Setting prism wash parameters - PR-43-AC - PR-43-AP - PR-43-GC - PR-43-GP - PR-43-PC

MI User Guide
Document code
IM-EN-MI
Revision
D
Language
English
Product
PR-43-AC
PR-43-AP
PR-43-GC
PR-43-GP
PR-43-PC
Document type
User guide

To set prism wash parameters for a given refractometer, first select the Refractometer app, then select Calibration and then Prism wash. This menu contains the alternatives (factory settings are given in parentheses):

  1. Precondition secs 0 … 60 s (0)
  2. Recovery secs 0 … 120 s (20)
  3. Wash secs 0 … 30 s (3)
  4. Empty pipe check (enabled)
  5. Wash check mode (disabled)
  6. Wash verify delta nD limit 0.0 … 0.5 (0.0)
  7. Wash inhibit temp enable (disabled)
  8. Interval mins 0 … 1440 min (20)
  9. Wash inhibit temp value 0 … 200 °C (0)
  10. Wash verify nD limit 1.15 … 1.80 (1.35)
  11. Wash failure tolerance mins 0 … 1440 (0)
  12. Measurement hold during wash (enabled)
  13. Temperature hold during wash (disabled)

The prism wash cycle: The timing of the wash cycle is controlled by the WASH INTERVAL, PRECONDITION TIME, WASH TIME and RECOVERY TIME settings. If the WASH INTERVAL is set to zero, the wash can only be initiated by using the manual wash (PRISM WASH on Diagnostics menu) or general input module configured for external wash.

If the PRECONDITION TIME is zero (or there is no relay configured for preconditioning), the preconditioning phase is skipped. If the WASH TIME is zero (or there is no relay for wash), the wash functionality is completely disabled.

The recommended wash times and wash medium pressures are given in the refractometer manual.

Wash check mode, standard: The prism wash check monitors automatically that the prism wash really has an effect on the prism. In the WASH CHECK mode, prism wash is accepted if the refractive index nD either falls below wash verify nD limit (default 1.35) at Normal operation or NO SAMPLE occurs. This is the indication of a successful wash with water or steam. If the wash is not accepted, the diagnostic message PRISM WASH WARNING will appear. If no wash is accepted during wash tolerance time, the message becomes PRISM WASH FAILURE. Both messages and the wash tolerance counter are reset by a successful wash. The Wash check mode, automatic wash cut differs from the standard mode by stopping the wash 2 seconds after the nD falls below the limit.

To stop the measurement for the duration of the prism wash, choose MEASUREMENT HOLD DURING WASH and in that menu activate the hold function. The CONC reading and mA output are held in the value they had immediately before starting the wash cycle. You can also stop temperature measurement for the duration of the wash by setting TEMPERATURE HOLD DURING WASH.

To set a low temperature limit, choose WASH INHIBIT TEMPERATURE ENABLE, enable it (factory setting is disabled) and then set the temperature with WASH INHIBIT TEMP VALUE. The temperature is in the units that is chosen from the Calibration menu as the secondary unit.

The empty pipe check prevents washing if message is NO SAMPLE, meaning that there’s no process liquid in the pipe. To deactivate (or activate) the empty pipe check, choose EMPTY PIPE CHECK and then the appropriate menu command.

To change the wash nD limit, select WASH VERIFY ND LIMIT to set the nD to be used by the wash check functionality.

If you have set a wash verify delta nD limit, a temporary wash verify limit is calculated in the beginning of wash: nD limit = nD current – ΔnD. This temporary limit is compared to actual wash verify nD limit parameter, and the higher of these values takes precedence.

To set wash tolerance time, select WASH FAILURE TOLERANCE to set the time during which a wash has to be accepted. If no wash is accepted during wash tolerance time, the message becomes PRISM WASH FAILURE. The wash tolerance counter is reset by a successful wash.