Sierra INNOVA-MASS 241-VTP - Manual (Page 35)

Series 24-HP Instruction Manual Chapter 2 Installation
IM-24-HP 2-21
Figure 2-18. Non-Isolated 4–20 mA Output Using Meter Input Power Supply
Figure 2-19. Isolated 4–20 mA Output using Meter Provided Power Supply
Pulse Output Connections
The pulse output is used for a remote counter. When the preset volume or
mass (defined in the totalizer settings, see page 3-8) has passed the meter,
the output provides a 50 millisecond square pulse.
The pulse output optical relay is a normally-open single-pole relay. The
relay has a nominal 200 volt/160 ohm rating. This means that it has a no-
minal on-resistance of 160 ohms, and the largest voltage that it can with-
stand across the output terminals is 200 volts. However, there are current
and power specifications that must be observed. The relay can conduct a
current up to 40 mA and can dissipate up to 320 mW. The relay output is
isolated from the meter electronics and power supply.
There are three connection options for the pulse output–the first with a sepa-
rate power supply (Figure 2-20), the second using the flow meter power
supply (Figure 2-21)(DC powered units only), and the third using the inter-
nal 24 VDC power supply (Figure 2-22)(AC powered units only). Use the
first option with a separate power supply (5 to 36 VDC) if a specific voltage
is needed for the pulse output. Use the second configuration if the voltage at
the flow meter power supply is an acceptable driver voltage for the load
connected. (Take into account that the current used by the pulse load comes
from the meter’s power supply). Use the third configuration if you have an
AC powered unit only. In any case, the voltage of the pulse output is the
same as the voltage supplied to the circuit.