Chapter 5 Remote Interface Reference

Scanning Overview

Scan Memory Commands

You can store up to 50,000 readings in non-volatile memory during a scan. Readings are stored only during a scan and all readings are automatically time stamped. If memory overflows (the MEM annunciator will turn on), a status register bit is set and new readings will overwrite the first readings stored (the most recent readings are always preserved). You can read the contents of memory at any time, even during a scan.

Reading memory

cleared when you read it.

Each reading is stored with measurement units, time stamp, channel number, and alarm status information. You can specify which information you want returned with the readings using the FORMat:READing commands. The following is an example of a reading stored in memory with all fields enabled (relative time is shown).

5

1 Reading with Units (26.195 °C)

3 Channel Number

2 Time Since Start of Scan (17 ms)

4 Alarm Limit Threshold Crossed

 

(0 = No Alarm, 1 = LO, 2 = HI)

DATA:POINts?

Count the total number of readings (from all channels in the scan list) currently stored in reading memory from a scan. Returns a value between 0 and 50,000 readings.

DATA:REMove? <t” >

Read and erase the specified number of readings from non-volatile memory. The readings are erased from memory starting with the oldest reading first. The purpose of this command is to allow you to periodically remove readings from memory during a scan than would normally cause reading memory to overflow (for example, during a scan with an infinite scan count). The output from this command is affected by the FORM:READ commands (see “Reading Format Commands” on page 231).

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HP 34970A manual Scanning Overview Scan Memory Commands, DATAPOINts?, DATAREMove? t