27
Chapter 5. SETTING AND OPERATION
*1.Analog output scaling
(4 to 20 mA output models MCF_______D01____ only)
The output current for the instantaneous flow rate is calculated as follows:
Output current
=
(Indicated flow rate – 4 mA flow rate)
✕ 16 + 4 mA
(20 mA flow rate – 4 mA flow rate)
Where:
4 mA flow rate assignment: Instantaneous flow rate for 4 mA analog output
20 mA flow assignment: Instantaneous flow rate assignment for 20 mA analog
output
• The minimum flow rate output flow is 3.2 mA and the maximum output for nor-
mal flow is 20.8 mA.
Depending on the settings for flow rate assignment, a flow rate reaching the
upper or lower limit of analog output may be output.
• If 4 mA flow rate assignment Ao04 ≥ 20 mA flow rate assignment Ao02, the
fixed output for alarm occurrence is output.
• If the difference between the flow rate assignments for 20 mA and for 4 mA is
smaller than the full-scale flow rate, the resulting lower resolution may make it
impossible to get the desired output.
*2.Event output for instantaneous flow rate
Behavior depends on the setting in function setup C03.
(1) When C03 is set to 01or 04 (instantaneous flow rate upper limit)
If the flow rate exceeds the instantaneous flow rate upper limit, event output
turns on. The point at which event output turns off involves a hysteresis and
is calculated as follows:
Event OFF point = instantaneous flow rate upper limit - hysteresis
Specify the hysteresis as a percentage of the full scale flow rate (%FS).
Note: If the Event OFF point is less than zero, the output turns off at zero.
(2) When C03 is set to 02 or 05 (instantaneous flow rate lower limit)
If the flow rate falls below the instantaneous flow rate lower limit, event out-
put turns on. The point at which event output turns off involves a hysteresis
and is calculated as follows:
Event OFF point = instantaneous flow rate lower limit + hysteresis
Specify the hysteresis as a percentage of the full scale flow rate (%FS).
To Next Page
Loading...
Need help?
General
