Measurement Computing DAC488 v.1 - Manual (Page 39)

DAC488 User’s Manual DAC488 Operation 33
User-Defined System Defaults
The System Defaults ( S ) command is used to save the Calibration Constants in the Non-Volatile RAM. It
may also be used to save a particular configuration of the DAC488 as a power on default configuration. All
system and port commands may be used to configure the DAC488 and then this particular configuration
saved as the power on default configuration.
An application may require the DAC488 to power on in the following configuration:
•
Autorange disabled
•
Waveform Control Mode
•
Interval = 1 millisecond
•
Port 2 selected
•
Range =
±
10 volts
•
Trigger on Group Execute Trigger
The commands to configure the DAC488 in the above configuration and then to save this configuration as
the power on default would be as follows:
PRINT#1,"OUTPUT09;A0 C3 I1 P2 R3 G2 X"
PRINT#1,"OUTPUT09;S1 X"
•
Line 1: A0 disables autoranging, C3 selects Waveform control mode, I1 sets the interval to 1
millisecond, P2 selects port 2, R3 sets the range to
±
10 volts, G2 enables port 2 to trigger on GET .
•
Line 2: S1 saves this configuration as the power on default configuration.
IEEE 488 Bus Support
The DAC488 implements many of the capabilities defined by the IEEE 488 1978 specification. These
capabilities are discussed in the following sections. However, the bus lines (uniline) and bus commands
(multiline) that the DAC488 does not support, or respond to, include the following:
REN Remote Enable (uniline) PPD Parallel Poll Disable
GTL Go to Local PPU Parallel Poll Unconfigure
LLO Local Lock Out TCT Take Control
PPC Parallel Poll Configure
Bus Lines
The following IEEE 488 bus management lines are supported by DAC488:
•
Interface Clear ( IFC ): IFC places the DAC488 in the Talker/Listener Idle State.
•
Service Request ( SRQ ): Whenever the DAC488 generates a Service Request ( SRQ ), a Serial Poll will
return a Serial Poll Status byte of at least 64 (decimal) showing that the SRQ was generated by the
DAC488. The following BASIC program illustrates one approach for handling service requests:
PRINT#1,"SPOLL09"
INPUT#2,SRQ09 Serial poll the DAC488
IF SRQ09 < 64 THEN GOTO 500 SRQs disabled
IF SRQ09 = 65 THEN GOTO 600 DAC port 1 ready routine
IF SRQ09 = 66 THEN GOTO 700 DAC port 2 ready routine
IF SRQ09 = 68 THEN GOTO 800 DAC port 3 ready routine
Note: To allow the DAC488 to detect each of the above conditions, the Service Request Mask ( M )
command must be enabled for each condition. More extensive tests of the Serial Poll Status
Byte are needed if multiple
SRQ conditions are selected. For more details, refer to the Service
Request Mask ( M ) command in Chapter 7.