Panametrics PanaFlow MV80, User Manual, Page: 57 / 184

PanaFlow™ MV80, MV82 & MV84 User’s Manual 45
Chapter 2. Installation
2.6.5 Alarm Output Connections
One alarm output ( Alarm 1 ) is included on the standard PanaFlow meter. Two or more alarms ( Alarm 2 and Alarm 3 )
are included on the optional communication board. The alarm output is used for transmitting high or low process
conditions, as defined in the alarm settings (see
“The Alarms Menu” on page 80 ).
The alarm output requires a separate 5 to 36 VDC power supply. The alarm output optical relay is a normally-open
single-pole relay. The relay can conduct a current up to 40 mA. It is isolated from the meter electronics and power
supply. When the alarm relay is closed, the current draw will be constant. Make sure to size R
load
appropriately.
There are three connection options for the alarm output:
• For AC or DC powered meters, use a separate 5 to 36 VDC power supply (see Figure 45 on page 45 ). Use this
option if a specific voltage is needed for the alarm output.
• For DC powered meters only, use the flow meter power supply (see Figure 46 on page 45 ). Use this option if the
voltage at the flow meter power supply is an acceptable driver voltage for the connected load, taking into
account that the current used by the alarm load comes from the meter’s power supply.
• For AC powered meters only, use the internal 24 VDC power supply (see Figure 47 on page 45 ). Use this option
if the voltage of the alarm output is the same as the voltage supplied to the circuit.
Alarm +
Alarm –
Pulse voltage = +V
Select resistor so that current
R current limit 10K
through pulse < 40mA
+V
R current limit 10K
AC or DC powered
meters
Figure 45: Isolated Alarm Output with External Power Supply
+ Pwr
– Pwr
DC Power Alarm +
Alarm – DC Common
R current limit ~10K
Alarm voltage = + Power voltage for meter
DC units only
Figure 46: Non-Isolated Alarm Output Using Internal Power Supply
+ 24 VDC Out
– 24 VDC Out
Alarm +
Alarm –
R current limit ~10K
Alarm voltage = + Power voltage for meter
AC units only
Meter provided DC Power
Figure 47: Isolated Alarm Output Using Meter Provided Power Supply