Doran GuardianXL, Инструкция по установке и эксплуатации

Страница: 74 / 87

73
4-20mA Setup
To setup the Digital I/O 4-20mA option set the Print Mode parameter to “F3” see Chapter
4 for details. The 4-20mA option is automatically calibrated for an output range of 4mA
to 20mA, (i.e. 4mA equals zero gross weight and 20mA equals the scale’s capacity). If
the scale is in a fault condition, the 4-20mA output levels are 3.5mA for gross underload
or underload, and 24mA for gross overload or overload.
Once the scale has been configured, attach the output cable from the appropriate
controller or indicator to the 4-20mA option board as seen in figure 10.1. A two
conductor cable (Belden #B9740) must be used with an outside diameter of 0.16” to
0.31” to allow for a proper watertight seal. Be sure to connect the polarity of the
controller or indicator properly to ensure proper operation.
If your application requires a self powered (Active mode) analog output, place jumpers
on pins 3,4 (ACT) on JU1 and JU2 as shown in figure 10.2. For loop power (Passive
mode) applications, place jumpers on pins 1,2 (PAS) on JU1 and JU2. See Figure 10.3
for jumper locations.
Calibrate the receiving process indicator or controller according to the manufacturer's
instructions. The 4-20mA output can be forced to 4mA and 20mA in a test mode. This
prevents having to load a scale base to full capacity in order to calibrate the 20mA output.
For details on the test mode see Chapter 4 Scale Test Mode.
Output impedance range of the 4-20mA option is zero to 600 ohms
.
Figure 10.2 Active mode
Jumper settings
Figure 10.3 Passive mode
Jumper settings