Bw500 Manual - [Unlimited PDF]
ENTER SITE »»» DOWNLOAD PDF
CLICK HERE »»» BOOK READER
Status: AVAILABLE |
Last checked: 10 Minutes ago!
In order to read or download Bw500 Manual - [Unlimited PDF] ebook, you need to create a FREE account.
Download Now! |
eBook includes PDF, ePub and Kindle version
✔ Register a free 1 month Trial Account. |
✔ Download as many books as you like (Personal use) |
✔ Cancel the membership at any time if not satisfied. |
✔ Join Over 80000 Happy Readers |
Bw500 Manual - [Unlimited PDF]
The unit will work with any Can retrofit to LVDT Tip: If you want to print a large file, download it to your PC first. Watch step-by-step instructions on how to. Belt load and speed signals are processed for accurate flow rate and totalized weight of bulk solids. Its proven load cell balance function eliminates matching of load cells. Operating in tandem with two or more weighfeeders, the BW500 may be used for ratio blending and controlling additives. Batching, load out, and alarm functions are also provided by the BW500. Please find more information here. All rights reserved. Privacy and Cookies Policy Terms and Conditions Returns and Refunds Policy. Click here to find out more Delivery prices below are Exc VAT. You will be informed by our sales team of the delivery costs and ask to confirm the order before any items are sent out for delivery.Please select your country so we can provide you with delivery date and cost estimates. Fill in the below to get started. Let us know what country you are in. Please request a quote and we will get back to you with a shipping price. Most changes are minor corrections and do not affect operating procedures. Acrobat Reader is available free from the Adobe website whose link is on the left. The data is stored in the original instrumentation and can be easily retrieved on the display. Download the manual and check the predefined tracks; anyway you can always set a new track manually. If your intermediate times show that you are faster than on your previous best lap the processor anticipates that this lap will be your new best time. The indicator for the fastest lap lights up. In this way at any point of the track you will know if you are riding or not the best lap with a quick glance. La passione per l'elettronica e per i motori ci ha spinto a far crescere la nostra azienda e portare il nostro marchio sulle piste di tutto il mondo! Browsing the site you accept the use of cookies Accept.
http://acspquebec.com/userfiles/cressida-manual-conversion-for-sale.xml
- Tags:
- bw500 manual, bw500 manual pdf, milltronics bw500 manual, siemens bw500 manual, milltronics bw500 manual pdf, accumass bw500 manual, siemens milltronics bw500 manual, dmr-bw500 manual, panasonic dmr bw500 manual, bw500 manual, bw500 manual, bw500 manual, bw500 manual headphones, milltronics bw500 manual, siemens bw500 manual.
Please complete the form below and we will get back in touch as soon as we can. Part Number: A5E33482052. Title: Manual, Milltronics BW500 and BW500L, English This agreement applies as between you, the User of this Web Site or Purchaser and Parmley Graham Limited the owner(s) of this Web Site. Your agreement to comply with and be bound by these Terms and Conditions is deemed to occur upon your first use of the Web Site. If you do not agree to be bound by these Terms and Conditions, you should stop using the Web Site immediately. No part of this Web Site is intended to constitute a contractual offer capable of acceptance. The Purchaser's order constitutes a contractual offer and our acceptance of that offer is deemed to occur upon our sending an email to the Purchaser indicating that the order has been accepted for processing. Unless expressly agreed by us in writing, any other terms or conditions, including any which may be contained in your orders, are excluded. Unless expressly incorporated in our quotation or tender, all descriptions, illustrations, drawings, dimensions, weights, measures, specifications, standards of performance or other descriptive matter of precontractual statement are approximate only and shall not form part of the contract. Parmley Graham Limited is not responsible for these charges and we undertake to make no calculations or estimates in this regard. If a Purchaser is buying internationally, they are advised to contact their local customs authorities for further details on costs and procedures. The Purchaser of the Goods will also be the importer of record and as such should ensure that the purchase is in full compliance with the laws of the country into which the Goods are being imported. Please be aware that Goods may be inspected on arrival at port for customs purposes and Parmley Graham Limited gives no guarantee that the packaging of the Goods will be free of signs of tampering.
