Changing DX200 Robot Soft Limits

Introduction

The Axis Soft Limits of DX200 robots are set in the controller when it is first Initialized.  It is possible to further restrict the Limits by editing them on the ROBOT -> SOFTLIMIT SETTING screens.  In order to increase the Limits beyond the values established at Initialization parameters must be adjusted.

Details

Several DX200 robot models are mechanically identical yet received different Axis Soft Limit values depending on how they are Initialized.  An example is the MA1440/MH12.  When Initialized as an MH12 the T-axis Soft Limit has a range of +/- 360 degrees (See Figure 1). 

Figure 1: MH12 Axis Soft Limit Settings

When Initialized as an MA1440 the T-axis Soft Limit has a range of +-210 degrees (See Figure 2). This is due to limits on the torsion rating of some torch cables.

Figure 2: MA1440 Axis Soft Limit Settings

It is possible to further reduce the Soft Limits by editing them on the SOFTLIMIT SETTING screens either by entering new degree or pulse values.  If a larger value is entered in an attempt to increase the Soft Limits beyond the values set at Initialization an "ERROR 1020 : Enter correct value" will occur (See Figure 3).

Figure 3: Error 1020 for increasing soft limits beyond initialization values

To increase the Soft Limits beyond the values set at Initialization it is necessary to modify the Soft Limit parameters using pulse values. For example, the MH12 Soft Limit values in pulse units can be viewed in the SOFTLIMIT SETTING screen (See Figure 4).

Figure 4: MH12 Soft Limits in Pulse Units

These values are also stored in S1C1G parameters 400 through 414 (See Figure 5).

Figure 5: MA1440 Soft Limit Parameters

The T-axis parameters S1C1G405 and S1C1G413 can be edited to have the same values as in the MH12 to allow for +-360 degree range of motion (See Figure 6). Main power to the DX200 controller must be cycled for these changes to take effect.

Figure 6: Modified MA1440 Soft Limit Parameters

Warnings

Any changes to Soft Limits should be verified to ensure that the manipulator and auxiliary equipment are able to move without causing undue strains or collisions.

If the Soft Limits are again reduced below the limits set by new parameters by using the SOFTLIMIT SETTING screens, the reduced values will overwrite the parameter values and become the new maximum Soft Limits.  Attempting to change back to the larger values using only the SOFTLIMIT SETTING screens will again result in "ERROR 1020 : Enter correct value."  If larger values are needed they must again be entered into the S1C1G parameters.