Hirschmann MACH 4000 - Page 256

Diagnostics
256
9.7 Device Status
RM Web
Release 6.0 07/2010
Note: With a non-redundant voltage supply, the device reports the absence
of a supply voltage. If you do not want this message to be displayed, feed the
supply voltage over both inputs or switch off the monitoring (see on page 257
“Signal contact“).