Honeywell SV2 Series User Manual page 46

SV2 Series Safety Shut-off Valves
CHAPTER 3 : COMMUNICATION / CONNECTIVITY
Introduction
SV2 Series valve models with intelligence levels of 6 have embedded Modbus RTU communications. SV2 valves can
communicate via Modbus RTU open protocol with any compatible device. The SV2 Series valves and HMI / PC Tools support RS-
485 Modbus RTU communications with:
• 1 start bit
• 8 data bits
• 1 stop bit
• no parity
The SV2 Series valves can communicate with:
• The SV2 Series HMI programming tool directly
• The SV2 Series PC programming tool via a USB to RS-485 converter (included
in the PCTOOLKIT-000)
• An external Modbus master device such as a building automation system
directly
• An external Modbus master device via the HMI Tool second port with 'Gateway
– Connect to External Systems' selection. With this communication option,
the HMI Tool would likely be permanently installed.
The RS-485 interface between the valve and the externally connected device must be setup properly including wiring, bias and
termination resistor selection at valve, baud rate and Modbus addressing. Refer to the Valve Modbus Bias Setup section of this
document for more information as well as the reference documents listed at the end of this section for proper SV2 Series valve
and Programming Tools Modbus wiring and setup.
The HMI or PC Tools automatically communicate with the valve once properly connected. Either of these tools is required for
initial setup of any intelligent features. After initial valve setup is complete, the HMI or PC Tools may be left in place, removed
or replaced with a building automation system connection. If any of the Modbus master configurations shown above are used,
it can monitor and/or control the connected valve(s). Certain writable features may be dependent on the connected Modbus
master device. Note that the HMI and PC Tools have built-in monitoring, troubleshooting, diagnostics and trending capabilities
as well.
When connected to a building automation system Modbus master either directly or through a secondary port on the HMI
Tool, the Modbus master control must be programmed to recognize the various SV2 Series valve Modbus registers since
communication is not automatic. Refer to the Modbus Addressing section of this manual for the Modbus addressing
information.
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