Emerson FB2100, Инструкция по эксплуатации

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Emerson FB2100 Flow Computer Instruction Manual
D301783X012
March 2019
I/O Configuration and Wiring 65
Table 3-4. Digital Output Characteristics
Type Number Supported Characteristics
Digital
Output
(DO)
1 (CPU option 1)
0 to 2 (CPU option 2) as follows:
▪
1 or 2 non-isolated channels on CPU
board (DI/DO/PI 1 and DI/DO/PI 2). Two
always present; you can configure one,
both, or neither as DOs.
▪ DO is a low side switch that sinks current
to ground
▪ Current rating of 500 mA (see note
below)
▪
Maximum operating frequency of 50 Hz
▪
Pulse off/on time can be configurable
with a 31 ms minimum on time and a 31
ms minimum off time
▪
Can be configured in software with an
output state for initial power-up and in
the case of a CPU failure
▪
Software configurable failure mode of
fail open, fail closed, or hold last state
▪
When a channel is configured as a DO it
cannot be used as a DI or PI channel
Note
Digital outputs are rated to 500mA maximum. In a small number of applications, however, the load
on the DO
could have an effect on the uncertainty of the analog inputs and outputs. The typical
increase in uncertainty is around 0.05% and only occurs when all of the following are true:
▪ Either of the two analog channels in the base I/O is used as an AI (in voltage mode) or as an AO
and
▪
Either of the two digital channels in the base I/O is used as a DO and
▪
The total current load on these two DOs is greater than 300mA
▪
Analog inputs in current mode and the I/O channels in the expansion I/O boards are not
affected.
3.4.1 DO Wiring
The diagram below shows how to wire the digital output.