Chapter 3 ________________________________________________________________ Installation
VAISALA ________________________________________________________________________ 25
NOTE
There is a hysteresis around the setpoint value to prevent rapid relay
switching when the measured value moves around the setpoint. This
means that the relay will not close or open exactly at the setpoint, but
slightly above and below.
-
On HMW93 the hysteresis is 2 %RH in both directions.
-
On TMW93 the hysteresis is 1 °C (1.8 °F) in both directions.
Configuration of Digital Output Models
Digital output models of the HMW90 series have the following
configuration interfaces:
- DIP switches on the component board control operating protocol,
serial line settings, and transmitter MAC address. For instructions, see
DIP Switches of Digital Output Models on page 26.
- You can set a jumper for RS-485 line termination on the component
board (120
Ω
resistor). For location of the jumper, see Figure 5 on
- Other settings are configured in software. You can change most
configuration settings through the service port. For connection
instructions and serial line commands, see Chapter 4, Operation, on
page 35.
- Some configuration actions can be done using the BACnet and
Modbus protocols. See the following appendices for protocol
implementation details:
- Appendix A, BACnet Reference, on page 87.
- Appendix B, Modbus Reference, on page 103.