http://dfwsedan.com/nbloom/fckuploads/cressida-manual-conversion.xml
During our contract review we are legally obliged to take into account any Export Restrictions, Sanctions or Embargoes in force at the time from the UK Government, European Union or UN ( US export regulations may also apply to some products) and such restrictions may prevent supply of the goods. Should an Export License be required, or additional documentation including Certificates of Origin, it may be necessary to apply additional costs. By continuing to use this Web Site you represent and warrant that: Your creation of an Account is further affirmation of your representation and warranty. Parmley Graham Limited accepts no liability for any losses or damages incurred as a result of your Account details being shared by you. If you use a shared computer, it is recommended that you do not save your Account details in your internet browser. If you have reason to believe that your Account details have been obtained by another without consent, you should contact Parmley Graham Limited immediately to suspend your Account and cancel any unauthorised purchases that may be pending. Please be aware that purchases can only be cancelled until they are dispatched. In the event that an unauthorised purchase is dispatched prior to your notifying us of the unauthorised nature of the purchase, Parmley Graham Limited accepts no liability or responsibility and you should make contact with the Carrier detailed in the Purchase Information. We shall be entitled to charge interest on overdue accounts at the rate of 1.5 per month. (b) Where the contract is to be or may be fulfilled in separate installments deliveries or parts, payment for each such installment, delivery or part shall be made as if the same constituted a separate contract. We reserve the right to choose the method of transport, to charge for deliveries, and charge you with manufacturers' carriage charges for special items.
Written notice of any non delivery must be received at our branch within seven days after the date of invoice. Time is of the essence of this clause. Our liability in respect of any claim accepted under this clause is limited to making up the shortage or replacing any goods proven to have been damaged or lost in transit to the point of delivery, and we accept no liability for any loss or damage suffered by you whether direct or consequential and howsoever arising. Stock indications are provided on the Web Site; however these may not take into account sales that have taken place during your visit to the web site. If the customer fails for whatever reason to take delivery of the goods on the due date the Company will be entitled to store the goods and then risk in the goods will pass to the customer, delivery will be deemed to have taken place and the customer will pay all costs and expenses including storage and insurance charges arising from its failure. You will store the goods in such a way that they are readily identifiable as our property, but you may, as trustees for us, sell them to a third party in the normal course of your business. Upon any sale by you of the goods (either alone or with other items) all rights which you have against the buyer shall automatically vest in us. We shall be entitled immediately after giving notice of our intention to repossess, to enter upon any premises with such transport as may be necessary and repossess any goods to which we have title under this clause. We cannot accept any responsibility either in respect of the installation of any goods or as to the ultimate performance of any product in which the goods may be installed. We shall in no way be liable for any direct or consequential damage, loss or expense arising from any defect or inefficiency caused by the manner in which the goods are used. Accordingly, we shall pass on to you the benefit of the warranty, if any, given by the manufacturer of the goods.
http://www.indianantique.com/images/canon-uc5500-manual.pdf
Our liability under this clause shall be in lieu of any warranty or condition implied by law as to the quality or fitness for any particular purpose of the goods, and we shall not be under any liability, whether in contract, tort or otherwise, in respect of any defects in goods delivered or for any injury, damage or loss resulting from such defects or from anything done or omitted in connection with the goods or from any work done in connection therewith. All goods returned must be securely packed and consigned carriage paid. In all cases we reserve the right to make a handling charge, and the issue of our goods received note will not bind us to issue any credit in respect of the goods. The information is provided by Parmley Graham Limited and whilst we endeavour to keep the information up-to-date and correct, we make no representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability or availability with respect to the website or the information, products, services, or related graphics contained on the website for any purpose. Any reliance you place on such information is therefore strictly at your own risk. However, Parmley Graham Limited takes no responsibility for and will not be liable for the website being temporarily unavailable due to technical issues beyond our control. For the purposes of this Privacy Policy, references to “we”, “us” or “the organisation” shall refer to Parmley Graham Limited. The organisation is the data controller of your personal data and is responsible for complying with data protection laws. The organisation is committed to being transparent about how it collects and uses that data and to meeting its data protection obligations. This may include: There are a number of other reasons we use your personal data, as explained in the list below. Where we list legitimate interests as a reason, we also describe below what we believe these legitimate interests are.
