6.3 RS-485 command line mode (ASCII text retrieval)
When using the RS-485 interface, the default transmission protocol is the SDI-12 protocol. This assumes that the data recording
device connected can process the SDI-12 protocol. The OTT netDL or OTT DuoSens dataloggers can handle this protocol.
To easily incorporate the OTT Pluvio
2
S unit into any measuring station infrastructure, a so-called command line mode is
implemented in the OTT Pluvio
2
S. Using an ASCII character format command set, any measured values can be retrieved
and various settings made. This command set must be implemented in the data recording device. In the OTT Pluvio
2
S unit,
a number of operating parameters are to be set using the OTT Pluvio
2
operating software.
Switching to RS-485 command line mode
Communication interface: RS-485 or RS-485 4-wire
RS-485 protocol type: ASCII Text …
Transmission parameters
… 57 600; 19 200;
9 600
; 4 800; 2 400; 1 200 bd (8 N 1)
Units
Temperature values: °C · °F
Intensity: mm/min · mm/h
inch/min · inch/h
Commands
M[separator]<CR>
returns the measurements “Intensity RT”; “Accu RT/NRT;” “Accu NRT”;
“Accu total NRT”; “Bucket RT”; “Bucket NRT”; “Temperature load cell”;
“Heater status”, “Status”, as a sequence of ASCII characters.
After the character
M
, any separator can follow optionally. This character then sep-
arates the individual values from each other in the answer from the OTT Pluvio
2
S.
Refer to Chapter 6.1. for a description of measured value formats and status infor-
mation.
E[separator]<CR>
additionally to the command
M
returns the values “Temperature electronics unit”,
“Supply voltage” and “Temperature orifice ring rim”
request measured values optionally with CRC (Cyclic Redundancy Check)*. In this
case, the measured values output are extended by a CRC value.
RPT<CR>
repeats the last command executed; e.g. when CRC-check* is erroneous. In this case
the OTT Pluvio
2
S does not determine new measured values, but displays the
buffered measured values repeatedly.
R<CR>
resets the value “Accu total NRT” to zero
W<CR>
switches the orifice rim heater ON
S<CR>
switches the orifice rim heater OFF
I<CR>
retrieves various pieces of information from the device: Serial number, firmware,
device version, unit, hardware index, PCB number, load cell number
Examples
M;<CR> +0.000;+0.000;+0.000;+0.000;+269.280;
+269.281;+24.5;+255;+0<CR><LF>
MCRC;<CR> +0.000;+0.000;+0.000;+0.000;+269.277;
+269.281;+24.5;+255;+0CRC9EFA;<CR><LF>
E;<CR> +0.000;+0.000;+0.000;+0.000;+269.280;+269.281;
+24.5;+255;+0;+25.4;+12.1;+99.9CRCC8C8;<CR><LF>
R<CR> OK<CR><LF>
W<CR> Heating ON<CR><LF>
S<CR> Heating OFF<CR><LF>
I<CR> 361534;V1.03.0;200;mm/h;H1;800380210;31353651;<CR><LF>6
Note:
Each command
M
or
E
resets the total measured values
Accu RT-NRT
and
Accu NRT
to zero!
* cyclic redundancy check: method for determining a checksum in order to be able to detect errors during data transmission.
(Technical details: CRC-CCITT (CRC-16); CRC order: 16; CRC polynom: 1021; Initial value: 0; Final XOR value: 0
MCRC[separator]<CR>
ECRC[separator]<CR>
35
