Setting Medar Stepper Conditions on Yaskawa Pendant

Subject: Medar Stepper Conditions
Controller: YRC1000
Product: MedWeld Pendant App for WTC MFDC Spot Timer
Application: Spot Welding
Robot: SP and GP
Security Level: Management

Summary: The Stepper Function is on the Medweld timer and boosts the current level based on the
number of spot welds. It is meant to compensate for the increased contact area (decrease in
resistance) as tips wear and mushroom. It is a programmable feature in the timer that has to be
determined for each application based on gun configuration, welding parameters, and quality level
desired. The number of spot welds is tracked by the timer. There is IO between the robot and timer
to notify when step maximum is being approached (to signify a tip dress cycle is warranted). The
robot can also reset the stepper after tip dress or tip change.

Sequence of Operation:

Programming: The Medar timer can be programmed by the Medar hand held programming pendant,
WTC PC Software, or the Yaskawa Pendant App on the teach pendant. Following are steps to modify
Stepper information using the MedWeld pendant application. Multiple timers can be accessed by
using the pull down menu for IP address and selecting the desired timer number to display.

The HOME screen of the MedWeld pendant application will display weld results for the last weld. It includes information on the Stepper file #, Step number, and Weld Count. More detailed information on a Stepper File can be displayed with Stepper Status display. It also has soft keys to manipulate the Stepper Count status. These can also be activated by robot outputs.

A default weld schedule will have the Stepper File # set to 0 which will not use a Stepper to boost current. However, each weld schedule has the potential to use a different Stepper File #. Generally, the same Stepper File # would be used for the same Gun. Different weld schedules used with that gun should reference the same Stepper File #. If there are multiple guns on the system, they would use different Stepper File#s.

The Stepper File can be modified from the Stepper Edit tab. The STEPs are defined by the number of spots to get to that Step and the % or amount of current boost to be applied to each weld after the Step. The Linear Stepper # (Function 82) must be set in the schedule to advance the stepper weld count. Be sure to use the desired Stepper # in each Schedule (the default must be changed from #0 to activate the Stepper).

To edit data in the screen, highlight the particular setting by touching it and key in the desired setting using the pendant numeric pad. DO NOT hit the enter key on the pendant (it will cause an error when Saving). DO touch the Apply key on the screen and it will update the line in the displayed program. When changes are made in the displayed schedule; you must hit SAVE to write it to the Medar.
The robot will respond with an Alarm when the timer has a FAULT condition. Many of the conditions that generate FAULTs can be changed to ALERTs. An ALERT will be logged in the timer and can be displayed in the STATUS screens, but it will not stop the robot. The ALERT/FAULT conditions can be changed in the SET-UP edit screen.

Inputs/Outputs: Yaskawa has set-up the Ethernet IO with particular functions in the timer. These IO will start at different locations based on your system, but will generally start at IN/OUT #33 or #3001. Additional signals can be defined in the timer by using the WTC pendant to modify EIP Settings and changing the Input or Output signal to the robot. This might include a Stepper Advance from the robot or other signals.