Leslie PMC-1 User Manual

APPENDIX B
CONNECTING 2-WIRE AND 4-WIRE
TRANSMITTERS TO THE PMC-1
Electronic transmitters used to measure pressure, level, and
other variables are classified as 2-wire or 4-wire, depending
on how they are powered. The PMC-1 can be used with either
type of transmitter.
The most common transmitter type is the 2-wire transmitter,
which has one power input wire (24VDC nominal) and one
signal output wire (4-20 mA) . In most cases, there is actually a
third wire leading from the transmitter, but it is still referred
to as 2-wire.
The 2-wire transmitter is connected to the PMC-1 as shown
in Figure 8. Terminal 1 supplies 24vDC power to the
transmitter, and terminal 3 receives the 4-20mA signal back.
11
Terminal 2 is an earth ground.
A 4-wire transmitter needs two additional wires, because it
receives its power from a separate power source. This type of
transmitter can also be used with the PMC-1, and it is
connected as shown in Figure 9. Since it receives its power
from a separate source, terminal 1, the PMC-1’s power is not
used. The 4-20mA signal from the transmitter is connected
to terminal 3, as in the case of the 2-wire transmitter, but the
circuit is completed by connecting the other wire from the
transmitter to terminal 4, circuit common. If the transmitter
is equipped with an earth ground, it should be connected to
terminal 2.
PMC-1
24VDC
Earth Ground
4-20mA
2-Wire
Transmitter
Circuit Common
4-Wire
Transmitter
Power
Source
PMC-1
Earth Ground
4-20mA
* 1
* 2
* Terminal connections for Ashcroft transmitters only

Leslie PMC-1 Specifications

General

Brand	Leslie
Model	PMC-1
Category	Controller
Language	English