Fluke 45 user manual Typical IEEE-488 Input Strings, Sending Numeric Values to the Meter

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Users Manual

Enable Register" later in Chapter 5) and the input string is discarded. If, on the other hand, the input buffer becomes full when the IEEE-488 interface is used, the meter stops accepting characters until there is room in the buffer. Characters in the input buffer cannot be over-written with the IEEE-488 interface.

Valid terminators for the RS-232 interface are:

•LF (Line Feed)

•CR (Carriage Return)

•CR LF (Carriage Return/ Line Feed)

Valid terminators for the IEEE-488 interface are:

•EOI (End or Identity) on any character

•LF (Line Feed)

In some instances, a terminator is automatically transmitted at the end of the host’s output string (i.e., the meter’s input string). For example, in Fluke BASIC, the PRINT statement finishes with a CR LF pair.

Typical IEEE-488 Input Strings

Two typical strings that could be sent to the meter over the IEEE-488 interface are shown in Figure 5-1. These strings are written in Fluke BASIC to be sent from a Fluke 1722A Instrument Controller.

Sending Numeric Values to the Meter

Numeric values can be sent to the meter as integers, real numbers, or real numbers with exponents as shown in the following examples:

EXAMPLE	EXPLANATION
+12345689	Sends the signed integer "+12345689"
-1.2345E2	Sends-1.2345 x 102

Sending Command Strings to the Meter

Observe the following rules when you construct strings to be sent to the meter over the computer interface:

•RULE 1: READ METER’S OUTPUT BUFFER ONLY ONCE FOR EACH QUERY COMMAND.

The meters output buffer is cleared after it has been read. This prevents previously read data from being read a second time by mistake. If you attempt to read the meters output buffer twice without an intervening query, the meter will not respond to the second read.

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