I'll start at the beginning. I have a Citizen Cincom E32 dual spindle lathe. I started getting an EX118 Alarm which is a Back(Sub) spindle RPM error. This alarm occurs if the controller sees a parameter set difference of 10% rpm of the spindle to the set point. The speed displayed that is set, is only ever off by about 1-2 rpms when the alarm occurs. Never any alarms on the drive itself. I searched through the ladder and found the alarm bit connected to basically 2 normally open input contacts addressed as U008C and U008D, labeled as Upper or lower limit exceeded. These according to meldas programming manual are device inputs. I tried increasing the parameter to 50% and still getting the error. The system is a Meldas controller using a MC652 servo interface card to connect the servo amplifiers.

Here is a crude drawing of the connections:
Attachment 275106

My question is, Does anyone know this system well enough to tell me where this U8D signal is coming from? I found the pin out of the CAM11 cable that is linking all of the drives together but there is nothing specifying this signal specifically. Is it a internal bit being fired by the MC652 card or is it coming from the MR-S amplifier itself? If clarification needed on anything please ask away. Stuck on this one. Not sure if i should just replace the MC652 card or the amplifier and even if either of these are the cause of the problem.
Attached is also the pinout for the CAM1 connector for the interface to the amplifiers. I would have to assume this is a serial interface and not a discrete io?

Any help is appreciated. Thanks in advance.