Honeywell ST700 User Manual page 84

If the input option is Accum
The Integrator block determines the number of additional counts from the counter input
readings from the last execution.
The difference in count is determined as follows:
•
If the difference between the reading in one cycle and the reading in the preceding
cycle is less than 500,000 or greater than (- 500,000), the difference must be taken as the
variation.
•
If the difference between the reading in one cycle and the reading in the preceding
cycle is greater than or equal to (+500,000), add (-1,000,000), use the result as the
variation.
•
If the difference between the reading in one cycle and the reading in the preceding
cycle is more negative than or equal to (-500,000), add (+1,000,000), use the result as
the variation.
The variation of each input must be multiplied by the value, in engineering units, of each
pulse given by PULSE_VAL1 or PULSE_VAL2, as appropriate. The result is the
increment in engineering units of, for example, mass, volume or energy per block execution.
Net Flow
The Net Flow is calculated by considering the direction of flow. The direction of the flow
is calculated by selecting the parameters REV_FLOW and REV_FLOW2. When the
status is set to True for any of these two parameters, the direction of the flow for that input
is considered (Increment is negative) to be negative and the net flow is calculated by
adding the increments for that cycle of execution.
In order to integrate the difference between the inflow and outflow of a tank, for example,
the second one can be assigned to be negative.
The Net Flow direction to be considered in the totalization is defined in INTEG_OPTS.
The following options are available:
•
FORWARD = Only positive flows (after application of REV_FLOWi) are totalized.
The negative values must be treated as zero. FORWARD is selected when the bit
corresponding to Forward is set to True.
•
REVERSE = Only negative flows are totalized. The positive values must be treated as
zero. The option bit Reverse must be set to True.
Page 70 FOUNDATION Fieldbus ST 700 Pressure Transmitter User's Guide Revision 2.0