4.3 The 'set' Command

To set the operational parameters the power sensor, request the 'set' document with a HTTP GET command and append the parameters which shall be set to the URL. The path which must be sent with the GET request is

/set?fmt=txt&...

where ... stands for an arbitrary number of parameter definitions, each consisting of a key word and the associated parameter value, separated by a '=' character. Assuming the power sensor listens to the IP address 10.0.0.1, an example URL for this request is:

http://10.0.0.1/set?fmt=txt&smod=AUTO&offs=0

The 'fmt=txt' parameter forces the power sensor to reply a one line text document rather than the HTML coded page which is normally displayed by the web browser. The parameter definitions 'smod=AUTO' and 'offs=0' shown in the above example make the power sensor to select it's sensivity range automatically and to clear any user defined offset to the measurement value. For a complete list of keywords see the table below.

The power sensor replies to every 'set' request with a complete list of parameters in one line. Like with the 'read' command, the line consists of a set of keyword - value pairs, separated by '&' characters. Within each pair, keyword and value are separated by the '=' character.

smod=AUTO&fltr=OFF&thrh=-99.99&freq=0&fcor=0.00&offs=0.00&snr=0D8F9

The values contained in this list are the values which actually are applying, including the new values read from the 'set' URL. The power sensor does not give a fault message if it receives an invalid parameter definition. It limits parameter values to a valid range or selections instead. If a keyword is not known, it ignores this parameter completely. To read the parameters actually set with changing a value, send a HTTP GET request with 'fmt=txt' as the only parameter.

The table below describes the valid parameter settings (keywords and selection tokens are case sensitive):

• smod --- Sets the sensivity range, the power sensor uses. AUTO makes the power sensor select the appropriate range automatically. LOW selects the low sensivity range (for high levels), HIGH selects the high sensivity range. It is strongly recommended to operate the power sensor with smod=AUTO . The power sensor uses this as fall-back, if it receives an invalid 'smod' selection.
• fltr --- Sets the filter, the power sensor applies to the measured values. Valid choices are OFF , FAST and SLOW . OFF is the default value the power sensor uses if it recognizes an invalid 'fltr' selection.
• thrh --- Defines the alarm threshold value. If the displayed power value (with any user defines offset and frequency response calibration already applied) drops below this limit, the power sensor reports a 'low signal' alarm and opens the fault relay contact. To disable the threshold, set it to -99.99.
• freq --- Defines the frequency of the measured signal in MHz. If this parameter is not zero, the power sensor looks up the frequency response calibration offset for the given frequency and adds this offset to each measured value before it is displayed. 'freq' accepts integer numbers on the range 0 .. 19000.
• fcor --- The calibration offset, the power sensor actually adds to each measured value due to the frequency response calibration. This value is zero unless you set a measurement frequency with the 'freq' parameter. The 'fcor' parameter is read-only, the value only can be set by changing the 'freq' parameter.
• offs --- The value [dB] specified with this parameter is added to the measured power before it is displayed and compared to the fault threshold value. If 'offs' is set to zero, the power sensor shows the power which is measured at it's input connector. The valid range for 'offs' is -99.99 to 99.99.
• snr --- The power sensor's serial number. This is a five digit hexadecimal number which uniquely identifies each individual unit. 'snr' is a read-only parameter.

Floating point numbers (as for the 'thrh' and 'offs' parameters) may consist of digits, one optional decimal point and a leading minus sign for negative numbers. The 'freq' parameter is restricted to be a positive integer, it may consist of digits only. Malformed numbers are recognized as zero.