Ref.. Table of Contents Page 1. Scope 2 2. Objective 2 3. Definitions 2 4. Responsibility 3 5. Procedure 3 6. Precautions 14 7. References 14 8. Appendices 14 9. Revision History 14 Original Authorised Copy for: Reading Copy Written by: Reviewed by: Approved by: Signature/Date: Signature/Date: Signature/Date: Page 1 of 16
Ref.. 1. Scope This Standard Operating Procedure (SOP) applies to the staff and students making use of the Precisa 1600C Precision Balance in the laboratories of the Pharmacy Department, University of Malta. 2. Objective To describe the procedure for the installation, configuration, operation, calibration, maintenance and troubleshooting of the Precisa 1600C Precision Balance. 3. Definitions 3.1. Adjustable Feet / Levelling Screws: Two circular screws situated at the bottom of the balance that are manipulated to level the balance out. 3.2. Calibration: A procedure performed to check a measuring instrument against an accurate standard to determine any deviations and correct for errors. 3.4. Configuration Parameters: A number of different options that are used to set the balance according to the user s preferences. 3.5. Floating Display: A function that enables the balance to adapt its integration time to the conditions of the environment. 3.6. Main Menu: Allows the user to adapt the balance to his/her changing requirements and to any peripheral conditions. It consists of 4 main options: Calibration to carry out the calibration process Program Second Unit of Mode Key to choose the unit to be set as Unit2 Floating Display to choose the desired time for the floating display, if being used, i.e. 0.08 seconds, 0.16 seconds or 0.32 seconds Stability Detector to choose the desired stability for the balance i.e. Low, Medium or High 3.7. Mode Key: Allows the user to call up functions which are activated once this key is released, such as result, time and date printouts as well as functions that affect the weighing mode such as switching from Page 2 of 16
Ref.. Unit1 to Unit2 or vice versa or else to change between percentage and counting mode. 3.8. On/Off Key: To switch the balance on or off. 3.9. T-Key: Used to tare the balance when this is in weighing mode. May also be used to enter configuration menu or main menu, to change from one parameter to the next in the individual sub-menus, to exit a menu and also to call up the calibration programme. 3.10. Tare: Allows the balance to display the weight of the sample only and not the combined weight of the sample and its container. 3.11. Unit1: The basic unit in which values are to be displayed in. This can be set as the gramme [g], grain [GN], penny weight [dwt], troy ounce [ozt], ounce [oz], pound [lb], carat [ct], metric carat [C.M.], Hong Kong tael [tlh], Malaysian tael [tlm] or Taiwan tael [tlt]. 3.12. Unit2: The secondary unit that can be programmed in the main menu. This can bet set as one of the units chosen for Unit1 with the addition of the count [PCS] or percent [%]. 3.13. Weighing pan: The area on top of which the material to be weighed is placed. 4. Responsibility 4.1. The members of the Department of Pharmacy (staff and students) are responsible for following this SOP. 4.2. The designated Laboratory Officer or Laboratory Assistant is responsible for ensuring that this SOP is followed. 5. Procedure 5.1. Installation 5.1.1. Place the balance on a stable surface, away from any vibrations. 5.1.2. Turn the adjustable feet/levelling screws at the bottom of the balance clockwise or anticlockwise until the air bubble in the spirit level is in the centre of the marked circle. Page 3 of 16
Ref.. 5.1.3. Insert power supply connector in the plug on the rear of the balance and plug the power supply into the mains supply. 5.1.4. Press the On/Off Key to activate the balance. 5.1.5. Wait until a stable 0,00 is displayed before use. 5.2. Configuration 5.2.1. Press and hold the T key whilst balance is still switched off. 5.2.2. Press the On/Off key while still pressing the T key. 5.2.3. Keep the T key pressed until the desired configuration parameter is displayed (see SOP/PD/304_01/A1). 5.2.4. Release the T key to access the desired configuration parameter. 5.2.5. Press the T key briefly but continuously until the desired function in the configuration parameter is displayed. 5.2.6. Press and hold the T key again to return to main menu. If this is not pressed for some time, the configuration menu will be abandoned automatically, and the standard configuration stored. 5.3. Using the Main Menu 5.3.1. Press and hold the T key until the desired option is displayed. 5.3.2. Release the T key to enter the desired sub-menu. 5.3.3. Press the T key briefly but continuously until the desired parameter in the sub-menu is displayed. 5.3.4. Press and hold the T key to return to the main menu. If this is not pressed for some time, the main menu is automatically abandoned and the balance enters weighing mode once again. 5.4. Weighing Mode 5.4.1. Ensure that the desired weighing unit is displayed. If this is not so, press the MODE key until it is displayed if it had been previously set as the basic unit i.e. Unit1 or as the secondary unit i.e. Unit2. 5.4.2. Place sample onto the weighing pan and read off value. 5.4.3. If using the tare function, place empty weighing container on the weighing pan, press the T key and then place the sample in the weighing container and read of the tared value from the display. Page 4 of 16
