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6-Channel F Analog Input MTA
Marshalled Termination Assemblies for ET200M Remote I/O Modules
88
A5E00482820-12
9.4
Operation
The Fail-Safe Analog Input MTA consists of the
•
Main board
•
Two diode boards
•
FET Switch Adapters
The diode board marked
1
(MLFB 6ES7650-1BC51-0XX0 or 6ES7650-1BC50-
0XX0 ) uses 6.2 VDC zener diodes. The diode board marked
2
(MLFB 6ES7650-
1BB51-0XX0 or 6ES7650-1BB50-0XX0) uses 5.6 VDC zener diodes. The FET
Switch Adapters are required to make proper operation possible under all
circumstances.
The two diode boards make maintenance of redundant modules possible. The
diode boards plug in to the main board and can be removed for testing and
maintenance without affecting operation of the input module. The FET Switch
Adapters disconnect the input signals from the FAI module in the event of an I/O
power failure or FAI power failure.
Power is supplied via the two removable power connectors which are retained by
screws and marked
L+A
,
MA
, and
L+B
,
MB
. Each has a LED to indicate the
presence of voltage over 15 VDC. The LEDs are marked
A POWER
and
B
POWER
. There is also a connector (
J3
) for a Power Monitor board used to indicate
the presence of both A and B power. See Section 19,
Power Monitor Board
(6ES7650-1BA02-0XX0).
Incoming power from
A
and
B
is diode OR’d, in
CR106
, to provide the MTA and
the module power from either input source. The output from
CR106
is sent to the
I/O modules via the module fuses and to the channels via the channel fuses.
Module Fuse 1 (
F100
) supplies the I/O Module plugged into
J1
and Module Fuse 2
(
F101
) supplies power to the I/O Module plugged into
J2
.
Each channel has an LED to indicate the presence of power and the fuse status. If
there is no power or the fuse is open, then the LED remains off. If there is power
and the fuse is good, then the LED is illuminated.
Since the modules can only be used with current inputs when in safety mode, there
is no provision on the MTA to allow voltage input operation.
Field Terminals, C (
Ix+)
, Channel – (
Ix
-
)
, Sensor power (
PWRx
) and
Shield (
SHx
), connect to the field devices.
PWRx
is the +24 VDC power feed and
is fused on a channel-by-channel basis. The field termination connector is
removable for ease of wiring maintenance and is retained by friction.
For redundant I/O Modules, the Ix- connects to the I/O modules input via J1 and
J2. If both modules are present, then the diodes on boards 1 and 2 are passive, but
ensure that if either module is removed for maintenance, the input signals to the
remaining module are not interrupted. Redundant operation uses the MTA, two
zener diode boards, two FET switch adapters, and two FAI modules. A simplified
diagram of redundant use of the FAI module and MTA is shown in Figure 9–1
Summary of Contents for ET 200M
Page 8: ...Preface Marshalled Termination Assemblies for ET200M Remote I O Modules 8 A5E00482820 12 ...
Page 16: ...Contents Marshalled Termination Assemblies for ET200M Remote I O Modules 16 A5E00482820 12 ...
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