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Span value
The span value can be set using the actual flow rate unit (m
3
/h, etc.) and flow velocity unit (m/s).
(1) Setting range
The span value can be set within the range of 0 –1.0 ft/s to 0 – 32.8 ft/s (0.1m/s to 10m/s) in terms
of flow velocity
(The range that detector can measure changes with detector type. The details please refer to
Chapter 15 "specifications")
If you try to set a span value outside of this range, either of the following messages appears
depending on whether it is a high limit or low limit error:
* H. OVER SPEC. (if a value exceeding 32.8 ft/s (10 m/s) is set)
* L. OVER SPEC. (if a value of less than 1.0 ft/s (0.1 m/s) is set)
Try to set a new value again.
In the case of Single range setting, select Range 1 only.
(2) Multi-range setting
To use the multi-range function, select Ranges 1 to 4.
When you set these ranges, the following condition must be observed:
Range 1 > Range 2 > Range 3 > Range 4 (in the case of single direction, multiple ranges)
Range 1 > Range 2, Range 3 > Range 4 (in the case of forward/reverse direction, multiple
ranges)
If you try to set the ranges not conforming to the above condition, the following message appears:
* MULTI RNG ERR
Try to set the ranges again.
In addition, set “0” for the ranges not used.
(3) Influence on count rate (pulse rate)
If the range is changed when the count rate (pulse rate) is already set, pulse output at the time of
100% output may exceed the allowable output range.
If this happens, either of the following messages appears after the ranges are set and the system
goes to the count rate setting.
* H. OVER C RATE or * L. OVER C RATE
Try to set the count rate (pulse rate) again referring to 8.2.15 “Count Rate (pulse rate) and Pulse
Width.”
Unit of span
Range 1 is used to set the unit of span. The unit applies automatically to other ranges of Range 2 to
Range 4 and it is not necessary to set the unit for these ranges separately.
The setting units can be selected from the following units:
•
Flow velocity unit: m/s
•
Flow rate unit:
m
3
/s, m
3
/min, m
3
/h, m
3
/d, l/s, l/min, l/h, l/d, ml/s, ml/min, ml/h, ml/d
If you change the unit, the new span value based on the newly set unit will be automatically
displayed.
