Measurement Computing DAC488 v.1 - Manual (Page 83)

DAC488 User’s Manual DAC488 Commands 77
Q - External Trigger Mask
TYPE System Command
SYNTAX Qmask Set bit(s) in the External Trigger Mask to specify which ports will be triggered by an
external trigger event. The mask bits are as follows (bit values are shown in
parenthesis):
• Bit 1 = Enable trigger to DAC port 1. (decimal value 1)
•
Bit 2 = Enable trigger to DAC port 2. (decimal value 2)
•
Bit 3 = Enable trigger to DAC port 3. (decimal value 4) (DAC488/4 only)
• Bit 4 = Enable trigger to DAC port 4. (decimal value 8) (DAC488/4 only)
•
Bit 8 = External input edge sense: 1 = negative edge triggered;
0 = positive edge triggered. (decimal value 128)
Q-mask Clears the specified bits in the External Trigger Mask.
Q0 Clears all bits in the External Trigger Mask.
Q? Returns current External Trigger Mask.
DESCRIPTION
The External Trigger Mask command enables or disables the specified DAC port for triggering by an external trigger
signal. The external trigger signal is applied to the External Trigger/SRQ input on the digital I/O port.
Note: The default value for all bits is 0.
EXAMPLE
PRINT#1,"CLEAR09" Line 1: Reset the DAC488.
PRINT#1,"OUTPUT09;C1 Q129
P1 A0 R2 V2 X"
Line 2: Select Indirect Control mode, enable port 1 for triggering by an
external trigger signal, trigger on negative edge of external trigger signal,
select port 1, disable autoranging, select 5 volt range, output 2 volts.
Port 1 will output 2 volts when an external trigger pulse is applied. (Port
1 will trigger on the negative edge of the external trigger pulse).
PRINT#1,"OUTPUT09;Q-12 X" Line 3: Clear bits 3 and 4 of External trigger mask to disable triggering of
ports 3 and 4 when an external trigger pulse is received.