Rockwell Automation T80004 Application Note Field Loop Configuration - Manual (Page 33)

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TM
AN-T80004 Field Loop Configuration
Issue 10 Jun 13 AN-T80004 33
V_FIELD_GRP1
V_FIELD_RTN_GRP1
F
I
E
L
D
T
E
R
M
I
N
A
L
S
V_FIELD_RTN_GRP1 ( SK1 AND 2 )
V_FIELD_GRP1
PWR
TERMINALS
CHAN _1_V_FIELD_GRP1
CHAN _1_V_FIELD_RTN_GRP1
CHAN _2_V_FIELD_GRP1
CHAN _2_V_FIELD_RTN_GRP1
CONNECTIONS TO
OUTPUT MODULE
CONNECTIONS
FROM
OUTPUT
MODULE
TO
THE
FIELD
T8850 and T8870 FTAs
The T8850 and T8870 FTAs are also a simple straight-through connection, but also include power
supply indicating LEDs. However, these are only relevant if using integral power cables, where the field
power is wired to the FTA and connects through the I/O cable to the module. The T8850 is designed
for 24V dc operation but would be appropriate for 48V dc operation if the power supply indicating LEDs
are not connected. The T8870 is designed for 120V dc operation for the T8471. It also includes 330K
resistors across each channel to terminate the T8471 diagnostics. The T8472 requires its own FTA
which is covered later.
Two variants of I/O cable may be used with these FTAs.
‘Integral power’ cables include five 2.5mm 2 wires to carry the field power supply from the FTA back to
the module. These cables are TC-215, 217, 515 or 517. These are appropriate where the power
supplies are fitted near the FTAs in a marshalling panel which is separate or distant to the system.
The power supply positive and negative connections should be connected to the PWR TB terminals on
the FTA. This will also energise the FTA’s power group LEDs, and so this arrangement can only be
used at the rated voltage of the FTA.
Output
module
Field Supply
Load
FTA