Halma Alicat Scientific IVCD, Operating Manual

Page: 16 / 28

16 Setup
Setup
Sensor Setup
MENU → SETUP → Sensor
Choosing Engineering Units
SETUP → Sensor → Engineering Units
Changing engineering units alters both the display and the data frame. Choose the parameter whose unit you want to
change, and then choose an engineering unit. Confirm the change on the last screen.
Pressure Averaging
SETUP → Sensor → Pressure Averaging
Averaging the pressure over a longer time may be useful in smoothing fluctuating readings. This menu changes the time
constant of the geometric running average for pressure. Values roughly correspond to the time constant (in milliseconds)
of the averaged values. Higher numbers generate a greater smoothing effect, to a maximum of 255 ms.
Zero Band
SETUP → Sensor → Zero Band
The zero band threshold is an amount of pressure under which pressure values are displayed as 0. The maximum zero
band is 6.38%. This function also applies to gauge pressure readings when using the optional barometer. For example,
a 20 PSIG controller with a zero band value of 0.25% would display all readings between -0.05 and 0.05 PSIG as 0 PSIG.
Configuring Serial Communications
MENU → SETUP → RS-232 Serial or RS-485 Serial
You can operate the pressure controller remotely via its data connection for easy streaming and logging of all data.
Before connecting the pressure controller to a computer, ensure that it is ready to communicate with your computer by
checking the options in this menu.
For more on how to issue commands from a computer, see
page 18 .
Unit ID
SETUP → RS-232 Serial or RS-485 Serial → Unit ID
The unit ID is the identifier that a computer uses to distinguish your device from other, similar devices when connected
to a network. Using the unit ID letters A–Z, you can connect up to 26 devices to a computer at the same time via a single
COM port. This is called polling mode ( page 18 ). Unit ID changes take effect when you select SET.
If you select “
@
” as the Unit ID, the pressure controller will enter streaming mode when you exit the menu ( page 19 ).
Modbus RTU Configuration
SETUP → RS-232 Serial or RS-485 Serial → Modbus Address
SETUP → RS-232 Serial or RS-485 Serial → Modbus
Modbus Address
The Modbus address is the identifier that a computer or programmable logic computer (PLC) uses to distinguish your
device from other devices when connected to a Modbus network. Values of 1–247 are available for use.
Managing Setpoint with an Idle Modbus Connection
If a Modbus connection is idle for a specified amount of time, the device can be configured to set a zero setpoint, or
maintain the previous setpoint. The idle time will be infinite by default and can be set, in seconds, up to 99999.9 seconds
(1 day, 3 hours, 46 minutes, 39.9 seconds).
The setup menu .