Calibration of Inbuilt Measuring Devices

[eternal_atlas]

In our project called Operation and Maintenance of water pumping and lifting stations, we have to monitor the effective function of pumps and water flow through some measuring devices in the control panel.

Here is my Question?

" Whether the devices like Pressure Guage,Thermometer,Flowmeter has to be calibrated or not however the readings are taken as a daily report for decision making"?

" How we can ensure the data/readings taken by the operator is free from instrumental error even though it is inbuilt"?

" If it is not to be calibrated, Please tell me why and how"

" If it is to be calibrated, Please tell me why and how"

 

[joshua_sx1]

…if you are basing your decision (specifically a major one) from your factual data being taken from your measuring devices, you’ll have to calibrate them for your own good… whether it is a requirement or not…

…how to calibrate them?... coordinate with your supplier or the one who built that control panel…

 

[Umang Vidyarthi]

In our project called Operation and Maintenance of water pumping and lifting stations, we have to monitor the effective function of pumps and water flow through some measuring devices in the control panel.

Here is my Question?

" Whether the devices like Pressure Guage,Thermometer,Flowmeter has to be calibrated or not however the readings are taken as a daily report for decision making"?

" How we can ensure the data/readings taken by the operator is free from instrumental error even though it is inbuilt"?

" If it is not to be calibrated, Please tell me why and how"

" If it is to be calibrated, Please tell me why and how"

Since your daily decision making depends on these guages & meters, IMO it is mandatory for you to have them calibrated, the frequency of which depends upon usage and the environmental conditions, and/or as per advise of the manufacturer.

Your supplier is supposed to issue calibration certificate for the in-built instruments, if not, you obtain from them. Calibration alone can ensure that the readings are free from instrumental error.

You may contact the calibration labs in your area for 'Calibration' or seek guidance from manufacturer/supplier.

Hope this helps

Umang

 

[Hershal]

Moved as the question is a calibration specific question, and may attain more answers in the 17025 forum.

 

[AndyN]

Let me offer a word of caution regarding suppliers of measuring equipment or test and inspection/process control panels:

They don't necessarily know any more about calibration than you do! I have encountered many situations were even equipment used for safety related checks were not calibrated and even the manufacturer said 'It's self calibrating"!!

So, certainly the equipment used to take readings from could be calibrated or at least verified against a calibrated and similar device. Often, in this type of control panel, the built in device may have a 'tee' in the feed line so that another measuring device may be attached. If it has, use a master flow meter or pressure gauge to verify the indicator in the control panel.

We need to know a bit more about what's being recorded - is it a range of flows over time or a minimum flow? That would make a difference to what calibrations are performed.

 

[Umang Vidyarthi]

Since your daily decision making depends on these guages & meters, IMO it is mandatory for you to have them calibrated, the frequency of which depends upon usage and the environmental conditions, and/or as per advise of the manufacturer.

Your supplier is supposed to issue calibration certificate for the in-built instruments, if not, you obtain from them. Calibration alone can ensure that the readings are free from instrumental error.

You may contact the calibration labs in your area for 'Calibration' or seek guidance from manufacturer/supplier.

Hope this helps

Umang

I am at fault for using the words that 'supplier is supposed to issue...'.Please read it as :'Supplier is supposed to give you the calibration certificate, issued by the manufacturer....'

Sorry for miscommunication.

Let me offer a word of caution regarding suppliers of measuring equipment or test and inspection/process control panels:

They don't necessarily know any more about calibration than you do! I have encountered many situations were even equipment used for safety related checks were not calibrated and even the manufacturer said 'It's self calibrating"!!

So, certainly the equipment used to take readings from could be calibrated or at least verified against a calibrated and similar device. Often, in this type of control panel, the built in device may have a 'tee' in the feed line so that another measuring device may be attached. If it has, use a master flow meter or pressure gauge to verify the indicator in the control panel.

We need to know a bit more about what's being recorded - is it a range of flows over time or a minimum flow? That would make a difference to what calibrations are performed.

You are absolutely right Andy, a vast majority of suppliers have no inkling about calibration cert or of its importance. For most of them, the cert is just another piece of 'paper' to be handed over to the customer. Secondly if the device in question has spent too long a time at supplier's shelf (beg your pardon-how long is too long is debatable), and the environment conditions have an effect on the instrument, then it calls for second calibration.

Umang

 

[Ajit Basrur]

............. Here is my Question?

" Whether the devices like Pressure Guage,Thermometer,Flowmeter has to be calibrated or not however the readings are taken as a daily report for decision making"?

" How we can ensure the data/readings taken by the operator is free from instrumental error even though it is inbuilt"?

" If it is not to be calibrated, Please tell me why and how"

" If it is to be calibrated, Please tell me why and how"

Having built-in gages is a common thing for water systems. Get in touch with the supplier and he can do calibration for you.

Additionally, you can refer Calibration Guidelines for Water Distribution System Modeling issued by the American Water Works Association for more details.

 

[Ajit Basrur]

Another one is Water Distribution System Analysis - A Reference Guide for Utilities that is issued by United States EPA (Environmental Protection Agency) and has scetions on calibration.

Sorry I havent gone through it

 

[BradM]

This is a good question by the OP. I would also refer to re-read of Andy's post above; especially about mfg. recommendations and specifications. They are primarily in the business of making stuff; not in the metrology business.

1. Make a list of some kind of all the instruments involved with the equipment. Typically, pressure gauges don't have serial numbers, so you would want to assign a unique tool number.

2. Determine in the system which gauges are recorded, affect quality, etc. There will be some gauges that need to be calibrated, and some that don't. Make sure (whatever system that you have in-house) that the non-calibrated instruments are not used. Many times I could walk into a facility and talk with the person that operated the equipment. They were quite accurate in knowing which instruments needed to be adjusted. Amazingly, they could tell which instruments were fine, and which ones were way off.

3. The gauges that need to be calibrated can be calibrated in-place or rotated. Saying, you could buy a backup set of instruments for the calibrated instruments and rotate them out whenever you have a calibration cycle coming up. NOTE: If the calibration turn around time is longer than you calibration cycle, you may have to buy an additional set.

4. Calibrate in-place may involve shutting the system down, or like Andy alluded to, having ports where instruments can be verified in-line. I would much rather identify a point where the instrument can be removed and checked across its use range, but hey, you take what you can get.

Now, you may have a system where you have devices that operate another device. For example, you may have a flow switch that turns a pump off if the flow gets too low (where the pump does not burn up). In that instant, I would probably check the flow switch. Other time, a flow switch may turn on a second pump if demand increases; you may decide that does not need to be checked.

Just as a suggestion... it may be worthwhile to bring someone in for at least the first calibration. While I would rely on competent calibration sources primarily, it may be worthwhile to hire a systems integrator that specializes in automating lift stations. They might can recommend for that system what is important, and the best approach to calibrating the instruments.