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PM101x
3.2.8 UART Operation
The PM101 is delivered in RS232 operation but can be switched to UART operation.
UART dependent PM101 functions:
The PM101 may need to be switched from RS232 to UART operation when using an external
micro controller for PM101 control. In RS232 operation the PM101 uses voltage levels of +/-5
V, while in UART mode the voltage level is shifted to 0/5 V. The PM101 can also be adjusted to
accommodate micro-controllers using 3.3 V. When switched to 3.3 V, UART operation is toler-
ant for 5 V input signal.
For instructions on how to change the voltage level for UART operation, please refer to the doc-
ument Write-Your-Own-Applications (WYOA) for PM101x.
For UART operation, please use standard protocols for UART communication and the SCPI
commands listed in WYOA for PM101x.
3.2.9 Reset Button
This button reboots the internal micro controller of the PM101x. To press the button, please use
a small device that will not break inside the instrument. All settings are saved due to the in-
ternal non-volatile memory.
3.2.10 Baud Rate
For PM101 and PM101R, the Baud rate can be adjusted from 9600 to 230400 Bit/s. This can
be done either via the USB interface or via the serial interface using SCPI commands or driver
functions. Please see the document Write-Your-Own-Applications (WYOA) for PM101x. The
default baud Rate is 115200.
Note
After adjusting the Baud Rate via RS232 or UART, close the RS232 or UART connection and
reconnect with the desired Baud Rate in order for the Baud Rate to communicate it via
RS232/UART. This is not required for operation via USB.
3.2.11 Non-Volatile Memory
All PM101x models have an internal non-volatile memory for all settings (i.e. wavelength set-
ting, ranging, analog output configuration). The PM101x will start in the same configuration as
prior to shut-down.
3.2.12 Auxiliary I/O Ports
PM101 with its DA-15 connector gives access to two configurable general purpose input/output
(I/O) Pins (DA-15 Pins 2 and 3). Please see the
in the appendix. These aux-
iliary I/O ports use 3 V logic for output and are tolerant for 5 V input signal.
The I/O port can be controlled or monitored via the instrument driver or through SCPI com-
mands in custom made software.
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