Measurement Computing Serial488/4 - Manual (Page 71)

Section 3 Command Descriptions
3.32
the DIO5 bit is set. An Execute command (X) must be received before the
DIO5 bit can be cleared.
DIO6 DIO6 is set w hen an invalid command is sent to the Serial488/4. The M32
command will enable a Service Request to occur when an invalid command is
received. This bit is cleared after the controller sends a Status (U0), or Error
Query (E?) command and reads the status string from the Serial488/4.
DIO7 When the Serial488/4 generates a Service Request, the DIO7 bit will be set to
a logic one. This is used by the controller to determine that the
Service
Request was generated by the Serial488/4.
DIO8 DIO8 is when the Serial488/4 memory is low. The M128 command enables a
Service Request to occur when the memory low condition is encountered.
This bit is cleared when a memory low condition no longer exists.
Example:
PRINT#1,"CLEAR08"
reset the Serial488/4
PRINT#1,"OUTPUT08;M32X"
select SRQ on Bus error
PRINT#1,"OUTPUT08;F7X"
send an invalid bus command.
ERROR and SRQ LEDs should illuminate
PRINT#1,"SPOLL08"
display should be 112 (64+16+32)
64 denotes the Serial488/4 was the source of the SRQ. 16 denotes the Serial488/4 is
READY for more commands. 32 denotes a Command error. When serial polled, the
SRQ LED will turn off.