User`s manual

Understanding the Relay Multiplexer Modules 41Chapter 4
Chapter 4
Understanding the Relay Multiplexer
Modules
Using This Chapter
This chapter explains techniques to scan the channels of 16-Channel Relay
and 16-Channel Thermocouple Relay Multiplexer Modules.
• Commands for Scanning Switchbox Channels. . . . . . . . . . . Page 41
• Using Scanning Trigger Sources. . . . . . . . . . . . . . . . . . . . . . Page 41
• Using the Scan Complete Bit . . . . . . . . . . . . . . . . . . . . . . . . Page 46
Commands for Scanning Switchbox Channels
Scanning multiplexer channels consists of closing a set of channels, one at a
time. Available for the multiplexers are single, multiple (2 to 32767), or
continuous scanning modes. See Figure 4-1 for the different commands used
in scanning.
Using Scanning Trigger Sources
The TRIG:SOUR command specifies the source to advance the channel list.
Use the
TRIG command to advance the channel list while in the TRIG:SOUR
BUS
or TRIG:SOUR HOLD trigger state. To enable the E1300/E1301
Mainframe "Trig Out" port, use the
OUTP command. Figure 4-2 shows the
different trigger sources. The sources are used in other VXIbus mainframes
with command modules that have "Trig Out" ports.
Scanning with
External
Instruments
The examples on the following pages show different ways to scan channels
of a switchbox in an E1300/E1301 Mainframe. The operation is similar to
other VXIbus mainframes with command modules that have "Trig Out" and
"Event In" ports.
The computer used in the examples is an HP Series 200/300 used with
BASIC as the program language. The computer interfaces with the
mainframe over GPIB. Assumed is an:
-- GPIB select code of 7;
-- GPIB primary address of 09 for the E1300/E1301 Mainframe;
-- GPIB primary address of 22 for the 3457A Multimeter;
-- GPIB secondary address of 14 for the multiplexer module.