LINK Systems OmniLink II Press Automation Control - Manual (Page 60)

August 30, 2002 Manual Version 1.0 4.11
Thus, regardless of whether you have a negative or positive misalignment of encoder to
crankshaft, the Encoder Offset to manually enter when you calibrate the resolver with the
slide at the top of stroke position is determined by the relation:
Encoder Offset = 360 0 – Display Angle (with current Encoder Offset setting of 0)
4. Verify that the angle display changes to 0
0 after you press the Set Zero softkey or manually enter an
offset. Manual entry of numbers between 0 0 –9 0 and 350 0 –359 0 is allowed. If you have manually
entered the wrong offset and the angle display doesn’t change to 0 0 , press the CLEAR key while
Offset Encoder is selected to return the offset to 0 and then manually enter the correct offset angle.
Method 2. Slide at Bottom of Stroke
1. Inch the press to position the crankshaft within no more than a couple of degrees of bottom dead
center 180 0 (slide at bottom of stroke). This is important because the system uses the crank angle as
its absolute reference and will assume that the crankshaft position is at 180 o degrees when you
calculate and manually enter the Encoder Offset. If the crankshaft is actually 5 0 from bottom dead
center when you manually enter an offset, as described in the following steps, you will incorporate a
5
0 error into the angle indication of the OmniLink II Operator Terminal. Make sure the Encoder
Offset setting shown on the screen is 0. If it is a value other than zero, manually enter a setting of
zero before going to the next step.
2. When you have positioned the crankshaft as closely as possible to bottom dead center (use of a dial
indicator gage between bolster and slide may be a useful tool to accurately determine bottom of
stroke), read the angle display on the OmniLink II Operator Terminal. The number displayed must
be within +/-10
0 of 180 0 , i.e., it must be between170 0 and 190 0 . This is because a maximum
misalignment of resolver to crankshaft of +/-10 0 can be corrected by the Encoder Offset function. If
the displayed angle is less than 171 0 or more than 190 0 , you must manually decouple the
resolver/encoder from the crankshaft and recouple it within the required angle range.
3. You must determine the required Encoder Offset to manually enter. The Set Zero softkey must not
be used when determining offset in the bottom of stroke position. Determine the Encoder Offset
angle to use as follows. Read the value on the angle display of the operator terminal with the
crankshaft at BDC.
a) If the angle display indicates a value between 171
0 and 179 0 , calculate the Encoder Offset as:
Encoder Offset = 180
o – Display Angle (with Encoder Offset setting of 0)
b) If the angle display indicates a value between 181 0 and 190 0 , calculate the Encoder Offset as:
Encoder Offset = 540 0 – Display Angle (with Encoder Offset setting of 0)
4. Use the number keys to key in the Encoder Offset you have calculated and press the ENT (Enter)
key when finished. The operator terminal angle display should now read 180 0 . If not, you may have
calculated the wrong offset angle or tried to offset a misalignment of more than +/- 10 0 . Manually
enter 0 as the Encoder Offset and repeat this procedure.