Doran 2200 Series, Instruction Manual

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78
4-20mA Analog Output Option
Introduction
The 4-20mA Analog Output Option is used to provide an analog output that is
proportional to the displayed scale weight. Because of the inherent noise immunity
present in a current loop, an isolated 4-20mA analog output is ideal for use in noisy
environments. The 4-20mA analog output option can be used to send weight data to a
process indicator, a simple on/off controller or to a programmable logic controller.
Setup
To setup the 4-20mA Analog Output Option, calibrate the scale if required. The 4-20mA
option is automatically calibrated for an output range of 4mA to 20mA. The option will
output 4mA when the scale display reads zero weight and 20mA when the scale reads
full capacity.
Determine if active (Fig 14.2) or passive mode (Fig 14.3) is required. Active mode
provides the 4-20mA loop power, while the passive mode does not provide the loop
power. Select the active mode by placing jumpers on pins 3,4 (ACT) on JU1 and JU2.
For passive mode, place jumpers on pins 1,2 (PAS) on JU1 and JU2. See Fig 14.1 for
jumper locations.
Attach the output cable from the appropriate controller or indicator to the 4-20mA option
board. The white lead is connected to the “+” terminal of TB2 and the black lead is
connected to the “–” terminal of TB2. Output impedance range is zero to 600 ohms.
Calibrate your process indicator or controller according to the manufacturer's
instructions. The 4-20mA output can be forced to 4mA and 20mA in the test mode
parameter to aid in calibration without the use of test weights. If, after calibration, the
Doran 4-20mA output needs adjustment, see the test mode parameter for adjustment
instructions.
.
Fig. 14.1: 4-20mA Analog Option Board
Active / Passive
jumper settings
Connect
output