Price PCV Series Manual page 26

PRESSURE CONTROL VALVE
MAINTENANCE
Troubleshooting - Continued
Fault
BACnet Communication Errors
BACnet Communication Errors
BACnet Communication Errors
BACnet Communication Errors
24 PRESSURE CONTROL VALVE - Manual | priceindustries.com
Solution
BACnet MS/TP networks must be terminated to ensure proper operation. A network should
be terminated twice, once at the beginning and once at the end. Termination helps reduce
reflections and noise. The terminating can be done with a 100 ohm resistor across the A+
and B- lines, but most Price controllers have the option for enabling termination by flipping
DIP switch #8 to the ON position.The network speed or baud rate must be the same
throughout the network.
NOTE: The default speed for Price BACnet MS/TP controls is 76800. BACnet MS/TP
currently supports 4 standard speeds which are: 9600, 19200, 38400 and 76800.
Binary Address must be unique for each device on the network. No two devices can have
the same Address. This includes if you are incorporating a Price product into an existing
network. Determine the existing binary Addressing scheme for the existing network. The
Address is set on the Addressable DIP switches on the PIC.
Grounding and 24VAC polarity: Proper grounding is absolutely essential when wiring the
MS/TP BACnet Network. Proper grounding will prevent many potential problems that can
occur in a network of devices. Common symptoms of a poorly grounded network can
include inconsistent BACnet MS/TP communications and damage from voltage spikes. The
most practical method of grounding is to ground every 24VAC transformer common/neutral
used to power the controls.
Connect the "common/neutral" wire of the SECONDARY side of the transformer to earth
ground – such as the ground screw on in the electrical box.
NOTE: Flipping 24VAC HOT and COMMON will cause the BACnet MS/TP Network to stop
communicating!!! Ensure HOT and COMMON are not reversed on ANY controllers.
WARNING: Controllers will still power up and run even if HOT and COMMON are reversed.
However output signals to other devices such as heaters, relays, etc will not work as
intended!
24 VAC Hot
High Voltage Primary
Side
24 VAC Common