We will usually only ask for your consent when providing marketing information to you, including information about other products and services. This will be made clear when you provide your personal information. If we ask for your consent we will explain why it is necessary. We share only the personal information they need to perform their specific services and they may only use your data for the reasons we’ve described. We have internal policies and controls in place to try to ensure that your data is not lost, accidentally destroyed, misused or disclosed, and is not accessed except by its employees in the performance of their duties. Please keep us informed if your personal information changes during your working relationship with us. However, if you do not believe this is the case, please contact us by using the details shown in your documentation and you can ask us to update or amend it. However, this will need to be balanced against other factors, for example according to the type of personal information we hold about you and why we have collected it, there may be some legal and regulatory obligations which mean we cannot comply with your request. Once transferred, the other party will be responsible for looking after your personal information. Please see the Marketing section at the end of this page for more information. Where we do this, you have the right to withdraw your consent to further use of your personal information. Or go online to (opens in a new window; please note we can't be responsible for the content of external websites). Before connecting, operating or adjusting this product, please read the instructions completely. Please keep th is manual for fut ure reference. Region manage ment informatio n BD-Video This unit plays B D-Video marked with labels containing the region code B. Example: DVD-Video This unit plays DVD-Video marked with labels containing the region numb er “2” or “ALL”.
Example: This Blu-ray Disc Recorder is for viewing and recording free to view channels only, not pay TV or e ncry pted ch annels. T rademark of the DVB Dig ital Video Broadcasting Project ( 1991 to 1996) Declaration of Conformity No. 5807, 16th July 2008 Notice for DVB f unctions. An y f unct ion re lated to DV B ( Digital Video Broadcasting) will work i n areas where DVB-T (MPE G2, MPEG4-A VC) digital terrestrial broadcasting is received. Consult your local Panasonic dealer with coverage areas. ? This unit has the capabi lity for DVB specifications.Haga su pregunta aqui. Proporcione una descripcion clara y completa del problema y su pregunta. Cuantos mas detalles proporcione para su problema y pregunta, mas facil sera para otros propietarios de Panasonic DMR-BW500 responder adecuadamente a su pregunta. Haz una pregunta Acerca de Panasonic DMR-BW500 Este manual pertenece a la categoria Reproductores Blu-ray y ha sido calificado por 1 personas con un promedio de 7.1. Este manual esta disponible en los siguientes idiomas: Ingles. ?Tiene alguna pregunta sobre Panasonic DMR-BW500 o necesita ayuda. Haz tu pregunta aqui Especificaciones de Panasonic DMR-BW500 Marca Nuestra base de datos contiene mas de 1 millon de manuales en PDF de mas de 10.000 marcas. Cada dia anadimos los ultimos manuales para que siempre encuentres el producto que buscas. Es muy sencillo: simplemente escriba el nombre de la marca y el tipo de producto en la barra de busqueda y podra ver instantaneamente el manual de su eleccion en linea de forma gratuita. ManualPDF. es Si continua utilizando este sitio asumiremos que esta de acuerdo. Leer mas Estoy de acuerdo. Milltronics weighfeeder. It process both weight and speed signals and outputs accurate readings of flow rate and totalized weight of bulk Can retrofit to LVDT belt scales with an Compatible with Siemens Milltronics. For optimum performance and safety, please read these instructions carefully. Please keep this manual for future reference.
