Direct Channel
Configuration
Register
The Direct Channel Register allows you to specify channels to be closed
individually. Note that the DIR bit in the Control Register must be set true
for this register to be enabled.
base + 0C
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Write
Undefined
X
X
X
X
D3
D2
D1
D0
D3 - D0
Data bits three to zero. The FET strain gage multiplexer channels and
diagnostics are mapped into bits D3 through D0 as follows:
D3 - D0
0 0 0 0
closes bridge completion channel 0
0 0 0 1
closes bridge completion channel 1
0 0 1 0
closes bridge completion channel 2
0 0 1 1
closes bridge completion channel 3
0 1 0 0
measures the leadwire resistance on bridge completion channel 0
0 1 0 1
measures the leadwire resistance on bridge completion channel 1
0 1 1 0
measures the lower leg of the internal half bridge voltage
0 1 1 1
measures the upper leg of the internal half bridge voltage
1 0 0 0
closes bridge completion channel 4
1 0 0 1
closes bridge completion channel 5
1 0 1 0
closes bridge completion channel 6
1 0 1 1
closes bridge completion channel 7
1 1 0 0
not used
1 1 0 1
not used
1 1 1 0
measures the guard voltage
1 1 1 1
measures the bridge excitation voltage
Direct Control
Register
The Direct Control Register allows you to set the controls for individual
channels. Note that the DIR bit in the Control Register must be set true for
this register to be enabled.
base + 0E
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Write
Undefined
X
X
X
VLD
A_D B_D
C1
C0
C1 - C0
Configuration bits. These bits determine the measurement Mode as listed
below.
C1
C0
0
0
Volts (strain and diagnostic measurements)
0
1
2-wire ohms
B_D , A_D
B and A Tree Isolation Switch disable. A zero (0) in either one disables
the respective Tree Isolation switch. Generally both disabled together to
equal the
SCAN:PORT NONE
command.
VLD
Valid Channel. A zero (0) indicates that the channel is valid. The DIR bit
in the Control Register automatically sets this bit. If DIR is valid and IRQ
EN is true, a write to this register will generate an interrupt.
132 Strain Gage Register-Based Programming
Appendix D
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com