USB-1208FS-Plus-OEM User's Guide
Functional Details
13
The table below shows some possible inputs and the expected results.
Sample inputs and differential results
CH# IN HI
CH# IN LO
Result
–20 V
0 V
Invalid
–15 V
+5 V
Invalid
–10 V
0 V
–10 V
–10 V
+10 V
–20 V
0 V
+10 V
–10 V
0 V
+20 V
–20 V
+10 V
–10 V
+20 V
+10 V
0 V
+10 V
+15 V
–5 V
+20 V
+20 V
0
+20 V
Channel-Gain queue
The channel gain queue feature allows you to set up a scan sequence with a unique per-channel gain setting and
channel sequence. The settings are stored in a channel-gain queue list that is written to local memory on the
device. The gain queue can contain up to eight elements in single-ended mode, and up to four elements in
differential mode.
The elements must be unique and listed in ascending order. An example of a three-element list is shown in the
table below.
Sample channel-gain queue list
Element
Channel
Range
Gain
0
CH0
BIP10V
2
1
CH1
BIP20V
1
2
CH3
BIP4V
5
When a scan begins with the gain queue enabled, the device reads the first element, sets the appropriate channel
number, range, and gain, and then acquires a sample. The properties of the next element are then retrieved, and
another sample is acquired. This sequence continues until all elements in the gain queue have been selected.
When the end of the channel list is detected, the sequence returns to the first element in the list. The sequence
repeats until the specified number of samples is acquired.
Carefully match the gain to the expected voltage range on the associated channel or an over range condition
may occur. Although this condition does not damage the device, it does produce a useless full-scale reading,
and can introduce a long recovery time due to saturation of the input channel.
For more information about analog signal connections
For more information about analog input connections, refer to the
Guide to DAQ Signal Connections
(available
www.mccdaq.com/support/DAQ-Signal-Connections.aspx
Analog output
You can connect up to two analog output connections to
D/A OUT 0
and
D/A OUT 1
. Each channel can be paced
at rates up to 50,000 updates per second. The output range is 0 V to 5 V.
Digital I/O
The device has 16 DIO channels that are configured as two 8-bit ports – Port A and Port B. Port B is high drive.
You can connect up to eight DIO lines to
Port A0
to
Port A7
and up to eight DIO lines to
Port B0
to
Port B7
.
You can configure each port for either input or output. The digital ports are set for input when the device is
powered on or reset.
