Dynalco LMD-120A User Manual

Signal Powered Digital Indicator

LMD-120A

Installation and Calibration

The LMD-120A is powered from the 4-20 mA current that serves as the signal into
terminals 1 (+) and 2 (–). Do not make any other power connections to this unit.

K

This device can be connected as a simple current meter in any 4-20 mA current

loop in series with transmitters, controllers, and other 4-20 mA monitors.
Maximum loop burden is 100 ohms at 20 mA.

Calibration:

1. With 4 mA input, adjust ZERO ADJUST for desired reading at 4 mA.

2. With 20 mA input, adjust SPAN ADJUST for desired reading at 20 mA.

3. Repeat steps 1 through 2. Recalibrate as needed.
Note: With switch 4 off, ZERO ADJUST permits any initial reading from
–1000 to +1000; SPAN ADJUST permits a span adjust from 100 to 2000 counts.

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With switch 4 on, the zero is adjustable from –10,000 to +10,000; the span is
adjustable from 1000 to 20,000 (fixed zero).

Intrinsic Safety: This instrument is CSA certified as intrinsically safe for Class I,

Divisions 1 and 2, Groups A, B, C, and D hazardous locations, if the signal feeding
the unit is derived from a safe source or through a safety barrier meeting entity
parameters of Vmax = 40 volts, Imax = 200 mA, Ci = 0, Li = 0.

© 2002 Dynalco Controls 145F-12032, Rev. 0

LMD-120A — View with the plug removed

Calibration controls under plug (rear)

Switches 1, 2, and

3 control decimal

points as shown.

Dynalco Controls, 3690 N.W. 53 St.
Ft. Lauderdale, FL 33309 USA
[phone] • Fax [phone]
www.dynalco.com • [e-mail]

Switch 4 adds a dummy
zero (fifth digit, fixed
zero) to extend range
1999 to 19990.