Number of position feedback pulses per motor revolution
1,000,000
NOTE
When both parameters Nos. 1874 and 1875 are set to 0, both parameters are assumed to be 1.
1880 Abnormal load detection alarm timer
[Input type] Parameter input [Data type] Word path [Unit of data] msec [Valid data range] 0 to 32767
This parameter sets the time from the detection of an unexpected disturbance torque until a servo alarm is issued.
When 0 is set, however, the specification of 200 msec is assumed.
1881 Group number when an unexpected disturbance torque is detected
[Input type] Parameter input [Data type] Byte axis [Valid data range] 0 to 32
Set the group number on each axis when an unexpected disturbance torque is detected.
When an unexpected disturbance torque is detected on an axis, only the movements on those axes that belong to the same group as the axis are stopped.
If 0 is set for an axis, the movement on the axis is stopped when an unexpected disturbance torque is detected on any other axis.
This parameter is valid when bit 5 (ANA) of parameter No. 1804 is set to 1.
[Example]
When the settings indicated below are made, and an unexpected disturbance torque is detected on the 6th axis, the movements on the 2nd axis, 4th axis, 6th axis, and 7th axis are stopped. When an unexpected disturbance torque is detected on the 4th axis, the movements on the 4th axis and the 7th axis are stopped.
Parameter No. 1881 Setting value
(1st axis) 1
(2nd axis) 2
(3rd axis) 1
(4th axis) 0
Parameter No. 1881 Setting value
(5th axis) 3
(6th axis) 2
(7th axis) 0
1882 Interval of mark 2 of a linear scale with absolute address reference marks
NOTE
When this parameter is set, the power must be turned off before operation is continued.
[Input type] Parameter input [Data type] 2-word axis [Unit of data] Detection unit [Valid data range] 0 to 999999999
Set the interval of mark 2 of a linear scale with absolute address reference marks.
1883
Distance 1 from the scale zero point to reference position (linear scale with absolute address reference marks) or distance 1 from the base point to reference position (linear scale with an absolute address
zero point)
NOTE
When this parameter is set, the power must be turned off before operation is continued.
[Input type] Parameter input [Data type] 2-word axis [Unit of data] Detection unit
[Valid data range] -999999999 to 999999999
1884
Distance 2 from the scale zero point to reference position (linear scale with absolute address reference marks) or distance 2 from the base point to reference position (linear scale with an absolute address
zero point)
NOTE
When this parameter is set, the power must be turned off before operation is continued.
[Input type] Parameter input [Data type] 2-word axis [Unit of data] Detection unit [Valid data range] -999 to 999
When a linear scale with absolute address reference marks is used, set the distance from the scale zero point to reference position in parameter Nos. 1883 and 1884).
Distance from the zero point to the reference position of a linear scale
= No. 1884 1,000,000,000 + No. 1883
The scale zero point represents a point where mark 1 and mark 2 match. Usually, this point is a virtual point that does not physically exist on the scale. (See the Fig. 4.18 (a).) If the reference position is placed in the + direction when viewed from the scale zero point, set a positive value. If the reference position is placed in the - direction when viewed from the scale zero point, set a negative value.
Mark 1 Mark 2 Mark 1 Mark 2
Zero point of encoder Encoder end Reference position
……..
When an encoder as shown Fig. 4.18 (b) is used with an IS-B, millimeter machine:
20.000 19.980 9.940 10.060 9.960 10.040 9.980 10.020
Scale zero point + direction Reference position - direction
Parameters
No.1821 (interval of mark 1) = 20000 No.1882 (interval of mark 2) = 20020
No.1883 (reference position) = position of point A + 5.000
= distance between A and B/(mark 2 mark 1) mark 1 + 5000
= 9960/(20020-20000) 20000 + 5000
= 9965000
= -9965000 (the reference position is on the negative side)
Fig. 4.18 (b)
[Setting parameter No. 1883]
When it is difficult to measure the distance from the scale zero point to the reference position (parameter No. 1883), the method described below can be used to find the distance.
<1> Set parameter No. 1815 to enable this function.
Set an appropriate value in parameter No. 1821 and No. 1882.
Set 0 in parameter No. 1240.
Set 0 in parameter No. 1883 and No. 1884.
<2> At an appropriate position, establish a reference position.
(As a result, the machine coordinate represents the distance from the scale zero point to the current position.)
<3> By jog feed or handle feed, place the machine at the accurate reference position.
<4> In parameter No. 1883, set the machine coordinate of that time converted to the detection unit (machine coordinate CMR).
<5> If necessary, set parameter No. 1240.
When a linear scale with an absolute address zero point is used, set the distance from the base point to the reference position in parameter Nos. 1883 and 1884. The base point is a point at a scale end as shown Fig. 4.18 (c). point, set a positive value; if the reference position is located in the negative direction, set a negative value. Set the value by following the steps explained below.
<1> Set bit 1 (OPT) of parameter No. 1815 , bit 2 (DCL) of parameter No. 1815, and bit 3 (SDC) of parameter No. 1818 to enable this function.
Set 0 in parameter No. 1240.
Set 0 in parameter Nos. 1883 and 1884.
<2> At an appropriate position, establish a reference position.
(Consequently, the machine coordinate value indicates the distance from the base point to current position.)
<3> By jog feed or handle feed, place the machine at the accurate reference position.
<4> In parameters Nos. 1883 and 1884, set the machine coordinate of that time converted to the detection unit (machine coordinate CMR).
If necessary, set parameter No. 1240.
NOTE
1 Set parameter Nos. 1883 and 1884 so that the distance from the scale zero point (for a linear scale with absolute address reference marks) or the base point (for a linear scale with an absolute
address zero point) to the reference position is within the range from -999,999,999,999 to +999,999,999,999. If a value beyond this range is set, an alarm DS0016 or DS1448 is issued.
2 The scale area on the scale cannot be extended across the scale zero point or base point. Make parameter settings not to cause the scale area to extend beyond the scale zero point or base point.
1885 Maximum allowable value for total travel during torque control
[Input type] Parameter input [Data type] Word axis [Unit of data] Detection unit [Valid data range] 0 to 32767
Set a maximum allowable cumulative travel value (error counter value) during torque control. If the cumulative travel value exceeds the set value, the servo alarm SV0423 is issued.
NOTE