Oval Smart EX DELTA II Series, Instructions Manual

Page: 24 / 54

D-582-3-E
2
Supply Voltage E (VDC)
R
L
(load Resistance)
1571Ω
1000Ω
250Ω
12V 0 17.25V 33V 45V
7.6 Hookup with Receiving Instruments
The 2-wire signal transmission system used in this flowmeter furnishes DC power to the meter. It serves
as the power lines and signal lines as well with pulse or analog current output.
An OVAL receiving instrument can be coupled directly, but instruments in general which are designed to
accept a voltage signal input require a load resistor connected in series for voltage conversion. Since the
voltage signal level varies with the load resistance value, determine the load resistance value by referring
to the receiving instrument specifications and the acceptable load resistance range shown below.
Communications with a PC (OVAL Smart Communication Unit EL230) requires a 250 to 000 Ω Ioad.
l
In case a voltage input is fed to the receiving instrument
Flowmeter
Preamplifier
GND
PC PC
R
L
DC Power Source
Voltage Signal
(To Receiving Instrument)
NOTE: See page 22 for terminal identification.
Personal Computers
EL230
Smart Communication Unit
Fig. .5
Acceptable Load Resistance Range
Example:
If supply voltage is 2VDC with load re-
sistance 250 Ω in the hook-up above, then
a to 5V DC voltage output is obtained.
CAUTION
If OVAL Smart Communication Unit
EL2310 is to be connected, use it
below 33 VDC in power supply voltage.
Area: Acceptable range for operation
Area: Communicable range
E － 2V
R
L
＝ －－－－－－－
2mA
Output Voltage Signal (V)
Pulse Output ON / OFF (20mA × R
L
) / (mA × R
L
)
Analog Output (mA × R
L
) － (20mA × R
L
)at 0 ～ FS
2
＋
－
＋
－
＋
－