Measurement Computing Serial488/4 - Manual (Page 52)

Section 3 Command Descriptions
3.13
M128
will generate a Service Request when the Serial488/4 has used up most of
its available memory. This provides an indication that no further data should be sent
to the serial ports until data is freed. Data may be freed either by reading serial input
data from the Serial488/4, waiting for serial output data to finish being transmitted, or
by flushing a serial port if data is not moving as expected.
Example 1: Enable SRQ on serial data or low memory using dual primary addressing
mode.
PRINT#1,"OUTPUT08;M0X" clear SRQ mask
PRINT#1,"OUTPUT08;M1X"
select SRQ on serial port 1 data
PRINT#1,"OUTPUT08;M2X"
select SRQ on serial port 2 data
PRINT#1,"OUTPUT08;M4X"
select SRQ on serial port 3 data
PRINT#1,"OUTPUT08;M8X"
select SRQ on serial port 4 data
PRINT#1,"OUTPUT08;M128X"
select SRQ memory low
Example 2: Enable SRQ on serial data or low memory using dual primary addressing
mode. This example has the same effect as example 1.
PRINT#1,"OUTPUT08;M132X"
select SRQ on serial data or memory low
Example 3: Enable SRQ on error using secondary addressing mode.
PRINT#1,"OUTPUT0800;M0X"
clear SRQ mask
PRINT#1,"OUTPUT0800;M32X"
select SRQ on command error