User manual

GOSSEN-METRAWATT 25

Each message, regardless of being a command or a reply, has the following structure:

<OPERATION><ADRESSE><OPERATOR>[PARAMETER[;PARAMETER]] <DELIMITER$>

<OPERATION> This is the proper command, e.g. IDN? gives the equipment identification.

<ADRESSE> The SECUTEST PSI knows the address states "Not addressed" and "Address

assigned" (with IDN).

Instructions without addressing: (general instructions)

The SECUTEST PSI always reacts (e.g. to read the actual address with IDN?).

Instructions with addressing: In a non-addressed state, the SECUTEST PSI does not always react,

in an addressed state only when the sent address agrees with the actual address.

<OPERATOR> Shows whether it is

a request ... ?

an assignment... ! or

a response ...=

<PARAMETER> Four basic types are distinguished:

– TYPE1: Fixed parameters, e.g. "ON", "OFF", "M" ...

They must exactly be written as specified.

– TYPE2: Variable parameters, e.g. "GTM5015-S series 12345"

Random character strings can be transmitted here.

– TYPE3: Numeric parameters, e.g. "<-121.0" or "0539" are transmitted with a floating

point and may be up to 7 characters long.

They must always be separated by the delimiter ";".

– TYPE4: Measuring number (consisting of type of measurement and measuring range)

<DELIMITER$>:As delimiter, the '$' character marks the end of a message.

It is always followed by the checksum

<CHKSUM> The checksum is always relative to the total previous message including the

$ delimiter. It is transmitted with 2 ASCII characters.

<CR> The carriage return (chr$(13)) character concludes a message. With the recognition

of <CR>, the SECUTEST PSI tester accepts a message from the input buffer to the

working buffer and then performs a syntax test. If this is successful, a reply mes-

sage is sent.