Cleveland Motion Controls Classic Series DIN Rail Amplifier with Isolated Output MWI-13467 REV CA - Manual (Page 17)

MAN-13467 R EV CA C LASSIC S ERIES A MPLIFIER W / I SOLATED O UTPUTS
Page 17 of 30
2.12.2.1 4 TO 20 M A A NALOG C URRENT L OOP
The 4-20 mA current loop output is undamped and can be used concurrently with the other outputs. The 20 mA
current level corresponds to the +10V output. The 4 mA level corresponds to 0 volts on the 10V output.
This output does not have an individual Gain and Zero Potentiometer adjustment. If multiple types of analog output
are being used, a compromise must be made during calibration, or a particular output be favored (over one that can
best accommodate individual external scaling and offsetting ).
The bias supply to drive the current loop is provided internally by the Classic amplifier. External burden resistance
(loop resistance) can range between 50 and 750 ohms.
The circuitry that drives the current loop is essentially a linear regulator stage. This means that
internal power dissipation (hence temperature rise) is lessened when higher values of external
burden resistance are used. Moderate values of burden resistance can be strategically employed to
minimize internal temperature rise (and thereby minimize amplifier drift in sensitive applications).
8
+
5
7
6
3
4
2
1
1
4
2
3
6
5
7
8
4 to 20 mA
i
+
SHIELD GND
LOOP RESISTANCE
50 - 750 OHMS
Figure 8 - Output Wiring, 4 to 20 mA Analog Current Loop, Floating Burden