STANDARD OPERATING PROCEDURE

Transcription

1 Ref.. Table of Contents Page 1. Scope 2 2. Objective 2 3. Definitions 2 4. Responsibility 4 5. Procedure 4 6. Precautions References Appendices Revision History 17 Original Authorised Copy for: Reading Copy Written by: Reviewed by: Approved by: Signature/Date: Signature/Date: Signature/Date: Page 1 of 19

2 Ref.. 1. Scope This Standard Operating Procedure (SOP) applies to the staff and students making use of the Precisa 180A 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 180A Precision Balance. 3. Definitions 3.1. Adjustable Feet / Levelling Screws: Four circular screws situated at the bottom of the balance that are manipulated to level the balance out Automatic Calibration: A calibration procedure that is carried out automatically by the balance every 24 hours irrespective of whether it is in standby or weighing mode Calibration: A procedure performed to check a measuring instrument against an accurate standard to determine any deviations and correct for errors Configuration Parameters: A number of different options that are used to set the balance according to the user s preferences External Calibration: Involves the use of a standard external weight that must be used in order to carry out the calibration process Floating Display: A function that enables the balance to adapt its integration time to the conditions of the environment Internal Calibration: Involves the use of a standard internal weight that is used to carry out the calibration process 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: Page 2 of 19

3 Ref.. Calibration to carry out the type of calibration previously chosen from the configuration parameters menu 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 i.e seconds, 0.16 seconds or 0.32 seconds Stability Detector to choose the desired stability for the balance i.e Low, Medium or High 3.9. 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 Unit1 to Unit 2 or vice versa or else to change between percentage and counting mode On/Off Key: To switch the balance on or off 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 Tare: Allows the balance to display the weight of the sample measured only and not the combined weight of the sample and its container 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] Unit2: The secondary unit that can be chosen and programmed in the main menu. This can be set as one of the units chosen for Unit1 with the addition of the piece [PCS] or percent [%] Weighing Cell: A glass structure surrounding the weighing pan to reduce inaccuracies that might occur due to air currents or moving objects Weighing pan: The area on top of which the material to be weighed is placed. Page 3 of 19

4 Ref.. 4. Responsibility 4.1. The members of the Department of Pharmacy (staff and students) are responsible for following this SOP The designated Laboratory Officer or Laboratory Assistant is responsible for ensuring that this SOP is followed. 5. Procedure 5.1. Diagram of the Precisa 180A Precision Balance Page 4 of 19

5 Ref Installation Place the balance a stable surface, away from any vibrations Turn the adjustable feet/levelling screws at the bottom of balance clockwise or anticlockwise until the air bubble in the spirit level is in the centre of the marked circle Insert power supply connector in the plug on the rear of the balance and plug the power supply into the mains supply Press the On/Off Key to activate the balance Wait until a stable 0,0000 is displayed before use Configuration Press and hold the T key whilst balance is still switched off Press the On/Off key while still pressing the T key Keep the T key pressed until the desired configuration parameter is displayed (see /A1) Release the T key to access the desired configuration parameter Press the T key briefly but continuously until the desired function in the configuration parameter is displayed 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 Using the Main Menu Press and hold the T key until the desired option is displayed Release the T key to enter the desired sub-menu Press the T key briefly but continuously until the desired parameter in the sub-menu is reached 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 Weighing Mode 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 Page 5 of 19

6 Ref.. previously set as the basic unit i.e. Unit1 or as the secondary unit i.e. Unit Open the top lid of the weighing cell and place sample onto the weighing pan Close lid and read off value 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, close lid and read of the tared value from the display Use the tare function repeatedly if necessary Using the Mode Key Counting Mode Ensure that PCS was previously set as Unit2 from the main menu Place the number of pieces that are required as reference weight on the weighing pan Press and hold the MODE key until [Unit2 PCS] is displayed 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 Remove the number of pieces used to set the reference weight Place the weight that needs to be counted and read the number of pieces from the display Percentage Mode Ensure that % was previously set as Unit2 from the main menu Place the reference weight on the weighing pan Press and hold the MODE key until [ref 100%] is displayed Release the MODE key to set the reference weight as the selected percentage and also to switch automatically to Unit2 i.e percentage mode Remove the reference weight used to programme the percentage function. Page 6 of 19

7 Ref Place the desired sample and read the percentage of the reference weight from the display Calibration Press and hold the T key whilst balance is switched off Press the On/Off key while still keeping the T key pressed Release the T key when [CAL] is displayed Press the T key briefly but continuously until the desired calibration option is reached i.e. an internal calibration [CAL INT], an external calibration [CAL EXT] or an automatic calibration [CAL AUT] Press and hold the T key again to return to the main menu External Calibration Allow a warm up time of about 10 minutes Press and hold the T key until [CAL EXT] is displayed Ensure that there is nothing present on the weighing pan. If pan is not empty, and/or the balance is active, the digital display [--000g] will continue to flash Allow [000g] to be displayed to indicate that zero point measurement has been carried out Wait until balance display flashes [--100g] and then place the recommended calibration weight (100g) on the centre of the pan Wait until display shows [ g] to indicate that calibration is finished and balance returns to weighing mode Internal Calibration Allow a warm up time of about 10 minutes Press and hold the T key until [CAL INT] is displayed Wait until the balance reverts to weighing mode to ensure that the internal calibration is completed. Page 7 of 19

