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rasky1000
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Join Date: Mar 2013
Posts: 2

Siemens Pressure Transmitter

03/14/2013 2:59 PM

What can be wrong, Need urgent help.

I have a siemens pressure transmitter installed on my cyclone but currently it reading is not consistent for example it read 70kpa for about 12 hrs and start decreasing to a lower value and will trip the Mill discharge pump via ball and sag mill. It has been doing that for couple of day now, have ordered for new one from siemens but the lead time is 6 wks. What can be the problem with my transmitter? Any help please.,
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lyn
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Join Date: Oct 2008
Posts: 42355
Good Answers: 1693
#1

Re: Need urgent help.

03/14/2013 3:07 PM

Sounds like a blockage. Maybe a bad PT.

I can't see anything from here, so that's about it.

What does Siemens say to do to check the PT.

Did you look at their trouble shooting guide on the web, read the manual you got with the instrument?

Call them and ask for help?

PWSlack may offer some advice, if he sees this.
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SolarEagle
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Join Date: Mar 2007
Location: by the beach in Florida
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#2

Re: Siemens Pressure Transmitter

03/14/2013 3:35 PM

You might do a little troubleshooting, I found a manual....

http://www.lesman.com/unleashd/catalog/transmit/Siemens-SITRANS-P-DSIII/sitransp_dsIII_man.pdf

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lyn
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Join Date: Oct 2008
Posts: 42355
Good Answers: 1693
#3
In reply to #2

Re: Siemens Pressure Transmitter

03/14/2013 3:40 PM

I doubt that OP will try to open it, but if he does, I couldn't make the link work.

The OP also needs someone to trouble shoot a breaker for him.
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Iris
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Join Date: Jul 2010
Posts: 669
Good Answers: 176
#4

Re: Siemens Pressure Transmitter

03/14/2013 5:50 PM

I can load the manual from that link. Troubleshooting is on pages 137-139.

Do you have a mechanical pressure gauge tapped off the same point to compare with?

How do you know that the transmitter is not giving a proper reading?

Most Siemens DSIII's have a digital indicator (may be under the screw cover). Does the indicated pressure correspond with the analog output?

If it is truly an improper reading, there's little you can do if it is a faulty transmitter.

Other factors that can cause decreasing indicated pressure readings are
- leakage in the impulse tubing/piping (not uncommon, leakage can change with heat or vibration)
- blockage that bleeds out on the transmitter side of the blockage decreasing the indicated pressure (I've only seen it once in 30 years)
- a root valve or isolation valve is leaking to the vent port.
- on a DP, the high side vent plug is bleeding/leaking
- on a DP, the equalizing valve on a 3 valve manifold leaks (very common)
- DC power supply has sufficient voltage to power the transmitter but insufficient voltage to drive the 4-20mA current output at the higher indicated pressure.
- faulty transmitter

70 kPa is 10psi, well within a range where a DP might be used for a gauge pressure reading, so that's why I included the DP comments.

If your transmitter is the 0-1bar range, then the maximum permissible pressure is only 6 bar. Could yours have been overpressured?

In the US, Siemens has a 5 year powered warranty on the DSIII's. There's a tamper proof clock built into the transmitter. If it's really a baddie, it might be under warranty.
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PWSlack
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United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
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#5

Re: Siemens Pressure Transmitter

03/15/2013 4:44 AM

Follow the advice above. There is little to be added, apart from, why are there no spares at the facility that would take the sting out of a six-week lead time? Is this instrument on a planned preventative maintenance schedule owing to its perceived criticality to the process?

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Iris
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Join Date: Jul 2010
Posts: 669
Good Answers: 176
#6

Re: Siemens Pressure Transmitter

03/15/2013 1:56 PM

A comment about replacing a field instrument (driven by mention of the 6 week delivery)

Field instruments have multiple character part numbers, with fields for things like factory configuration or whether a mounting bracket is carbon or stainless steel, or which hazardous area classification it carries.

When you order a replacement, it warrants understanding exactly what you're ordering, because there's no reason to pay any option you don't need or use, like paying for another optional mounting bracket.

Just because a particular field instrument is installed in a given service doesn't mean that it's optimal for that service. In my 30 years, I've run across both tons of unused and therefore useless options and the opposite - options that should have been installed but weren't, like a local indicator or vent plugs.

6 week delivery for a pressure transmitter indicates either some non-standard wetted material or some option that forces delivery from an overseas location. If you really need a substitute pressure transmitter in less time, it might be worth shopping for one. Siemens does not allows its US reps to stock product, a 1950's business model, but other brands do let their distributors stock or can make better deliveries than 6 weeks happen, again depending on what's required
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Iris (2); lyn (2); PWSlack (1); SolarEagle (1)

Previous in Forum: Class A & B in Temperature Sensor (PT 100 & PT 1000)   Next in Forum: Extemely Low Pressure Regulator

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