User guide

set switches
Chapter 2 Command Descriptions 211
txcontrol={alwayson|auto}
Specifies how the 422/485 drivers should be connected to the lines. As
the drivers support Tri-state mode, this option can be set so that
transmitter is always on, or actively driving the line, or only on if data is to
be transmitted.
This option is only valid for four-wire configurations; that is, if the "wires"
option is set to "four." In two-wire configurations, the PortServer TS MEI
always uses "auto."
alwayson
The transmitter is always actively driving the line. Set this option to
"alwayson" if this device is the only one transmitting on a one-wire pair,
such as a single master in a master-slave configuration, or if only two
devices are attached.
auto
The transmitter is only active when data is sent; otherwise, it is
switched to high-impedance mode. Set this option to "auto" if multiple
devices need to share the bus in a dual master scenario or if the device
is acting as slave in a multidrop environment.
The default for four-wire settings is "alwayson."
wires={two|four}
Applies when the serial port is running in 485 mode only. Specifies the
manner in which the transmit and receive wires are connected.
two
The serial port operates in two-wire mode. This value implies that the
"txcontrol" option is set to "auto" at all times.
four
The serial port operates in four-wire mode.
The default is "four." For a detailed description of the pinouts for an
asynchronous port, see the alternate 8-pin settings for the "pinout"
option.
termination={on|off}
Applies when the serial port is running in 485 mode only. Determines
whether termination resistance is enabled across the lines.
on
Termination resistance is enabled across the lines.
off
Termination resistance is disabled across the lines.
The default is "off."
enable={on|off}
Enables or disables a serial port’s transmitter.
on
Enables a serial port’s transmitter.
off
Disables a serial port’s transmitter.
The default is "on."