belt weigh scale comments

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EXCEL CONSULTING ENGINEERS PVT. LTD.No. 72, Kasi Estates, Ashok Nagar, Chennai – 600 083. Tel : 474 5586; Tele Fax : 474 4000

E mail : [email protected]

Ref.: XL/FIL/989/673 18th December 2000

M/s. Fenner (India) LimitedNo.82, Peters RoadChennai – 600 014. Fax No.: 8265462

Kind Attn.: Mr. S. Subbaraj / Mr. ManikandanDGM – Engg.

Dear Sir,

Sub : Bagasse Handling System – Godavari Sugars – Drawing Review for Belt Weigh ScaleVendor – IPA Pvt. Ltd.

Please find enclosed a draft letter along with enclosure enumerating the comments on thedrawing submitted by M/s IPA Ltd.

The drawing has been reviewed based on the specification that we had sent to you for procuring the belt weigh scale.

We find that the drawing lacks clarity and hence please forward the comments to thevendor for revising the drawing taking into account, our specification for belt weigh scaleand submit all the technical documents as asked for.

Thanking you and assuring you of our best services at all times,

Very truly yours,for EXCEL CONSULTING ENGINEERS PVT. LTD.,

-sd-

S RENGARAJANDirector

Encl. As above

mailto:[email protected]

mailto:[email protected]



18-12-2000

DRAFT LETTER

To : IPA PVT. LTD.

Kind Attn :

Dear Sir,

Sub.: Bagasse Handling System for 24 MW CPP - Godavari Sugar Mills Ltd. – BeltWeigh Scale Drawing Review

Please find enclosed our comments on the drawings submitted by you. Please incorporatethese comments and resubmit your drawings along with the technical data asked for. Also,please fill in the data sheet, which we had attached with our enquiry specification.

Thanking you,

Very truly yours,for FENNER INDIA Ltd.,

Encl. As above



COMMENTS ON BELT WEIGH SCALE DRAWING

1. Mention the capacity of belt weigh scale on the specification sheet.

2. Furnish further detailed drawing of load cell showing its enclosure details like, IPclass / dimensions, terminal details showing the load cell O/P signal, load cell excitationall wired through terminal blocks. Elaborate on load cell excitation circuit. Also furnish

write-up on load cell operation, its interaction with ADC card, etc. (please note that as per spec. cl.1.0 load cell shall be in IP67 enclosure).

3. In specification for belt scale under title “load cell “, our comments are as follows:

a. Mention the accuracy of load cell. Please note that as per cl.1.0, “General” of our

specification for belt weigh scale, the accuracy of overall system shall be ± 5% or

better.b. You have mentioned against “Input range” as + / - 16mVDC. Please indicate in the

detailed drawing of load cell from where this input is derived.c. Add a note on the maximum / minimum weight range that the load cell can

measure accurately (i.e., accuracy as you are going to indicate in the spec.)

d. You have mentioned excitation 4 wire system + /- 5V DC, 120mA in the specificationsheet for load cell and your drawing No. G/ES/3/2K/1485 Rev.0, “Schematic Diagramfor Belt Scale” indicates from a block in ADC card titled, “Load cell excitation circuit”and output is marked as “Excitation”. Is this the excitation to load cell, which youare indicating in the specification sheet as “Excitation 4 wire system, + / - 5VDC 120mA.If that is so then please clarify the following :1. Why 4 wire is required?2. Why this cable is not indicated in the drawing G/ES/3/2K/1483, Rev.1, titled

“Terminal Block Details for Belt Scale”. Please furnish a detailed terminal blockdetails for all the following sub-components of weigh scale, like load cell, speedsensor, electronic console, flow rate indicators, totaliser (both local and remote), junction box, etc. Please note that all interconnecting cables between the sub-components constituting belt weigh scale system shall be in your scope. Pleaseconfirm and furnish these details of cables supplied by you in the drawings.

e. Please indicate in the drawings how you are protecting the load cells againstoverloading, vibration.

f. Please confirm that the accuracy of load cells / transducers shall not be affected byi. Variation of belt speedii. Belt tension overloadiii. Vibrationiv. Noisev. Temperature variation

vi. Electrical disturbancesvii. Belt swayviii. Non-uniform loading of material on belt.Please elaborate by furnishing a detailed write-up.

4. Further, as a part of procedural checking and records, please furnish the following

documents :a. Instrument panel wiring diagramb. Hook-up diagramc. Erection / installation diagrams for all primary sensors and field mounted equipmentd. Loop schematic diagrame. Instrumentation layout drawing showing location of sensors, transmitters, etc.

5. Furnish list of 3 years spare and commissioning spares.



6. Provide technical details of all equipment of weigh scale, indicating bridge impedance,mv/v output, hysterisis, linearity, overload limit (safe and ultimate, etc., as per cl.3.1 of specification and a detailed technical literature of each instrumentation equipmentoffered, approximate instrument panel dimensions / total power required for instrumentation. Also, please refer clause 3.2 “Drawings / Documents to be submitted” andsubmit the same.

7. Indicate to what standards IS / other international standards to which you equipmentcater’s (refer clause 2.0 and confirm to cater to the IS mentioned).

8. We find calibration unit missing in block diagram G/FS/3/2K/1485. Please include.

9. Please indicate the cable entry sizes in ET clearly. Mark in each equipment the cableentry meant for users and your interconnection distinctly. Please note that we requirea 1” ET hole exclusively for PLC connection cable and 1” ET for power supply cable(since PLC interrogation voltage is 24V DC and power supply that will be arranged byus is 230VAC).

10. Please note that we will provide you with 1No. 230V AC power supply to your power supply card in drawing G/ES/3/2K/1485. All other power supplies required by your system shall be derived by you and all such interconnection shall be through differententry other than t hat of the user’s cable entry provided.

11. Please clarify the system voltage for totaliser pulse OUT. Since this is shown as +, -,we understand it is an analog signal. If this is different from 24VDC, a separate cablewould be needed for O/L & U/L contact wiring. Please note that the distance betweenbelt weigh scale at site and the remote indicator at control room is around 125 mtrs.Please confirm that the belt weigh scale equipment shall be suitable to transmit thisoutput to the remote indicator situated at a distance of 125 mtrs.

12. Provide earthing terminals for all cabinets and indicate the same in your drawings.

13. Enclosures shall be IP67 for load cell and IP65 for BWS panel, as per spec. Pleaseconfirm.

14. In our specification clause 1.0, we have asked for flow rate indicator and digitaltotaliser with battery back-up for belt weigh scale, both for local panel and remotepanel mounted instruments (cl.1.0) where as we find, neither your drawing nor thespecification has included the same. Please confirm to include the same in your revised drawing.

15. All enclosures shall be of minimum 2mm thick CRCA sheet, please confirm.