Tip of the Day 116: Pack to Hold Transfer Ignores Sequence

Some recent questions made me realize that not everyone understands how the eDART™’s Pack to Hold Transfer tool works.

A customer wanted to do cavity pressure control with an eDART™. He could not get the sequence signals from the machine (I think Injection Forward). He and our support person were concerned that they could not do cavity pressure control without the sequence signals. So, the point is…

You can do reliable cavity pressure control on an eDART without having “hard” sequence signals from the machine.

Of course without the signals you will be missing some analytical information, will need to set the volume zero manually and may need to adjust Sequence Setting thresholds to get good data. But the V->P transfer will work with or without wired sequence signals.

The title of this tip says most of it. Since mistakes in sequence wiring are not uncommon we decided long ago that the signal to transfer the machine on cavity pressure should operate regardless of the sequence inputs. This way the signal to transfer at a certain cavity pressure always goes out to the machine even if the eDART sequence signals are wired or named wrong.

Key Point: This ignorance of sequence signals applies only to the cavity pressure setpoint in the V->P transfer tool. The backup values and temperature transfer values DO require proper sequence signals in order to work correctly.

Here is an example in which someone named the screw run signal from the machine “Injection Forward” by mistake.

Of course the eDART needs to know when to turn the Control Output / V->P Xfer. off. It can use 95 % of the setpoint or the end of Machine Sequence / Injection Forward. This is set in the “Settings” menu on the V to P Transfer tool. This graph shows the proper injection forward signal with the V->P off point set to end of injection.

As you may notice from the above V->P tool actually does examine at least one sequence signal if you choose to set it up that way. But, if you tell it to turn the V->P output off at the end of injection it will leave it on if it finds that the cavity pressure is still above the setpoint.

Here is an example with a high pressure at the end of injection.

The “point” comes from a problem. A customer wanted to do cavity pressure control with an eDART™. He could not get the sequence signals from the machine (I think Injection Forward). He and our support person were concerned that they could not do cavity pressure control without the sequence signals. So, the point is…

You can do reliable cavity pressure control on an eDART without having “hard” sequence signals from the machine.

Of course without the signals you will be missing some analytical information, will need to set the volume zero manually and may need to adjust Sequence Setting thresholds to get good data. But the V->P transfer will work with or without wired sequence signals.