Micromod Micro-DCI: 53MC5000 Multi-Loop Process Controller Installation - Manual (Page 66)

3.4.9 TREND MODULES
Eight Trend Modules are present in the controller. Each module provides storage of the last 80
samples of the specified input. The available parameters are shown below. The first four modules
are attached to the CON modules if the CON modules’ trend rate parameter is non-zero. As long
as the trend is attached to the CON module the height rate, mode, span, zero and designator pa-
rameters are overwritten with the values from the CON module.
TREND ZERO and SPAN:
The values assigned to these parameters indicate the lowest value in engineering units displayed
as 0 in the trend and the SPAN in engineering units which corresponds to the height of the trend
display. Samples outside this range will be recorded as at the limits.
TREND POINT DESIGNATOR:
This designates the datapoint to be recorded. It can contain any L, B, C or H datapoint specifier.
When controlled by the CON module this parameter is set to the datapoint specifier which is the
PV of the associated CON module.
TREND ENGINEERING UNIT:
Each trend provides for a 10 character word to indicate the units of measure which are being
trended.
TREND TAG:
Each trend allows for a 10 character name to be associated with it.
TREND RATE:
This parameter defines the recording rate in seconds of the selected datapoint. Legal values are 1,
2, 3, 4, 5, 6, 10, 12, 15, 20, 30 and 60 seconds. If a value which is not legal is entered it will be re-
duced to the nearest legal value. A value of 0 turns off the trending.
TREND MODE:
This parameter specifies the sampling method used to record the selected datapoint. The datapoint
is continually sampled at a one second rate regardless of the trend rate value. The recorded value
can then be a representation of all samples between recording periods.
The available representations are:
0 - Instantaneous value
1 - Average value
2 - Maximum value
3 - Minimum value
TREND HEIGHT:
This specifies the displayed height assigned to a full scale sampled value. This in turn determines
the resolution of the trend and the size of the trend in the front display. When controlled by a CON
module this value is fixed at 50.
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