How can TU5300sc or TU5400sc communicate when there's an instrument error?

Document ID

Document ID TE7473

Published Date

Published Date 01/13/2022
Question
How can TU5300sc or TU5400sc communicate when there's an instrument error?
Summary
Explanation of how to set up TU5300sc or TU5400sc error communications
Answer
With over 300 continuously running on-board diagnostics, the TU5 Series turbidimeters are able to quickly communicate when an issue occurs. Instrument issues are communicated by:

LED Indicator
In an error state, the indicator light on the front of the instrument turns red and may also flash depending on error severity.

Instrument Event Log
Instrument errors are recorded in the TU5300sc or TU5400sc event log; this can be downloaded directly from the controller or accessed via Network (sc1000 and newer controllers).   

Error Communication via 4-20mA Output
Hach controllers have a function called Error Hold Mode. This function tells the 4-20mA output of the controller to do something when it senses that the TU5 sensor is in error. One of the options is to transfer outputs, which allows for choice of a value to send to SCADA when the instrument is in error. For example, if the instrument was scaled for 0-2 NTU (0=4mA and 2=20mA) , the controller could be set to send out 4mA when an error occurs.

To complete this with the controller:
  1. Use the appropriate controller user manual to choose the Error Hold Mode (sc200) or On Error Mode (sc1000 and above).
  2. Choose Transfer Outputs (sc1000 and above: Set Transfer)
  3. Navigate to Output Setup
  4. Choose the 4-20mA output connected to the TU5 sensor.
  5. Choose Set Transfer and select the current value (suggested 0 or 4mA) that will indicate there's an error with the sensor.
Flow sensor errors (e.g. low flow/no flow) can be set up using the steps above. However, the flow sensor would need to be connected to output its own 4-20mA signal in order for the error to be sent correctly.

Error Communication via Digital Communications (Modbus, Profibus, etc.)
Registers included for digital communications on all Hach sensors and analyzers (Modbus Register 49930) include 16 different bits that communicate instrument errors. More information can be found in the most current version of the TU5 Series Modbus registers, downloadable here.
 

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