8 Ref Maintenance Disconnect balance from its power supply before attempting to clean and leave it in its normal operating position Use a clean fine brush to remove any surrounding powder Use a moistened cloth with a mild cleaning agent to clean and remove any spilt material Ensure that the air bubble in the spirit level is in the centre of the marked circle Troubleshooting Fault Display does not light up Possible Cause/s - Balance not switched on correctly - Balance not connected to mains - Power failure - Faulty microfuse OL is displayed - Weighing limit has been exceeded UL is displayed Weighing display changes continuously Result seemingly incorrect Display flashes continuously during calibration - Weighing pan and/or pan support has not been assembled properly - Draught/ air currents present - Vibrations on table/floor - Weighing pan touching a foreign body - Balance not tared - Balance not levelled - Outdated calibration - Strong temperature fluctuations - Location of balance is undesirable - Calibration weight is too imprecise or does not correspond to the recommended one (applies for external calibration) Page 8 of 19

9 Ref Flow Chart 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 0,0000 is displayed before use End Page 9 of 19

10 Ref Configuration Start Press and hold T key whilst balance is still switched off Press On/Off key while still pressing the T key Desired menu displayed Keep T key pressed until desired menu is displayed Release T key to access 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 Press and hold T Key to save and return to main menu End Page 10 of 19

11 Ref Using the Main Menu Start Press and hold T key Desired option displayed Keep T key pressed until desired option is displayed 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 Press and hold T Key to save and return to main menu End Page 11 of 19

12 Ref Weighing Mode Start Desired weighing unit displayed Desired weighing unit previously set as Unit1 or Unit2 Press On/Off key to switch off balance 1 Using tare function Open top lid of weighing cell and place sample Press and hold MODE key Press and hold T key and simultaneously press the On/Off key again Place empty weighing container on balance Close lid and read off value 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 Close lid and read off value Press and hold T key to save and return to main menu Allow balance to enter weighing mode Keep on using tare function repeatedly if necessary Press and hold MODE key until [Unit1 x*] is displayed End 1 * x represents desired weighing unit Page 12 of 19

13 Ref 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 [Unit2 %] 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 13 of 19

14 Ref Calibration Start Press and hold T key whilst balance is still switched off Press On/Off key to turn on balance while still keeping T key pressed Release T key when [CAL] is displayed Perform internal calibration Perform external calibration Perform automatic calibration Press T key briefly but continuously until [CAL INT] is displayed Press T key briefly but continuously until [CAL EXT] is displayed Press T key briefly but continuously until [CAL AUT] is displayed Press and hold the T key to return to main menu Press and hold the T key to return to main menu Press and hold the T key to return to main menu Allow balance to warm up for about 10 minutes Allow balance to warm up for about 10 minutes 3 Press and hold T key until [CAL INT] is displayed Press and hold T key until [CAL EXT] is displayed Balance reverted to weighing mode Wait until balance reverts to weighing mode Digital display [--000g] continues to flash 1 Remove anything that may be present on weighing pan Page 14 of 19 2

15 Ref.. 2 Allow [000g] to be displayed Wait until display flashes [--100g] Place standard 100g on centre of weighing pan Wait until display shows [ g] Balance returns to weighing mode 1 3 End Page 15 of 19

16 Ref Maintenance Start Balance needs cleaning Disconnect balance from power supply Leave balance in its normal operating position and do not tilt sideways Any surrounding powder Remove using clean 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 16 of 19

17 Ref.. 6. Precautions 6.1. Do not install near extremes of heat and cold Do not tip the balance on its side since weighing cell may be damaged Protect balance from dust and air draughts Keep weighing pan clean and dry to prevent inaccuracies Do not move balance during weighing Ensure that the maximum tolerate weight of 180g is not exceeded during weighing procedures and also when using the tare function Do not leave any items on the balance when this is not in use Only use balance if the spirit level is correct Adjust the air bubble in the spirit level each time the balance is to be moved to another location 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 Avoid static charge buildup of the material to be weighed and of the weighing container 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 PAG Oerlikon AG. Precisa 180A Operating Instructions. Zurich: Precisa Gravimetrics AG. 8. Appendices /A1 Configuration Parameters Table 9. Revision History Version Number Amendments/ Reasons for change 01 Initial Release Page 17 of 19

18 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 from different degrees of calibration procedures i.e. internal calibration [CAL INT], external calibration [CAL EXT], automatic calibration [CAL AUT] and no calibration [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] Signal Sound Sound To switch the sound on [Sound on] or off [Sound off] Date/Time Adjustment SEt D + T To set the time and date Page 18 of 19

19 Ref.. Menu Inhibit LAtch To choose whether to inhibit changes from being made to the configuration parameters menu [LAtch on] or else to disable this option [LAtch off] 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 19 of 19