Ref.. 5.4.4. Use the tare function repeatedly if necessary. 5.5. Using the Mode Key 5.5.1. Counting Mode 5.5.1.1. Ensure that PCS was previously set as Unit2 from the main menu. 5.5.1.2. Place the number of pieces that are required as reference weight on the weighing pan. 5.5.1.3. Press and hold the MODE key until [Unit2 PCS] is displayed. 5.5.1.4. Release the MODE key to select the reference weight as the selected number of pieces and also to switch automatically to Unit2 i.e counting mode. 5.5.1.5. Remove the number of pieces used to set the reference weight. 5.5.1.6. Place the weight that needs to be counted and read the number of pieces from the display. 5.5.2. Percentage Mode 5.6. Calibration 5.5.2.1. Ensure that % was previously set as Unit2 from the main menu. 5.5.2.2. Place the reference weight on the weighing pan. 5.5.2.3. Press and hold the MODE key until [ref 100%] is displayed. 5.5.2.4. Release the MODE key to set the reference weight as the selected percentage and also to switch automatically to Unit2 i.e percentage mode. 5.5.2.5. Remove the reference weight used to programme the percentage function. 5.5.2.6. Place the desired sample and read the percentage of the reference weight from the display. 5.6.1. Allow a warm up time of about 10 minutes after switching the balance on. 5.6.2. Press and hold the T key until [CAL] is displayed Page 5 of 16
Ref.. 5.6.3. Ensure that there is nothing present on the weighing pan. If pan is not empty, and/or the balance is active, the digital display [--0000g] will continue to flash. 5.6.4. Allow [0000g] to be displayed to indicate that zero point measurement has been carried out. 5.6.5. Wait until balance display flashes [--1000g] and then place the recommended calibration weight (1000g) on the centre of the pan. 5.6.6. Wait until display shows [1000g] to indicate that calibration is finished and balance returns to weighing mode 5.7. Maintenance 5.7.1. Disconnect balance from its power supply before attempting to clean and leave it in its normal operating position. 5.7.2. Use a clean fine brush to remove any surrounding powder. 5.7.3. Use a moistened cloth with a mild cleaning agent to clean and remove any spilt material. 5.7.4. Ensure that the air bubble in the spirit level on the front end of the scale is in the centre of the marked circle. 5.8. Troubleshooting Fault Possible Cause - Balance not switched on correctly Display does not light up - Balance not connected to mains - Power failure - Faulty microfuse OL is displayed - Weighing limit has been exceeded UL is displayed - Weighing pan and/or pan support has not been assembled - Draught/ air currents present Weighing display changes continuously - Vibrations on table/floor - Weighing pan touching foreign body - Balance not tared Result seemingly incorrect - Balance not levelled - Outdated calibration - Strong temperature fluctuations - Location of balance is undesirable Display flashes continuously during - Calibration weight is too imprecise or calibration does not correspond to the recommended one Page 6 of 16
Ref.. 5.9. Flow Charts 5.9.1. Installation Start Place on stable surface, away from any vibrations Turn adjustable feet until air bubble in spirit level is in the centre of the marked circle Insert power supply connector in the plug on rear of balance and plug power supply into mains supply Press On/Off Key to activate balance Wait until a stable 0,00 is displayed before use End Page 7 of 16
Ref.. 5.9.2. Configuration Start Press and hold T key whilst balance is still switched off Press On/Off key while still pressing the T key Desired configuration parameter displayed Keep T key pressed until desired menu is reached Release T key to access desired configuration parameter Press T key briefly but continuously until desired function is displayed Save changes made Do not press any keys and allow balance to automatically return to weighing mode Press and hold the T key to save and return to main menu End Page 8 of 16
Ref.. 5.9.3. Using the Main Menu Start Press and hold T key Desired option displayed Keep T key pressed until desired parameter is reached Release T key to enter its submenu Press T key briefly but continuously until desired parameter is reached Save changes made Do not press any keys and allow balance to automatically return to weighing mode Parameter saved and returns to main menu End Page 9 of 16
Ref.. 5.9.4. Weighing Mode Start Desired weighing unit display Desired weighing unit previously set as Unit1 orunit2 Press On/Off key to switch off balance 1 Using tare function Place sample and container onto weighing pan Press and hold MODE key Press and hold T key and simultaneously press the On/Off key again Place empty weighing container on balance Read off value from the display Release MODE key when [Unit1 x*] or [Unit2 x*] is being displayed 1 Release T key when [Unit1] is displayed Briefly but continuously press T key until [Unit1 x*] is displayed Press T key Place sample in weighing container Keep using tare function repeatedly if necessary Press and hold T key to save and return to main menu Allow balance to enter weighing mode Press and hold MODE key until [Unit1 x*] is displayed End 1 * x represents desired weighing unit Page 10 of 16
