Technical Papers

In April 2011 a minor change was made to DeadEasy 31 HMI PCB and DIN rail mount electronics PCB to provide better self test performance.  The current version is Minor Revision 3.  Normally the self test transmit signal path is from the transmitter through the lens cap, bounce off an operator’s hand, return through the lens cap and into the receiver which initiates a self test. We found that in the HMI Minor Revision 2, a portion of the self test transmit signal was passing through the HMI PCB and into the underside of the self test signal receiver.  This issue came out of left field as manufacturer’s data suggests only the top face of the receiver will receive signal.  The modification involved inserting a copper layer on the HMI PCB to block the bypassed transmit signal.  This had the effect of reducing the ambient noise level and allowed us to reduce the self test transmit signal threshold on the DIN rail mount electronics PCB.

Users of DeadEasy 31 Minor Revision 2 should not be concerned as the “better self test performance” allows us to identify construction issues better at the time of pre-dispatch testing.  The “better self test performance” is imperceptible to an operator.  Future purchases will be of Revision 3 units.

Changes to the HMI PCB and DIN rail mount electronics PCB, however means that DeadEasy 31 Minor Revision 3 HMI and DIN mounted electronics are not interchangeable with Revision 2 components.  The first DeadEasy 31 Minor Revision 3 versions carried the serial number #21D.  Serial numbers are hexadecimal.

In general, we suggest that HMI PCB and DIN rail mount electronics PCB carrying the same serial numbers be kept together in the installation as they are both from the same construction batch.