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Chapter 11 Troubleshooting
This chapter gives a quick guide to problem solving for DCell/DSC devices.
Bear in mind that the quickest way to pin down problems is to usually replace items with 'known good' alternatives.
This also applies to cables, power supplies, devices etc.
LED Indicator
The LED is used to indicate the protocol selection, the device is powered and the Device is
Operating. For correct operation the LED should Flash ON for 100mS then repeat at a rate depending on the
protocol. See table below. If this is not the case then follow the instructions below.
If the LED is OFF check the power supply polarity & voltage. The voltage including any troughs should be above 5.6V
and less than 18V. If the supply polarity and voltage is correct then switch off, remove the strain gauge from circuit
and switch on. If the LED is still off check the current drawn by the device. With no strain gauges should be approx
30mA.
If the LED is permanently ON then contact factory.
If The LED is ON for the majority of time then Flashes OFF for 100mS then a fault exists. This Fault can be read back
using the communications. Likely causes of this are Strain Gauge Integrity error or Limits reached for MVV, CRAW,
SRAW or TEMP. First check the connections to the strain gauge are correct. Next check the input is not over-range
or the limits set for CMIN, CMAX, SMIN or SMAX have not been exceeded.
No Communications
The majority of problems involve a failure to communicate, as there are a number of optional settings that must be
set the same at both ends of the link.
For this reason, any communications application should always check command responses, and flag a problem when
there these responses are not activated.
Possible problems can be categorised according to where in the 'chain' of communication the problem may be. The
typical chain runs as follows,
• PC software (port connection, baud rate, station number, protocol)
• PC USB (working)
• PC CAN drivers
• USB-CAN device
• Bus wiring
• Device (wiring, ID, bit rate, working)
Bad Readings
The cause can be either hardware or software related.
Software
1. Check the MVV reading first and ensure it is correct. This figure is the RAW input and is not affected by the user
configurable calibration settings.
2. If MVV looks correct, check the calibration settings step by step.
Consider resetting all the calibration controls to default values – see Calibration Parameters Summary and
Defaults in Chapter 4 The Readings Process. Hardware
3. Load Cell problem should be indicated by Flag LCINTEG in STAT.
4. Genuine hardware problems usual show up as total failure – i.e. no reading = always unchanging, usually near
zero, sometimes always full-scale.
Check wiring, take voltage level readings and again if possible use a known good device and set up.
5. Check the sensor is connected properly, and has some resistance across excitation wires, and around 350 Ohms
across output wires (when disconnected from device).
6. Check for damaged DCell/DSC device by replacement
Mantracourt Electronics Limited DCell & DSC MantraCAN User Manual
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