has a top head which allows the top guide to run very close to the controlled top chipped face of the log. Without a top head the top guide must run much higher above the log and therefore is not as accurate.