Ref.. 5.1.1. Using the Mode Key Start Change balance to counting mode Change balance to percentage mode 1 PCS previously set as Unit2 from main menu Press and hold T key until [Unit2] is displayed % previously set as Unit2 from main menu Press and hold T key until [Unit2] is displayed Place number of pieces required as reference on pan Press T key briefly and continuously until [Unit2 PCS] is displayed Place reference weight on weighing pan Press T key briefly and continuously until [Unit2 %] is displayed Press and hold MODE key until [Unit2 PCS] is displayed Press and hold T key to save and return to main menu Press and hold MODE key until [ref 100%] is displayed Press and hold T key to save and return to main menu Release MODE key to select the reference weight and to switch automatically to Unit2 Release MODE key to set reference weight as the selected percentage and to switch automatically to Unit2 Remove number of pieces used to set reference weight and place the weight that needs to be counted Remove reference weight and place desired sample Read the number of pieces from the display Read the percentage of the reference weight from the display 1 End Page 11 of 16
Ref.. 5.1.2. Calibration Start Allow a warm up time of about 10 minutes after balance is switched on Press and hold T key until [CAL] is displayed Digital display [--0000g] continues to flash Remove anything that may be present on weighing pan Allow [0000g] to be displayed Wait until display flashes [--1000g] Place standard 1000g on centre of weighing pan Wait until display shows a stable [1000g] Balance returns to weighing mode End Page 12 of 16
Ref.. 5.1.3. Maintenance Start Balance needs cleaning Disconnect balance from power supply Any surrounding powder Remove using a fine brush Any spilt material Remove using a moistened cloth with a mild cleaning agent Air bubble in spirit level is in centre of marked circle Manipulate adjustable feet until this is accomplished End Page 13 of 16
Ref.. 6. Precautions 6.1. Do not install near extremes of heat and cold. 6.2. Protect balance from dust and air draughts. 6.3. Keep weighing pan clean and dry to prevent inaccuracies. 6.4. Do not move balance during weighing. 6.5. Ensure that the maximum tolerate weight of 180g is not exceeded during weighing procedures and also when using the tare function. 6.6. Do not leave any items on the balance when this is not in use. 6.7. Only use balance if the spirit level is correct. 6.8. Adjust the air bubble in the spirit level each time the balance is to be moved to another location. 6.9. If an error message is displayed when balance is switched on, switch balance off and on again. If error message re-appears, contact supplier for further information. 6.10. Avoid static charge buildup of the material to be weighed and of the weighing container. 6.11. When transferring balance to a significantly warmer environment, allow it to acclimatise for approximately 2 hours at room temperature after it has been disconnected from the mains. 7. References N/A 8. Appendices /A1 Configuration Parameters Table 9. Revision History Version Number Amendments/ Reasons for change 01 Initial Release Page 14 of 16
Ref.. /A1 Configuration Parameters Table Configuration Parameter Display Symbol Function Basic unit of balance Unit1 To choose the weighing unit to be set as Unit1 Calibration CAL To choose whether to carry out calibration [CAL YES] or to disable this function [CAL NO] Baudrate bdr To choose the desired baudrate from [300 bdr], [600 bdr], [1200 bdr], [2400 bdr], [4800 bdr] or [9600 bdr] Parity PAr To choose between having no parity [PAr no], an odd parity [PAr odd] or an even parity [PAr E] Printing Print To choose between no printing [Print no], single printout of each value [Print UST], single printout of each stable value [Print ST],auto printout after changing load [Print Lch] or continuous printout [Print PEr] Combined print function Prt-ALL To combine a printout with weighing result, date and time etc [Prt-ALL YES] or else to disable this function [Prt-ALL no] Delay Printout Prt-dEL To delay printout by 0.5, 1 or 2 seconds or else to disable this delay function [Prt-dEL no] Last Digit LASt d To choose whether the last digit is to be always visible [LASt d on] or only visible when stable [LASt d off] Automatic zero adjustment A-ZEro To choose whether this is to be switched on [A-ZEro on] or off [A-ZEro off] Menu Inhibit LAtch To choose whether to inhibit changes from being made to the configurations parameters menu [LAtch on] or else to disable this option [LAtch off] Page 15 of 16
Ref.. Status Printout StAtUS Prt To perform a printout of all the information available about the balance including the parameters that are set in the main and configuration menus Page 16 of 16