Rice Lake SCT-30 - Manual (Page 8)

4 SCT-30 Weight Transmitter Manual
1.1.6 Load Cell Testing
Load Cell Resistance Measurement (Use a Digital Multimeter):
• Disconnect the load cells from the instrument and check that there is no moisture
in the load cell junction box caused by condensation or water infiltration. If so,
drain the system or replace it if necessary.
• The value between the positive signal wire and the negative signal wire must be
equal or similar to the one indicated in the load cell data sheet (output resistance).
• The value between the positive excitation wire and the negative excitation wire
must be equal or similar to the one indicated in the load cell data sheet (input
resistance).
• The insulation value between the shield and any other load cell wire, and
between any other load cell wire and the body of the load cell, must be higher
than 20 Mohm (mega ohms).
Load Cell Voltage Measurement (Use a Digital Multimeter):
• Remove weight of scale from load cell to be tested.
• Make sure that the excitation wires of the load cell connected to the instrument is
5 Vdc +/- 3%.
• Measure the millivolt signal between the positive and the negative signal wires
by directly connecting them to the multi-meter, and make sure it reads between 0
and 0.5 mV (thousandths of a volt).
• Apply load to the load cell and make sure that there is a signal increment.
If one of the above conditions is not met, please contact the
technical assistance service.
1.2 Specifications
• Analog/serial weight transmitter suitable for assembly on back panel fitted
Omega/DIN rail. Dimensions: 90x93x65 mm.
• Current or voltage 16 bit analog output.
• RS-485 serial output with Modbus RTU or continuous transmission protocol.
• Zero and full scale setting.
• Simultaneous display of the load cell reading in mV and of the analog output
reading.
• Operating mode selection via 3-position selector switch, DIP switches, knob
control and 2 line, 8 column alphanumeric display.
Important
ANALOG OUTPUT
(Current and Voltage)
PLC
MAX 8 LOAD CELLS IN
PARALLEL
RS-485
Modbus RTU
SERIAL PORT
DC power
supplier
(12-24 Volt )