Endress+Hauser promag 31, Operating Manual

Page: 31 / 60

➤
Current range
Works setting: 4...20 mA
Switch No. 4: OFF
The current at zero flow (Q = 0) can be set to 0 or 4 mA. The current for the full-scale
value is always 20 mA. Extension to 20.5 mA is possible.
Note!
With the fiscal Promag 31 the switch is always in OFF-position.
Note!
The Promag 31 measuring system can be operated in a bidirectional or unidirectional
mode. Selecting this mode is dependent on the status output and functions as follows:
➤
Pulse value
Works setting: at v ~ 2.5 m/s
Switches No. 5, 6, 7: OFF-OFF-ON
The pulse value indicates for what freely selected volume flow an output pulse is
emitted. With an external counter these pulses can be totalled enabling the total
volume flow to be determined.
The pulse-pause ratio is approx. 1:1. The pulse width is limited to a maximum of 2 s
(
≤
0.25 Hz). At f = 400 Hz the maximum pulse width is 1 ms.
For the Promag 31 measuring system eight preset pulse-value steps can be selected
in terms of the nominal diameter. Setting is made by means of three miniature
switches (see Chapter 4.2).
Configuration of status output Operating mode Function
Flow direction
(only for none fiscal measurement
operation!) Bidirectional
•
Continuous current and
pulse output
System and process errors
This type of operation is only used for
fiscal measurement. Unidirectional
•
Current and pulse output for
positive flow direction only
I [mA]
Forward
flow
Reverse
flow
Scaled full-
scale value
(end value) Scaled full-
scale value
(end value)
[Volume/time]
Q
-Q
4...20 mA
0...20 mA
20.5
20
b
a
0
28y
34
Fig. 37
Promag 31 4. Operation and Commissioning
Hauser 31