Tip of the Day 104: Bypassing Inject Enable in Manual Mode

 

There are strange things done in manual mode

By those who presses wrangle;

Or so I’m told by molders bold

Who use Inject Enable.

 

They purge, retract or build a shot

Or even pull the barrel

While the eDART, sleeping or just awake,

Makes trouble sure to rankle.

 

(apologies to Robert Service)

 

As noted in tip # 96 the Control Output / Inject Enable provides value by preventing damage in case a controlling sensor fails or becomes disconnected. But I have heard that this can be quite frustrating to those trying to maintain the machine or operate it when there is no real job or mold there. In fact the eDART™ may be turned off or just powered on and the Inject Enable output is not even defined yet. So the relay contact remains open.

A press with a programmable controller could be programmed to ignore that input when in manual mode. But often presses are not programmable or it is very expensive to change a program. So customers sometimes wire the Inject Enable output in series with the purge guard switch or some other safety circuit. With the eDART off they can do nothing, even with the press in Manual mode.

Here is a suggested circuit to bypass the Inject Enable when in manual mode. A relay is driven by the signal from the controller that is on while in manual (also fed into the eDART’s Sequence Module, or ID-7). When in manual the relay closes a contact that goes around the Inject Enable circuit. This lets the operator do whatever is necessary in manual mode.

If your machine puts out a „Machine in Auto/Semi“ signal instead of manual then you can use the same wiring scheme except that CR1 would need to have SPDT contacts and you would wire the bypass across the normally closed contacts (  ).