Rosemount 8712C - Connect Pulse Output Power Source

2-11
Installation
Connect Pulse Output
Power Source
The pulse output function provides an optically isolated switch-closure
frequency output signal that is proportional to the flow through the
flowtube. The signal is typically used in conjunction with an external
totalizer or control system. The following requirements apply:
The pulse output option requires an external power source. Complete
the following steps to connect an external power supply.
1. Ensure that the power source and connecting cable meet the
requirements outlined above.
2. Turn off the transmitter and pulse output power sources.
3. Run the power cable to the transmitter.
4. Connect –dc to terminal 6.
5. Connect +dc to terminal 5.
Refer to Figure 2-8 and Figure 2-9.
FIGURE 2-8. Electromechanical Totalizer/Counter
FIGURE 2-9. Electronic Totalizer/Counter without Integral Power Supply
Supply Voltage: 5 to 24 V dc
Load Resistance: 1,000 to 100 k ohms (typical
' 5 k)
Pulse Duration: 0.5 to 100 m/sec (adjustable)
Maximum Power: 5.75 watts
Switch Closure: transistor, open collector, PNP
8712-8712|11A
Electro-
mechanical
Counter
5–24 V dc
Power
Supply
+ –
––
+ +
8712-8712|11B
Electronic
Counter
5–24 V dc
Power Supply
1k to 100 k
Typical ' 5k
–
+
+
–
+
–