AMC 2751 Instruction Manual - Page 10

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4.2 CABLE SELECTION AND WIRING

To pass the 4 to 20mA signal from the AMC-2751 sensor/transmitter to the monitor, a two conductor,

shielded cable is recommended. Note that the same wire pair can be used for both signal and power due

to the low power current loop design of the AMC-2751. For best signal transmission and maximum noise

rejection, it is recommended to run the cable through steel conduit ( the cable must be grounded at the

monitor or power supply).

The AMC-2751 minimum stated voltage requirement of 12 VDC is based on the use of a 250 ohm load

resistor to covert the current signal into a voltage signal. The maximum Cable Distance Chart (Figure 3)

assumes the use of a 250 ohm load resistor, and a safety margin of .5 VDC. It gives absolute maximum

cable lengths for a range of wire gauges. Note that the user must take responsibility for the selection of

wire gage, power supply voltage and load resistor used as the values shown may not be suitable for all

applications.

WIRE GAUGE

R/1000 ft

MAXIMUM

@12VDC

DISTANCE IN

FEET

@24VDC

(METERS)

FIGURE 3: Cable Selection Chart

4.2.1 SENSOR/TRANSMITTER TO MONITOR WIRING

The AMC-2751 sensor/transmitter should be connected to the monitor, as shown in Figure 4, by

a twisted pair cable for the conduction of the 4 to 20 mA signal.

See the following connections going from the AMC-2751 to the monitor for each channel:

AMC-2751 Terminal (+) -------- goes to------- Monitor Channel Terminal (+)

AMC-2751 Terminal (-) -------- goes to------- Monitor Channel Terminal (SIG)

AMC-2751 Transmitter & Sensor

AWG

16.2 ohms

400

(120)

10000

(3000)

(Based on 250 Ohm Load Resistor & V

10.3 ohms

6.5 ohms

700

1000

(210)

(300)

16000

Over 20000

(4800)

(6000)

4.3 ohms

1500

(4500)

Over 20000

(6000)

= .5 V)