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Our mechanical guys told me they will want to keep the external load cell after all. This is part of a Kistler force vs. distance monitoring system that can record a curve with evaluation objects to give a pass/fail to the PLC. We can also use this to record the maximum force and the distance that this occurred at for traceability purposes. We are using this operation to seat a PCB into a plastic housing so torque/force overshoot and over straining the part is big issue. The requirements are then to have a system that can stop as quickly is possible. Since we will still have the external load cell with the Kistler system, we can use this to correlate the load to the torque of the servo motor. I guess we can use this then to set the torque value for the MC_TorqueControl instruction. I guess this would be ok? And the force vs. motor torque curve is linear? I have been reading the manual and I think maybe this is one possible way to do the press operation. Step 1: Move Absolute (MC_MoveAbsolute) Use this to move the axis down from the home/start position at a fast speed to the pressing start position Buffer mode is set to ‘Blending Next’ Step 2: Move Velocity (MC_MoveVelocity) Use this as the intermediate step to slow down the axis to a slower speed for the pressing operation Buffer mode is set to ‘Blending Next’ Switch to next instruction once ‘InVelocity’ is on Step 3: Torque Control (MC_TorqueControl) The ‘Torque’ input comes from the product setting depending on product type. Step 4: MC_Stop Stop the axis motion once the ‘InTorque’ variable turns on Step 5: Move Absolute Retract the axis to the safe position I attached a graph that I found online for what I am trying to do. 2021-10-21_16-30-57.bmp

I am not using the Beckhoff junction box currently. I was just looking for an alternative because Omron is terribly backlogged with their stock.

The problem with the part is once it seats, the force spikes up almost vertically. This is why it's bad for strain and we want to stop the axis as fast as possible.

We are trying to control the torque. Once we see the torque exceed what is needed to seat the part then we retract the axis. The problem we had before was applying too much strain on the part by over-pressing. The axis needed some time before it comes to a stop. We were able to minimize this by moving the axis really slowly during the last 3mm or so but of course everyone wants faster cycle times now. That's why we have to figure out how to do this faster.

I want to use a 1S servo drive and motor for a pressing operation. The intention is for the motor to drive downwards until it sees a preset torque value (1 kN). Is this possible with the 1S servo drive and motor?  I know the servo drive has a MC_MoveFeed instruction which we have been using with an external load cell input. The load cell sends a hardwired input to the drive to stop when it sees enough loading on the part. The problem with this has always been overshoot so we have to drive downwards very slowly. The question now is if we can forgo the external load cell and do everything internally with the drive and motor and get a better response for stopping.  I want to find out if it’s possible for me to do it this way:  Use a MC_MoveAbsolute instruction to move the axis to a start position Setup the buffer mode for the move absolute instruction to blending next. I think this will continue the axis movement without stopping the axis. The next instruction will be MC_TorqueControl The axis continues until it gets to the preset torque value Use the MC_Stop instruction to stop the execution of the MC_TorqueControl instruction Use a MC_MoveAbsolute instruction to retract the axis to the home position   Will this setup work?  

I found it on the Omron site. There's a video. Only available for Sysmac versions 1.45 onwards. https://automation.omron.com/en/ca/video/player/17891

Can you show me where to find this create EDS tool for Sysmac? I can't find it anywhere with my Sysmac.  Thanks.

It looks like this is RunTime dependent for the HMI. I looked for this with an older project running RunTime 1.11 and it didn't have this function. A newer project using RunTime 1.15 has this function. It's a nice feature to have for sure.

I did some more research and I see TwinCAT has a XAE version for development and a XAR version for deploying to PCs in the field. XAR only has the runtime for machine control and XAE has a user interface for connecting to the device with the XAR. 

I am still not quite sure how to go about programming each 'PLC' in TwinCAT. I am used to having programming software on my laptop and then going 'online' with each PLC in the field. The programming software travels with me. Beckhoff is different because each controller is a PC. So does the programming software stay resident on the PLC in the field? Meaning you need a TwinCAT license per PLC in the field? Then all you need then is a monitor, mouse, and keyboard to program each PLC (and I don't have to bring my laptop along)? I guess I would still need TwinCAT on my laptop to do offline programming. In this case does TwinCAT take over one of my CPU cores and make a virtual PLC? 

I remember trying to learn and use TwinCAT 2 about 12 years ago. At the time I had it installed on my laptop and it kind of messed it up. Is it better to buy a small Beckhoff IPC to try to learn TwinCAT? 

@photovoltaic: You are right about the WriteDat variable datatype. I changed this to DINT to match the range of the 4020 object. The instruction works now and I can freely write to 4020.01. Thanks for the help. I guess the lesson here is the datatype must match whatever you are trying to write to. 2021-09-30_11-06-05.bmp

I just changed the value of 4020.01 to 128. The drive took the change after cycling power. Now the brake interlock warning is masked and there are no more drive warnings. I still don't understand what the problem is doing it the long way using the EC_CoESDOWrite instruction. Something is invalid but I am not sure what. 2021-09-30_9-17-10.bmp

So I should be able to change this value here to 128? The I can transfer this selection to the drive? The attribute for this parameter is 'R'. Does this mean the value will reset to '0' when the servo drive is power cycled? 2021-09-29_13-08-34.bmp

From what I am reading in the manual, setting bit 7 for Subindex 5 will turn this brake interlock warning into an error. Right now this brake interlock warning just appears as an observation. Despite of it being just an observation, it still shows up as a drive warning. 2021-09-29_13-10-08.bmp