VEICHI VH Left Expansion Boards
Extra isolated RS485 and a real-time clock
A single board on the left-hand side of a VH controller, adding two isolated RS485 channels and optionally a battery-backed real-time clock. The usual reason to fit one is a second Modbus network, or timestamped logging that has to survive a power cut.
- Board types
- VH-RS485, VH-RS485-RTC, VH-RTC
- Interfaces
- Dual isolated RS485; I2C on RTC variants
- Slaves
- Up to 31 (50 on VH600)
- Baud rates
- 9.6 / 19.2 / 38.4 / 57.6 / 115.2 kbit/s
- Distance
- Under 100 m at full speed; under 1,000 m at 19.2 kbit/s
- RTC battery
- CR2354 coin cell, 5-year rated life
One board fits VH300, VH500 and VH600
Dip-switch selectable termination resistor
Real-time clock accurate to within 120 seconds a month
Replaceable long-life battery
Typical applications
Adding a second Modbus RS485 networkTimestamped data logging and batch recordsLong-distance serial links to remote panels