Manual - 8500A Series Peak Power Meter - Giga-tronics

Series 8500A Peak Power Meters
Temperature Difference Output Mode
This mode determines the difference in temperature for each detector since it was last calibrated. The
mode provides a means to maintain measurement accuracy by allowing the software to determine when a
detector Self-Cal is required. If detector temperature difference information is desired, the command
DTMP is sent to the PPM. The instrument will then be ready to output a data string in the following
format (x and y = temperature reading digits; s = polarity):
DTPAsxx.x,DTPBsyy.y(CR)(LF-EOI)
This will be true with both the Model 8501A and 8502A instruments. If a detector is not present, the
digit portion of the string will read +00.0. The zeros can either mean no change in temperature difference
or no detector present. With the 8501A, the B reading will always be zeros.
Sample Program:
Status Byte
10 ! THIS PROGRAM EXTRACTS
20 ! TEMPERATURE INFORMATION
30 ! FROM THE PPM SO THAT A
40 ! CONTROLLER CAN DETERMINE
50 ! IF A SELF-CAL IS REQUIRED.
60 ! IF THE TEMP SINCE LAST SELF-
70 ! CAL IS MORE THAN +/-5 DEG-C,
80 ! SELF-CAL IS RECOMMENDED
90 DIM A$(19)
100
110
120 OUTPUT 704;DTMP
130 ENTER 704;A$
140 DISP A$
150 END
The PPM uses this mode to send its status byte as a character string. The value sent is the internal status
value. It is not exactly the same as the byte sent during a serial poll in which bit-7 is high when service
is being requested (see Service Requests in Section 3.4). The character string sent out to represent the
status value will consist of a four character head, STAT, followed by three digits. This output mode can
only be active when SRQ is disabled. Service request status bytes are not buffered when SRQ is disabled,
so only the most recent status value will be output. The status value is followed by a carriage return,
followed by a line feed sent with EOI.
Stand Alone Plot Output Mode
Plotting Without Using a Controller:
The PPM uses this mode to send HPGL digital plotter commands to plot a pulse, much as it does in the
Plot Mode. The difference is that stand alone plots are initiated by commands from the front panel of the
PPM. This is to allow plotting without the use of a controller (see Digital Plotting of Graphic Data in
Section 2.9).
Stand Alone Plot Output Mode: PPM Internal Procedures:
These actions are performed by the PPM when the Stand Alone Plot is initiated from the front panel.
Before the PPM can output plotter information, it is necessary to first enter the Graph Mode of operation.
Chapter 2 of this manual contains the information required to prepare for and produce digital plots of
Graph Mode and Marker sub-mode data. The following paragraphs describe the PPM’s internal
procedures for GPIB interaction when front panel plots are to be made.
3-10 Manual No. 20790, Rev C, November 1998
Superceded by Revision D, March 2009