Measurement Computing DAC488 v.1 - Manual (Page 29)

DAC488 User’s Manual DAC488 Operation 23
DAC488 Operation 4
Introduction…… 23
Command Groups…… 23
System & Port Commands…… 23
Command Support…… 24
Port Triggering…… 24
Trigger Processing & Trigger Overrun…… 25
Internal Buffer…… 26
Buffer Data…… 26
Buffer Save-and-Restore Program…… 27
Control Modes…… 28
Direct Control Mode…… 28
Indirect Control Mode……28
Stepped Control Mode…… 28
Waveform Control Mode…… 29
Multiple Port Synchronization…… 30
Synchronized Waveforms Program…… 30
Digital I/O Port…… 32
User-Defined System Defaults…… 33
IEEE 488 Bus Support…… 33
Bus Lines…… 33
Bus Commands…… 34
Bus Addresses…… 34
Bus Terminators…… 34
Introduction
The DAC488 provides multiple independently programmable 12-bit plus-sign Digital-to-Analog Converters
(DACs). Three voltage ranges,
±
1,
±
5, and
±
10, are available on a per port basis as well as an autorange
feature which automatically selects the range giving the best resolution for the specified voltage. The DAC
ports may be programmed in terms volts or bits. The resolution per bit on each range is: 250 µV/bit (
±
1 V
range), 1.25 mV/bit (
±
5 V range), and 2.5 mV/bit (
±
10 V range). Volts are programmed with decimal
floating point numbers in the range of
±
10.2375 or
±
1.2375E+1. Voltages may also be programmed in
decimal bits (range =
±
4095) or 16-bit hexadecimal two's complement numbers (range = F001 to 0FFF).
Command Groups
Operation of the DAC488 is accomplished using a set of commands that configure the entire interface as
well as each DAC port. The DAC488 commands can be divided into two main groups: System commands
and port commands.
System & Port Commands
System commands affect the operation of the entire interface and are not specific to a given port.
Meanwhile, port commands only affect the operation of the selected port. The port is selected using the
Port Select (
Pn ) command. The 15 system commands and the 11 port commands are listed below:
System Commands Port Commands
Syntax Name Syntax Name
@ Command Trigger A Autorange
D Digital Output B Buffer Data
E? Query Error Status C Control Mode
G GET Trigger Mask F Buffer Definition
K End-Or-Identify Control H Offset Calibration
M Service Request Mask I Interval
O Output Format J Gain Calibration
P Port Select L Buffer Location
Q External Trigger Mask N Number of Cycles
S System Defaults R Range Select
T Command Trigger Mask V Value Output
U User Status
W Test
X Execute
Y Bus Terminator