The 4-20 mA analog output of the SL-7510 scale is a voltage sourcing sensor that will output current which is proportional to the calibrated scale's weight range (i.e. 4 mA = 0 LBS and 20 mA = 10,000 LBS).
It is important to note, that this is a sourcing output sensor (i.e. the sensor will source 9VDC with an output current range of 4-20 mA).
Unlike many other “loop powered” type 4-20 mA
sensors, an external supply voltage should not be connected to the unit's 4-20 mA circuit, however, the ground connection (pin 6) of the DB-9 connector will need to be connected to the same ground as the data acquisition device which will be responsible for interoperating the 4-20 mA signal.
Please reference Figure 6 as a visual clarification on how to connect your scales 4-20 mA output to a data acquisition device.
Below is a list of important notes when using the indicator with the 4-20 mA option
●Resolution: 1/1000
●Outside Load: 100-350ohms
●Inside connection: load input port pin “1” of J2, ground port pin “GND” of J2
●Outside connection: load input port pin 1 of DB9, ground port pin 6 of DB9
●To test the connection, connect a 250 ohm load; Locate a voltmeter and probe across the 250 ohm load. As the weight input to the indicator varies, the voltage of the voltmeter will change accordingly
●Pressing the TARE key will reset to output current to 4mA
●0-20mA output can be set by setting parameter C31 to 0
●Please note that this option will disable the RS232 weigh data output (serial ASCII data ) that comes in the standard indicator.
Calibration:
●Press the PRINT and HOLD key to go into configuration mode
●Go to C32 and press the PRINT key
●The display should show [out-4] and output should be at 4mA
●Press the up/down arrow keys and the [out-#] will increase/decrease