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Rosemount Opacity Analyzer Problems & Solutions

Installing 40F0050R02 (RIGAS single element LCW) or 4848B50G02 (Rosemount single element shutter)

There are only two significant things to consider when installing LCW#1 in the OPM2000, OPM2000A, OPM2000R, or OPM2001: [1] over-tightening and [2] stand-offs.

When attaching the LCW to the transceiver’s mounting block, don’t over-torque or over-tighten the four (4) hold down screws. We always recommend “finger tight plus a skosh” (meaning finger tight plus just a tad (smidgen) more). The stack-up is normally in this order: aperture plate – stand-off – o’ring – backing plate (large holed) – LCW – top plate (small hole) – o’ring – screw head. An alternate stack-up can be in this order: aperture plate – stand-off – LCW – top plate (small hole) – o’ring – screw head.

The stand-offs are a factory modification and VERY important to the life span of the LCW. By putting the LCW 3/4″ away from the aperature plate, the beam has a chance to disperse and thus more of the actual LCW active surface area is utilized. This helps prevent “burning” the center out of the LCW (see picture). This is very critical in the OPM2001 as its high intensity beam from the 20 watt halogen lamp will cure the filler material and damage the LC event sites.

Stand-offs promote stability too because more liquid crystal event sites are being utilized if the beam is allowed to spread; as the LCW ages, LC sites tend to lock either open or closed, so if the beam is relying on 1000 events sites instead of 1,000,000 event sites, it will ‘seem” to become unstable sooner as event sites fail due to normal aging.

Parts:

LCW#1: 40F0050R02

 

LCW holding screws: 4-40 socket head, black anodized screws typically

Stand-offs:  4-40, 3/4″, aluminum, hex barrel, male-female

(LC stands for liquid crystal)

 

 

 

 

 

 

 

A LCW#1 "burned" by a high intensity light source

 

 

OPM2000, OPM2000A reading 105%

Background: The 105% indication and reading is Rosemount’s way of showing an error message; it was presumed that everyone in the opacity business would recognize that there is no such thing as 105% opacity and that it would instantly mean ‘analyzer failure’ to anyone observing it on the monitor’s display. It was also an easy way to get the milliamp output signal to rail high at about 21 maDC.

Components affected: LCW (liquid crystal window), lamp (bulb), power supply (SLB, Stack LON Board), G-64 LON Board, interconnecting cabling, & temperature.

The fault alarm (105% opacity) can come from any of the following:

  1. failing bulb/lamp or lamp power supply
  2. failing LCWs or LCW power supply
  • – VLTH [volts too high]
  • – LMPF [lamp failure per software algorithm]
  1. loss of Eshelon communications (LON)
  2. failing wire harness (to lamp or LON communications)
  3. failed calibration
  4. corrupted software on the Stack LON Board
  5. failing detector board (±15 vdc power comes from the SLB)

But not:

  1. actual stack opacity conditions (high opacity)
  2. misalignment
  3. dust on barrier window and/or corner cube
  4.  steam that has changed phase to vapor

Call us to help you diagnose this. Please provide the following:

  • model number
  • age of LCWs
  • age of bulb/lamp
  • reference voltages (8) (under Cal, Reference Voltages)
  • current ‘run’ voltages (4) (under Data, Volts)
  • temperature

High Opacity Readings on Rosemount OPM2000, OPM2000A, OPM2000R, OPM2001

Components affected: LCW, liquid crystal window, lamp, barrier window, alignment, bulb, & temperature.

High opacity can come from any of the following:

  1. actual stack opacity conditions
  2. misalignment
  3. failing bulb/lamp or lamp power supply
  4. failing LCWs or LCW power supply
  5. dust on barrier window and/or corner cube
  6. steam that has changed phase to vapor

Call us to help you diagnose this.

Please provide the following:

  • model number
  • age of LCWs
  • age of bulb/lamp
  • reference voltages (8)
  • current ‘run’ voltages (4)
  • temperature

Communications Failure on Rosemount OPM2000 (original)

Communication failures typically fall in to 2 categories:

  1. bad interconnecting wiring
  2. board faults

If you’re not using Belden 8162 or 8163, you run the risk of causing a communications problem that gets worse with time.

The CRU talks RS232 which then routes to a converter (RS232 to RS422) before the signal leaves the CRU. The transceiver receives the RS422 directly without a converter.

Here is the order of typical failures:

  1. RS232/RS422 converter in the CRU
  2. IO Plexor
  3. CPU board in the CRU

Call for more details.

Communications Failure on Rosemount OPM2000A, OPM2000R, OPM2001

Communication failures typically fall in to 2 categories:

  1. bad interconnecting wiring
  2. board faults

If you’re not using Belden 8162 or 8163, you run the risk of causing a communications problem that gets worse with time.

The LON originates on the Stack LON board AND the IG-1 serial gateway. If either board is faulted, unpowered, corrupted, blown power supply,  or whatever then you’ll get COMM FAULTS.

Call for more details.