Design and Implementation of HC900 Control System - Allowable Function Blocks for Process and Safety Functions
18 HC900 Process & Safety Controller Safety Manual Revision 1.9
01/14
Discrete Output
Provides a digital status from the algorithms and
functions to a physical logic output. Outputs 17
through 32 of the 32 Channel DO Module, may not be
used for TPO (Time Proportioning Output), PPO
(Position Proportioning Output) or TPSC (Three
Position Step Output) output types.
X
Discrete Output
with Feedback
Provides a digital status from the algorithms and
functions to a physical logic output. Feedback
channel validates physical output.
X X
8 Point Digital
Output
Provides write access for up to 8 physical digital
outputs (all written at the same time).
X
Time Prop Out
Proportions the amount of ON time and OFF time of a
Digital Output over a user defined cycle time.
Outputs 17 through 32 of the 32 Channel DO Module,
may not be used for TPO (Time Proportioning
Output), PPO (Position Proportioning Output) or
TPSC (Three Position Step Output) output types.
X
Position Prop
Output
Allows the control of a valve or other actuator having
an electric motor driven by two digital output
channels; one to move the motor upscale, the other
to move it downscale, with a feedback signal to
indicate motor position. Supports motor speeds from
12 -300 seconds. Outputs 17 through 32 of the 32
Channel DO Module, may not be used for TPO (Time
Proportioning Output), PPO (Position Proportioning
Output) or TPSC (Three Position Step Output) output
types.
X
Frequency Input
The function is used for measuring speed and rate. It
reads a single frequency channel from a
Pulse/Frequency/Quadrature input module. The
signal is scaled from the selected frequency span to
the selected output range in engineering units,
providing an output value in engineering units. The
input signal is rejected if it is below a selected pulse
width. The frequency of pulses above this width must
be within the range specified by Pulse Width (Range);
otherwise the output goes to failsafe and a failure-to-
convert error occurs.
X
Pulse Input
This function block reads pulses from a single input
channel on a Pulse/Frequency/Quadrature input
module. It measures quantity by scaling the number
of pulses to engineering units (EU). It measures rate
in engineering units by dividing number of pulses by
time. The preset values, reset, preset action, and hold
flags are sent to the module and the module
responds with accumulated pulse counts, preset
indicator (PREI) (when preset value is reached),
counter overflow indicator (OVFL), and FAIL. The
block converts the accumulated pulse count to EU.
X
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