Rockwell-automation T3420AF ICS Regent Analog Input Modules Instrukcja Użytkownika Pobierz pdf (Strona 28)

Analog Input Modules

(T3420A, AF)

Industrial Control Services

Programming Fault Tolerant Analog Inputs

To program fault tolerant configurations using triplicated

analog input modules, a midvalue element can be used as

shown in Figure

Figure

. Programming Fault Tolerant Analog Inputs.

In this illustration, VALUE_A_NAME, VALUE_B_NAME,

and VALUE_C_NAME represent the three analog inputs to

be mid

value selected. ERROR_A_NAME,

ERROR_B_NAME and ERROR_C_NAME are the error bits

for the analog inputs. RESULT_NAME is the result of the

mid

value instruction. The field Limit is the integer value, in

similar units to the Value A, B and C variables, that an

analog input can deviate from the mid

value res

ult before

signaling an error (via the Error A, B or C bits). Once an

error bit is set, it is latched. RESET_NAME is the reset bit

used to reset the latched error bits.

Maintenance

There are no user

replaceable parts inside the module.

Modules must be calibrated for the particular input range

within which they will operate. All modules are calibrated

before being shipped by ICS; however, modules require

calibration whenever:

the module is configured for a different operating voltage

range (factory configuration is 1 to 5 VDC),

the module is configured for a different operating mode

(factory configuration is 16 channel, single

ended), or

once per year after installation, to adjust for drift in the

analog circuitry. Drift rates are listed under

Specifications, below. These drift rates should be used to

1 2 ... 23 24 25 26 27 28 29 30 31 32 33 ... 38 39

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Rockwell-automation T3420AF ICS Regent Analog Input Modules Instrukcja Użytkownika Strona 28