63
Binary output:
If the frequency output is set to signal the flow direction, Fct. 3.4.2. is suppressed and the
output is as follows :
Flow Direction
pos.
+ V
neg.
0 Volts
Fig. 35: Frequency output characteristic of examples 1 and 2
6.8
Setting the process alarm output (Status)
The process alarm output is a two state signal (active or inactive) that can be used to indicate
a variety of meter and process states, as shown in the table below.
For all functions it is possible to define whether the output is to be active high, 24 Volts or
active low, 0 Volts (Fct. 3.5.2). The first five functions check measured values against user-
defined limits. While the value is within these limits the Process Alarm output is inactive. If the
value exceeds the limits then the output becomes active. To prevent multiple switching of the
output when the measured value is just on the limits, hysteresis is built in. Refer to Figure 36;
as mass flow increases past the maximum limit the output switches to active. However, as
flow then decreases the output will not switch to inactive until it becomes less than MAX - H
where H = 2% of upper limit.
Process alarm functions:
Function
Inactive
Active
Mass total
Mass flow
Density
Temperature
Volume flow
Concentration by mass *
Concentrationby volume *
Solute Mass Flow Rate*
Current outputs I 1,2 3
Frequency output
Any Output
All status messages
Severe errors
Flow direction
Total in range
Mass flow in range
Density in range
Temp. in range
Volume flow in range
Concentration in range
Concentration in range
Solute flow rate in range
Specified current output OK
Frequency output OK
All outputs OK
No converter errors
No serious converter faults
neg. flow (-ve)
Total out of range
Mass flow out of range
Density out of range
Temperature out of range
Volume flow out of range
Concentration out of range
Concentration out of range
Solute flow rate out of range
Current output saturated
Output saturated
At least one output saturated
At least one error detected
Major converter fault;measurement stops
pos. flow (+ve)
* If concentration option installed.
