Cortalk RMU5 Generic Installation And Configuration Manual page 44

source. Low Range signals must be within +/-125mV peak. Medium range signals must be within +/-7V peak.
High range signals must be within +/-175V peak. Typically, the low range is used for measuring a current
shunt.
Fill in the Range and Units fields with meaningful values. The Units field will typically be 'A' for amps.
2.
Press the 'Current Shunt Calc' button. Enter the shunt full scale amps value and the shunt full scale millivolts
3.
value. Click 'Set Parameters'. The channel scaling field will be filled in with the appropriate value for the
shunt.
A 4-20mA transducer outputs a current proportional to the signal being measured. To measure this type of source, the
RMU5 must be fitted with a precision resistor (typically 7.5ohms or 250ohms) between the + and – terminals for the
appropriate input channel. The transducer output signal is then attached to the + and – terminals.
Calibration of 4-20mA transducer inputs requires the following procedure be performed:
For one of the four RMU5 internal analog inputs, set the range selection by pressing the button next to "Select
1.
Range" in the "Analog Input Calibration" group until an appropriate range is selected for the measurement
source. Low Range signals must be within +/-125mV peak. Medium range signals must be within +/-7V peak.
High range signals must be within +/-175V peak. Typically, the low range is used for measuring a current
shunt.
Fill in the Range and Units fields with meaningful values. The Units field will typically be 'A' for amps.
2.
Press the '4-20mA Transducer Calc' button. Enter the values for the external shunt resistor, the measurement
3.
value when the transducer output is 4mA, and the measurement value when the transducer output is 20mA.
Click the 'Set Parameters' button. The 'Channel Offset' and 'Channel Scaling' fields will be filled in with the
appropriate values for the 4-20mA transducer. The range will also have been automatically set to match the
external shunt resistor being used.
Note: When communicating measurements over the Easytrack satellite communicator, it is possible to indicate
to the back-end host that a channel is disabled by setting the channel scaling field to a value of 0.
MOBILTEX® DATA LTD.
Calgary, Alberta
TITLE:
RMU5 Generic Installation and Configuration Guide
DOCUMENT NO.: SHEET:
RMU5-MAN-001
REV:
44 of 69 1.10