4-20Ma Hook-Up; Opto-Isolated Pulse Output Hook-Up - McCrometer ProComm Max Installation, Operation And Maintenance Manual

3.6

4-20mA Hook-Up

Output type: 4-20mA current loop, sink powered (passive)
Output type: 4-20mA current loop, source powered (active)
If the external device requires a voltage input, a precision resistor placed across the input terminals of the external device
will change the current to voltage. Calculate the required resistor using Ohm's law (V = I x R). For example, a 250Ω resistor
will provide an input voltage of one to five volts with the transmitter range being set from 4mA to 20mA. An additional
4-20mA loop output is available.
Meter source power is 12V for loop power. Max resistance with source power is 300 ohms. Sink power supplied for loop
from external device range is 12 – 30 V DC. Max resistance with external sink power is Rmax = 50 * (V in – 5 )
I
IMPORTANT
The 4-20mA output can be sink or source powered which is selectable in the menus. Default setting is source powered
to avoid damage to the circuit. Do not select source powered if the 4-20 loop has sink power from the 4-20 instrument.
3.7

Opto-Isolated Pulse Output Hook-Up

The outputs are open collector solid state relay outputs used to communicate with or activate external devices.
• Opto-isolated solid state relay open collector
• Maximum switching voltage: 80 VDC
• Maximum switching current: 8 ohms
• Isolation from other secondary circuits: 500 V
• Pulse width range 5ms – 1 second
Figure 16. 4-20mA Hook-Up
CABLING AND CONNECTING WIRING
4-20mA - Terminal 21
4-20mA - Terminal 22
4-20mA - Terminal 21
4-20mA - Terminal 22
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30126-48 Rev. 1.0 | 23AUG2024