Analog input module field devices – Rockwell Automation 1715-OF8I Redundant I/O System User Manual User Manual
Page 98
98
Rockwell Automation Publication 1715-UM001C-EN-P - March 2014
Chapter 2
Installation Instructions
When an analog input module is configured as dual, the analog field loop
connected to channel 0 is automatically fed to both modules. The system
automatically votes the data from the input modules so that you have only one
value presented to the application. The application program is presented with
channel 0 and channel 1 values in a fault tolerant manner so that if either input
module is lost, both values are still available to the application program.
Figure 49 - 1715-TASIF16 and 1715-TADIF16 Analog Input Termination Assemblies
Analog Input Module Field Devices
If there are two field devices, you normally connect them to two channels of a
fault tolerant pair of modules, for example to channel 0 and to channel 1.
The two input values (0 and 1) then need to be voted by using logic or a function
block in the application program. This is accomplished by taking either the
lowest or highest value, depending on the application. The other option is to use
the two values in two simplex input modules, for example, both using channel 0.
In this case, the values still need to be voted in the application program in the
same way as previously stated, but the system has less fault tolerance, as the loss of
one module removes one of the inputs.
32120 M
Fuse
Fuse
Holder
Channel -
Channel +
TB1
TB2
CH0 CH1 CH2 CH3 CH4CH5 CH6 CH7 CH8CH9 CH10CH11CH12CH13CH14CH15
FS1
FS3
FS5
FS7
FS2
J1
16
c
c
c
c
1
1
1
1
16
16
16
J2
J4
J3
FS4
FS6
FS8
FS9
FS11
FS13
FS15
FS10
FS12
FS14
FS16
FH1
FH2
FH7
FH6
FH5
FH4
FH3
FH9
FH8
FH10
FH16
FH15
FH14
FH13
FH12
FH11
FH1
F1
OV OV CH0 CH1 CH2 CH3
CH4 CH5 CH6 CH7 CH8 CH9
CH10 CH11 CH12 CH13 CH14 CH15
TB1
TB2
J1
J2
16
16
1
1
1715-TADIF16
Analog Input Duplex
Termination Assembly
1715-TASIF16
Analog Input Simplex
Termination Assembly
45238
32120-M
Terminal Block Cable This Side
Field Connections This Side
Fuse Cover
Fuse Covers
Polarizing
Pins
Polarizing
Pins