Quote Originally Posted by Robin Hewitt View Post
I hear what you say about measuring volts rather than resistance, sounds very logical.

The hydraulic interruptor looks like an afterthought because it doesn't wire to the little distribution board which does the rest of the guard switches. According to the hydraulic circuit diagram it diverts any oil sent to the platen closing ram straight back to the reservoir. I presume they used the electrical switch on it simply because it was there. It seems to do exactly the same job as the "read-contactor".

After much reeding of the manual, I have found a reference to an optional, "pneumatic safety gate" which I don't have. I believe it locks the guards shut while the machine cycles but the manual is vague. There is a socket where an "auxiliary control box" plugs in and the manual says, "Jumper plug in b41/b42 if control box is not connected. Without plug in b41/b42: no mould closing". Off the top of my head, I can't remember there being a plug in it, this could be fun to try and recreate without a circuit diagram if it isn't there. OTOH it would be nice to think that wiring and sensors are all present and correct.
Mr. Hewitt,
Through a search for a problem (almost exactly what you describe) I found your posts on MYCNCUK...
I have just obtained an Arburg very similar to yours (221-75-350) with what appears to be the same problem. I cannot get the moving platen to move forward. It will move back (if I adjust the stops b44 etc.), but it seems to me that the hydraulic interruptor is not allowing the platen to move forward. I traced my connections, and I have the b20 lit (safety gate switches). I am able to move the ejectors forward and back, but when I press the mold close button, I hear the machine trying to deliver pressure, but no movement. Any suggestions you have would greatly be appreciated.