FANUC system grating ruler debugging technology

       With the development of science and technology, various intelligent detection components have also emerged. HEIDENHAIN has recently introduced a distance-coded reference with a distance-coded reference point marker. A linear measuring system with a distance-coded reference point marker eliminates the need to return a reference point to the machine and installs a deceleration switch and returns a fixed machine reference point, which provides a lot of convenience in practical use.
   I. Principle

      The principle of a linear measurement system with a distance-coded reference point marker is to use a grid marker comprising a standard linear and a distance-coded reference point marker channel running parallel to this, the distance between each set of two reference point markers is The same, but the distance between two adjacent reference point markers between the two groups is variable, and the distance of each segment is added with a fixed value, so the numerical control axis can determine the absolute position according to the distance, as shown in the figure. As shown below: (LS486C as an example)
    For example, moving from point A to point C, passing through point B in the middle, the system detects that 10.02 knows which reference point position the axis is now, and also moves from point B to point D, through point C in the middle, and from point C to point D in the system. The distance is 10.04 to know which reference point position the axis is now, so the absolute position of the machine can be obtained as long as the axis moves arbitrarily more than two reference points (20mm).
HEIDENHAIN's linear encoders have this function with "C" behind them, such as "LF183C, LS486C, LB382C".
Spain's FAGOR's linear encoders with "O" in the middle also have this function, such as "COV, COVP, FOP".

 II.  Application

 Applied in FANUC CNC system 0I-C.

1. Parameter setting (this function is the option function 0ic order number A02B-0310-J670 18I order number A02B-0284-J670)
(1).  1815#1 OPT 1815#2 DCL
       Scale ruler type: A linear scale with a distance coded reference point mark is selected.
       (When using a circular grating, 1815#1 #2 #3 should be set to 1)
(2). 1802#1 DC4
(3)  1821 Distance between two adjacent Mark1
       Linear encoder standard reference point marker grid spacing
(4)  1882 Distance between two adjacent Mark2
(5)  1883 The distance between the imaginary grating ruler origin and the reference point

  Parameter setting of HEIDENHAIN LB302C grating ruler.

Distance between two adjacent Mark1s 80mm
The distance between two adjacent Mark2s is 80.040mm
I want to set the parameters as follows: 1815#1 1 1815#2 1
1802#1 DCL is set to 0 using 3 reference points to detect homing
1821 80000 (minimum detection unit u)
1882 80040 (minimum detection unit u)
1883 Zeroing after power-on The machine will move 3 times to automatically calculate the coordinate position of the zero point. Fill in 1883 to establish a reference point. After the power is turned off, the power is turned on to perform the zero return operation. The axis is stopped 3 times (or 4 times, parameter 1802#1 is set to 1), and the absolute coordinates and machine coordinates of the position are automatically calculated according to the data fed back from the grating scale. . And the absolute coordinate and the mechanical coordinate of the axis are assigned, and the reference point can be established without completely ending the zero return operation. Because this method of zero return is not like incremental, it needs to return to zero after hitting the deceleration block in the whole process, and it does not record like position in absolute mode, and there is no need to return to zero. This kind of zero return only needs a short distance zero return operation, so it is called semi-absolute.

2. Operation

The first step is to set the parameters according to the above method (1883 first do not set)
Step 2: Confirm the absolute position of the machine.
Since the distance between the two reference point markers is variable, the system can accurately identify which reference point the axis is in and calculate the actual position, but this position may not be what you need. The machine tool reference point value, so there must also be a reference point offset parameter to participate in the calculation. This step can be completed by setting 1883#. In fact, the value set in 1883# is the distance from the first reference point in the measurement system to the machine reference point.

3. Troubleshooting (If you choose this type of ruler, be sure to select this function, otherwise it will not return to zero)
   1) The zero return operation cannot be performed. The speed of the zero return is the normal speed setting.
   2) Can't stop normally. No. 90 alarm. Is there any interference in the feedback signal of the scale?
   1 ruler feedback cable connection 2 ruler itself installation and ruler cleaning
   3) 417# alarm This parameter setting of the scale is correctly set according to the specifications of the scale. If the alarm still occurs, it can be solved according to the two methods described below. Check the source of the 280# troubleshooting problem in the system self-diagnosis. Check the contents of 352# in the system self-diagnosis, and according to the data displayed in 352#, follow the procedure described in the "Servo Motor Parameter Specification" 2.1.5 when the servo parameter setting illegal alarm occurs. 4) 445# alarm Soft disconnection alarm Mainly the installation of the grating head and the grating scale body can not meet the requirements, please pay attention to the installation requirements provided by the grating scale manufacturer, can also be solved by the following methods
2003#1 0 —〉1
2064 4 —>16 (or a multiple of 4)
5) 411# alarm The flying phenomenon occurs when moving. In the past, the hardware wiring A and *A, B and *B were changed. With the update of the servo software, modify 2018#0 RVRSE to 1.
to sum up
    CNC machine tools, especially large CNC machine tools, have a long moving distance of the CNC axis. After installing a linear measuring device with a distance coded reference point mark, it can bring great convenience in operation and use, such as faster returning to the reference point. In both directions, it can be operated; in some cases, such as a long lathe, because there is a center frame in the middle, it is inconvenient to return to the reference point in the Z-axis direction. Previously, only multiple deceleration switches and reference point markers could be used, but how It is a problem to deal with the pitch compensation of the CNC axis. This problem can be solved very well by using the linear scale of the intelligent reference point.


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