2–14
How Communication Takes Place and I/O Image Table Mapping
Publication 17946.5.5 - October 1996
Memory Map of Analog Output Module Image Table –
1794-OE4
Dec. Bit 15
14
13
12
11
10
09
08
07
06
05
04
03
02
01
00
Size
Oct. Bit 17
16
15
14
13
12
11
10
07
06
05
04
03
02
01
00
Size
PU
Not used - set to 0
W3
W2
W1
W0
Read Word 1
S
Analog Data - Channel 0
Write Word 1
S
Analog Data - Channel 1
Write Word 2
S
Analog Data - Channel 2
Write Word 3
S
Analog Data - Channel 3
Write Word 4
Not used - set to 0
OE3 OE2 OE1 OE0
Write Word 5
Not used - set to 0
C3
C2
C1
C0
Not used - set to 0
F3
F2
F1
F0
Write Word 6
Not used - set to 0
Write Words 7
thru 14
Where: PU = Power up bit - included in series B modules only.
W = Diagnostic bits for current output wire broken or load resistance high. (Not used on voltage outputs.)
S = Sign bit (in 2's complement)
OE = Output enable bits (bit 00 corresponds to output 0, bit 01 corresponds to output 1 and so on.
ATTENTION: These bits must
be set to 1.
C = Configure select bit
F = Full range bit
Range Selection Bits for the 1794-OE4 Analog Output Module
(Write Word 6)
Channel No.
Channel 0
Channel 1
Channel 2
Channel 3
F0
C0
F1
C1
F2
C2
F3
C3
Decimal Bit
00
08
01
09
02
10
03
11
4-20mA
0
1
0
1
0
1
0
1
0-10V dc/0-20mA
1
0
1
0
1
0
1
0
10 to +10V dc
1
1
1
1
1
1
1
1
Off
1
0
0
0
0
0
0
0
0
C = Configure select bit
F = Full range bit
1
When configured to off, individual channels will return 0V.
Word/Bit Descriptions for the 1794-OE4 Analog Output Module
Word
Decimal Bit
Definition
Bits 0003
Current outputs only - When set (1), the wire on the output is
broken or the load resistance is too high. Bit 00 corresponds to
channel 0, bit 01 corresponds to channel 2, and so on.
Read
Bits 0414
Not used - set to 0.
Read
Word 1
Bit 15
Power Up bit - included in series B modules only. This bit
is 0 in series A modules. This bit is set to 1 when all bits in
the configuration register are 0 (unconfigured state).
The
configuration register can be cleared by either of the reset
inputs, or by the user writing all zeroes to it.