Manual FLOW 38
Page 21 (total 54)
COMAC CAL s.r.o.
Current output
D/A - converter of the FLOW 38 evaluation unit is 16-bit with data recovery per second. The converter
is isolated from the meter by optocouplers.
If the current output is passive, it is necessary to feed the current output from an external power supply.
External power supply U
e
can be 12…24 V.
The loop resistance must not be higher than R = U
e
/ 0,02 (Ω;V).
As standard, it is set in such a way that with the maximum flow Q
max
the loop current is 20mA and with
the zero or negative flow, the loop current is 4mA. The borders can be set by buttons or user software
for all flow directions. In case of loss of power for the meter, it is indicated by 0mA current loop output.
In case of active current loop, an internal 16V galvanically isolated power supply is used in FLOW38
meter.
Current loop wiring connection example:
Passive current loop
Terminal board wiring connection:
Active current loop
Terminal board wiring connection:
