Delta Controls DZNR-768 Installation Manual page 13

Make sure to ground the DZNR using the ground lug that is available on
the DZNR. The DZNR uses the ground lug to establish a common reference
for communications. If the DZNR is not grounded then communication
problems may occur.
Select an external power supply that is certified for safety for the correct
destination country and that has an output rating, which is considered an
NEC Class 2 or Limited Power Source with the rating not to exceed 30 V
rms, 42.4 V peak, 100 VA.
Be sure that the transformer polarity is consistent across all controllers
sharing a common transformer.
Refer to the Delta Controls Wiring and Installation Guidelines document
for additional information and wiring options.
DZNR-768 Revision 1.2 Installation Guide
Document Edition 1.5
Page 13 of 28