PD w data attch.pdf

09M-273A-MA

12 August 2008

Directorate of Metrology Purchase Description

200G Balance

1.0 Scope:

This purchase description specifies a 200g Analytical Balance to be used in the calibration of mass standards.

2.0 Salient Characteristics:

The 200G Balance will incorporate the following characteristics, which are essential to the government.

2.1 Measurement Range:

The 200G Balance will have a continuous range of 0 to 210 grams minimum.

2.2 Resolution:

The 200G Balance will be readable to 0.01 milligrams throughout the measurement range.

2.3 Full Range Performance Specifications:

2.3.1 Repeatability

The repeatability of the instrument shall be +/- 0.02 milligrams or better at a load of 10 g and +/- 0.03 milligrams or better at a load of200 grams. At any load point throughout the measurement range the repeatability shall be no worse than 0.03 milligrams.

2.3.2 Linearity:

The 200G Balance will have a full range linearity of +/- 0.1 milligrams or better.

2.3.3 Direct Readout Accuracy:

The 200G Balance will have a full range direct readout accuracy of +/- 0.5 milligrams or better throughout the measurement range.

2.4 Overload Protection:

The 200G Balance will be capable of withstanding a load of500 grams (250% of Full Scale) with no damage to the instrument.

2.5 Settling Time:

When operated under stable environmental conditions, the 200G Balance shall have a typical settling time of 10 seconds or less.

2.6 Eccentricity:

The 200G Balance will have an eccentricity tolerance of +/- 0.2 milligrams or better at any load throughout the measurement range.

2.7 Draft Shield:

The 200G Balance will have a draft shield to minimize the effects of air currents upon the measurement.

2.8 Automatic/Manual Balance Adjustment:

The 200G Balance will have a built in internal weight to be used to accomplish automatic adjustment of the balance. This automatic adjustment will be accomplished when triggered by changing environmental conditions and/or additionally at intervals selected by the user. In addition the 200G Balance will be capable of adjustment by means of a user supplied external weight of known mass values. The user must be able to enter mass values for the external weights and must be able to edit the values for the internal weight in the event that the external calibration disagrees with the internal calibration.

2.9 Computer Interface:

The 200G Balance will have an RS 232C interface which allows a PC to be connected to the balance and data to be collected by the Pc.

2.10 Power:

The 200G Balance will be capable of operating on standard 110 V AC 60 Hz. +/- 10% electrical power.

2.11 Mechanical and Physical Requirements:

2.11.1 Physical Footprint:

The 200G Balance shall fit in a volume of 300mm x 600mm x 500mm (W x D x H).

2.11.2 Commercial Parts:

Commercial parts and materials that are used shall have properties consistent with a precision laboratory instrument.

2.11.3 Design and Construction:

The equipment shall be designed and constructed of materials that meet the requirements of this specification and in accordance with the best commercial practices for industry approved equipment. It shall be designed and manufactured to maximize reliability, maintainability, accuracy of operation, and ease of operation. All parts such as shafts, bearings, regulators, switches, controls, etc ... , shall have proper clearance and adjustments. They shall work together so that the equipment will supply the rated requirements without unnecessary strains, vibrations or overheating. They shall be able to withstand the conditions met in shipping, storage, installation and service. All materials and parts of this equipment shall be capable of withstanding the environmental requirements of this specification.

2.11.4 Selected Components:

Matched and selected components shall be kept to an absolute minimum. Use of specially built, nonstandard components shall be avoided.

2.11.5 Environment:

2.11.5.1 Operating Temperature:

The 200G Balance shall be capable of operating in an ambient temperature of 65 to 80 degrees F without loss of required performance.

2.11.5.2 Operating Humidity:

The 200G Balance shall maintain specified performance in an atmosphere from 20% to 50% relative humidity.

3.0 Safety:

The safety of all personnel will be assured in the event of any incidental physical contact with the outside of the equipment and during the changing of the fuse with the power to the system and it's components on.

4.0 Testing:

This item will be inspected and accepted at destination as stated in the contract. The item will be checked with test equipment with parameters equal to or better than those required to assure that specified performance parameters are met. Test equipment used shall have first echelon certification directly traceable to the National Institute of Standards Technology (NIST) or other AFMETCAL approved sources where required. Tests will be performed to assure that the item meets the requirements of paragraphs 2.1 through 2.11 of this purchase description as stated in the contract. Such testing at destination does not relieve the contractor ofperforming all inspections and quality checks at the point of manufacture as necessary to assure performance as specified herein.

1. Attachments: Data Requirements

Attachment to

Purchase Description 09M-273A-MA

200 Gram Balance

DATA REQUIREMENTS

MANUALS: A complete user and service manual and calibration procedure shall be provided with each unit in contractor format. Manuals shall be on CD/DVD-ROM in Indexed Portable Document Format (iPDF). The manuals shall comply with Data Item Description (DID) DI TMSS-80527B and the Contract Data Requirements List (DD Form 1423).