Hi

I purchased a '94 VMC20 about 2 years ago with a CNC 88HS controller. I'm new to CNC and Fadal's but am technical and learn quick. I’ve been cleaning it up and slowly figuring it all out. I recently installed a Renishaw Optical Probe receiver (OMI) and MP10 probe. To really make this work correctly I wanted access to the I and J macro variables so I can hook up and read the Error and Batt Low lines as well as toggle the start code for the probe. (I and J macro variables allow you to set / get the state of some of the J12 pins on the 1040-2A mill interface card). I found out that the EPROMs in the CPU I had been running (1400-4 with 96.1 B4-3) apparently have a bug that returns an error when you try to use them in your code. (i.e. #V1=I(4) will return an error). I found a 1400-5A CPU on fleabay with 101.5 firmware. I swapped cards, zero’ed the memory and re-entered all the params from my old CPU. It seemingly boots and runs fine, as I’m able to run programs, etc.

Where the problem lies is in JOG. If I’m in any mode other than MDI - whenever I hit the jog key - it immediately jumps back out of jog. When in MDI, I can get it to jog pretty reliably. It’s worth noting this problem showed up BEFORE the CPU change, but it was much more random - i.e. it only happened sometimes and I could jog in the other modes maybe 7 out of 10 times. With the new CPU its much worse. limited JOG to MDI.

The fact that the problem existed prior to the CPU change, but is worse now made me believe it was probably some sort of adjustment that was “on the edge”. The newer CPU being more sensitive to the condition. I was thinking it would end up I would need to go through something like the Position Loop Gain or Master Feed Rate Clock procedures.

So to summarize:

Start in Command Mode
Press JOG
Notice Immediately jumps out
Press Manual 2x to get to MDI mode
Press JOG
No problem - stays in JOG.

The machine has a 4th axis card installed. I don’t use this axis (at least not yet…) and in SETP it’s set up as XYZ only. I assume this means the CPU will ignore this card. All the axis cards are 1010-4’s and they all have EPROM v90.8P.

Can ANYONE point me in a direction here? Anyone have this sort of problem?

Thanks in advance! -- David