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Installation and Configuration Manual 51
General Maintenance
Calibration Check General MaintenanceUsing 795X Processing Electronics
Error on indicated density
If the indicated density is in error, follow the table below and, if necessary, refer to the other tables
later in the chapter to find the cause of the fault.
Table 7-1 Error checking for viscosity
What to check: What to look for: What to check next:
Indicated viscosity Reading unsteady
(more than ±5 cP)
• Time periods τ
A
& τ
B
(below).
• Is the viscosity signal input 0 V connection (PL2 pin2)
connected to 0V on the Signal Converter (PL1 pin 4)?
• If the readings are still unsteady, the installation is probably
the cause of the fault (see Section 7.3.3 below).
Reading out of limits •Do the calibration coefficients programmed into the Signal
Converter match those on your factory calibration certificate?
• Does the value of Q match that inferred from the table of set
viscosities shown on your factory calibration certificate?
• Is the viscosity more than the “viscosity high limit” value? -
SET limit value to "1.00E+99" to find out.
• Is the viscosity less than the “low viscosity limit” value? - SET
limit value to "-1.00E+99" to find out.
• Has the fluid viscosity actually changed to the value shown?
Compare a sample measured with a known viscosity
standard with the 7827 meter.
• Product build-up on tines (see Section 7.3.3 below).
• Corrosion or erosion on the tines (see Section 7.3.3 below).
• Non-Newtonian fluid. Contact Micro Motion.
Reading not updating • Is the viscosity value FREE on the Signal Converter?
• Are both time period values FREE in the Signal Converter?
(Below)
• Is the viscosity more than the “viscosity high limit” value? -
SET limit value to "1.00E+99" to find out.
• Is the viscosity less than the “low viscosity limit” value? - SET
limit value to "-1.00E+99" to find out.
• Check connections between 7950/1 and 7827 meter (below).
• Meter not powered correctly: Check consumption at the
meter (below).
• Fault with 7950/1: Refer to the 7950/1 Handbook, then
contact Micro Motion if fault persists.