Troubleshooting

Hydramotion viscometers are designed for long service with minimal maintenance. Use of resilient materials and a solid-state design allows long-term use while maintaining factory calibration and accuracy. Should a problem occur, the VP550 offers a number of facilities to help trace the cause.

5.1 CON alarm

If the alarm indicator LED  shows red and the alert message “con” is shown in the top right-hand corner (Figure 23), an expected input is either not present or (in the case of a 4-20mA input) below the 4mA threshold.

• In this case:
  (1) Check all input settings and all input connections to the VP550.
  (2) If the transducer has no integral PRT, verify that the transducer temperature source is set to OFF (see Section 3.2.1).

5.2 SIG alarm

• If the alarm indicator LED shows red and the alert message “sig” is shown in the top right-hand corner (Figure 24), the VP550 cannot detect a signal from the transducer.
• In this situation, the 4-20mA analogue output signal will fall to 1mA (“failure mode”).

• In this case:
  (1) Check all electrical connections from the viscometer to the VP550.
  (2) Check the integrity of all connecting cables.
  (3) Check that the transducer is receiving power.

5.3 Unexpected or erratic readings

• If unexpected or erratic readings are obtained and/or damage is suspected:
  (1) Withdraw the viscometer from the fluid.
  (2) Clean and dry the sensor.
  (3) Press for some seconds until the SETUP menu appears. Select
  DIAGNOSTICS and press . The following list will appear:

(4) Select TRANSDUCER RAW and press . Note the values of the following parameters:

when the transducer is
(a) clean, dry and in air (not in contact with any fluid or surface), and
(b) immersed in water at about 20°C.

(5) Contact Hydramotion Service & Repair:
email      service@hydramotion.com
phone    +44 (0)1653 600294
fax          +44 (0)1653 693446

• When reporting the fault, please provide the following information:

(1) Background to the problem:

(a) Transducer serial number

(b) How long the viscometer has been in service

(c)The fluid being measured

(d) Measurement conditions (temperature, pressure, flow rate)

(e) Current fluid viscosity and temperature

(f) Expected viscosity

(g) Stability of the measurement

(h) How long the viscometer had performed correctly before the apparent fault was observed.

(2) The noted values of L and F.

• The serial number of the transducer is stamped on the label affixed to the enclosure. The serial number can also be verified by navigating to SETUP > DIAGNOSTICS > TRANSDUCER ID.

5.4 Temperature display incorrect or missing

• If the VP550 has a temperature input but temperature and/or temperature-corrected viscosity is not  shown on the display, verify that the transducer and VP550 temperature inputs are both set to VP I/P.
• If the transducer has an integral temperature sensor, verify that both the transducer and VP550 input settings are correct (Sections 3.2.1 and 3.3.3).

5.5 Other (internal) alarms

• If the message “alm” is shown in the top right-hand corner, there is an internal alarm condition (Figure 25).
• On power-up, the active alarm(s) will appear automatically if there is an alarm condition. To revert to the Main Display, press the left arrow .
• To see the alarm message(s), either
  (1) with the Main Display showing, press , or
  (2) navigate to SETUP > DIAGNOSTICS > SYSTEM ALARMS.
• Alarm messages are:

alarm	significance	action
< TD RESTART >	power-up indicator	if persistent, contact Hydramotion
< TD E2 FAIL >	non-volatile memory failure	contact Hydramotion
< TD F2 READ >	frequency data failure
< TD F3 READ >	frequency data failure
< TD PRT READ >	no data from transducer PRT
< TD PRT DATA >	transducer PRT data invalid
< TD CALCS >	viscosity data invalid
< VP RESTART >	power-up indicator	if persistent, press . If still persistent, contact Hydramotion
< VP E2 FAIL >	non-volatile memory failure	contact Hydramotion
< TD TELEMETRY >	no data from transducer	check connections. If OK, call Hydramotion
< VP PRT READ >	no data from external PRT	contact Hydramotion
< VP PRT DATA >	external PRT data invalid
< VP PCF CALC >	PCF calculation error
< VP ADC TEMP >	4-20mA temperature input error
< VP ADC DENS >	density input error
< VP ADC PRESS >	pressure input error
< VP POWER >	power supply outside specified limits	check power supply voltage/current. If OK, call Hydramotion
< VP PV LOW >	relay alarm: viscosity below LO-LIM	check process
< VP PV HIGH >	relay alarm: viscosity exceeds HI-LIM

5.6 Serial communications

• The VP550 will normally adopt the correct Modbus® transmission mode (ASCII or RTU) automatically. If necessary, however, the mode can be set by navigating to SETUP > VP SETUP > SERIAL SETTINGS > Mode.
• Serial communications between the VP550 and a host computer may be monitored by navigating to SETUP > DIAGNOSTICS > VP TELEMETRY:

• To view or modify the address of the VP550, navigate to SETUP > VP SETUP > SERIAL SETTINGS > ADDR.
• Serial communications between the the VP550 and the transducer may be monitored by navigating to SETUP > DIAGNOSTICS > TRANSDUCER TELEM:

• To view or modify the address of the transducer, navigate to SETUP > TRANSDUCER SETUP > SERIAL SETTINGS > ADDR.

5.7 USB link

• The USB link between the VP550 and a host computer may be monitored by navigating to SETUP > DIAGNOSTICS > USB TELEMETRY:

• To view or modify the address of the VP550, navigate to SETUP VP SETUP USB SETTINGS ADDR.