Measurement Computing PCIM-DDA06/16 - Manual (Page 11)

PCIM-DDA06/16 User's Guide Installing the PCIM-DDA06/16
Simultaneous transfer jumper
The simultaneous transfer jumper controls whether to update DAC channels individually (default) or as a
group. This jumper is shown in configured in its default
UPDATE
position. Figure 2-1
Figure 2-1. Simultaneous transfer jumper
XFER
UPDATE
ƒ Set the jumper to
XFER
to update the DAC voltage outputs as a group.
New output data is held until all DACs are loaded with their new digital data.
The data for each DAC is simultaneously transferred and the DAC voltage outputs are updated as a group
when any of the addresses BADR3 + 0 to BADR3 + B are read. Writing new digital values to the DAC
control register does not cause an update of the DAC's voltage output. Update of the output occurs only
after the DAC control register address (any of the addresses BADR3 + 0 to BADR3 + B) is read
In this way, the PCIM-DDA06/16 can be set to hold new values until all channels are loaded, then update
all six channels simultaneously. This is a very useful feature for multi-axis motor control.
ƒ Set the jumper to
UPDATE
to update the DAC voltage outputs individually.
The analog outputs are controlled by writing a digital control word as two bytes to the DAC's control
register. The control register is double-buffered, so the DAC output is not updated until both bytes (first
low byte, then high byte) are written to the DAC control register when the simultaneous transfer jumper is
in the default
UPDATE
position.
Analog output range switch
You set the analog output voltage range of each with a five-position DIP switch. The switches are located on
the board directly above the DACs and are labeled
CH5
through
CH0
(
S6
through
S1
). Bipolar ranges are
±10 V and ±5 V. Unipolar ranges are 0 to 10 V and 0 to 5 V.
Figure 2-2
Figure 2-2. Analog output range switch—one per DAC
lists the range value and associated settings for each switch.
Range
±
±
10
5.0
0-10
0-5
1
D
D
U
U
2
U
U
D
D
3
D
D
U
U
4
U
D
U
D
5
D
U (shown)
D
U
To set a channel to a particular range, read the switch positions as
U
(up) or
D
(down) from left to right in the
row beside the range you want to set.
2-3