Any function related to DVB (Digital Video Consult your local Panasonic dealer with coverage areas. Consult your local Panasonic dealer with coverage areas. ? This unit has the capabi lity for DVB specifications.Zeptejte se zde. Poskytnete jasny a komplexni popis problemu a vasi otazku. Cim vice podrobnosti uvedete ke svemu problemu ve vasi otazce, tim snazsi bude pro ostatni majitele Panasonic DMR-BW500 vasi otazku zodpovedet. Zeptejte se O Panasonic DMR-BW500 Tato prirucka patri do kategorie Blu-ray prehravace a byla ohodnocena 1 lidmi prumernym hodnocenim 7.1. Tato prirucka je k dispozici v nasledujicich jazycich:Anglictina. Mate dotaz ohledne Panasonic DMR-BW500 nebo potrebujete pomoc. Zeptejte se zde Specifikace Panasonic DMR-BW500 Znacka Nase databaze obsahuje vice nez 1 milion prirucek ve formatu PDF pro vice nez 10 000 znacek. Kazdy den pridavame nejnovejsi prirucky, takze vzdy najdete produkt, ktery hledate. Je to velmi jednoduche: staci zadat znacku a typ produktu do vyhledavaciho pole a muzete si okamzite prohlednout prirucku vaseho vyberu online a zdarma.Pokud budete nadale prohlizet nase stranky predpokladame, ze s pouzitim cookies souhlasite. Vice Souhlasim. Consult your local Panasonic dealer with coverage areas. ? This unit has the capabi lity for DVB specifications.Ask your question here. Provide a clear and comprehensive description of the issue and your question. The more detail you provide for your issue and question, the easier it will be for other Panasonic DMR-BW500 owners to properly answer your question. Ask a question About the Panasonic DMR-BW500 This manual comes under the category Blu-ray players and has been rated by 1 people with an average of a 7.1. This manual is available in the following languages: English. Do you have a question about the Panasonic DMR-BW500 or do you need help. Ask your question here Panasonic DMR-BW500 specifications Brand ManualSearcher.com ensures that you will find the manual you are looking for in no time.
Our database contains more than 1 million PDF manuals from more than 10,000 brands. Every day we add the latest manuals so that you will always find the product you are looking for. It's very simple: just type the brand name and the type of product in the search bar and you can instantly view the manual of your choice online for free. ManualSearcher. com If you continue to use this site we will assume that you are happy with it. Read more Ok. Local push button station: Siemens start, stop This device is shipped with the Siemens. 29 Mar 2017 Another reason for the push towards automation is that owners are constantly.Menu Push Button Panels; Micro Panels.Use Peatix for any event and ticketing needs! Co-organizers can edit group and event pages, access sales and attendee information, manage ticket sales and more. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. User-Friendly Manuals. Product Instructions. These warning notices are accompanied by a clarification of the level of caution to be observed. Qualified personnel are only authorized to install and operate this equipment in accordance with established safety practices and standards. Unit Repair and Excluded Liability: The user is responsible for all changes and repairs made to the device by the user or the user s agent. All new components are to be provided by Siemens Milltronics Process Instruments Inc. Restrict repair to faulty components only. Do not reuse faulty components. Warning: Cardboard shipping package provides limited humidity and moisture protection. This product can only function properly and safely if it is correctly transported, stored, installed, set up, operated, and maintained. This product is intended for use in industrial areas. Operation of this equipment in a residential area may cause interference to several frequency based communications.
Note: Always use product in accordance with specifications. Copyright Siemens Milltronics Process Instruments Inc All Rights Reserved This document is available in bound version and in electronic version. We encourage users to purchase authorized bound manuals, or to view electronic versions as designed and authored by Siemens Milltronics Process Instruments Inc. Siemens Milltronics Process Instruments Inc.Disclaimer of Liability While we have verified the contents of this manual for agreement with the instrumentation described, variations remain possible. Thus we cannot guarantee full agreement. The contents of this manual are regularly reviewed and corrections are included in subsequent editions. Please check the website shown below for the latest manual revisions. We welcome all suggestions for improvement. Technical data subject to change. MILLTRONICS is a registered trademark of Siemens Milltronics Process Instruments Inc. Contact SMPI Technical Publications European Authorized Representative at the following address: Technical Publications Siemens AG Siemens Milltronics Process Instruments Inc. Under Process Instrumentation, select Level Measurement and then go to the manual archive listed under the product family. Under Weighing Technology, select Continuous Weighing Systems and then go to the manual archive listed under the product family. The Milltronics BW500 is a full-featured integrator for use with belt scales and weigh feeders. The speed and load signals from the conveyor and scale, respectively, are processed to derive rate of material flow, and totalization. The primary values of speed and load, and the derived values of rate and total are available for display on the local LCD, or as output in the form of analog ma, alarm relay and remote totalization. BW500 supports Siemens Milltronics Dolphin Plus software and Modbus protocol on the two RS-232 ports and the RS-485 port for communication to customer PLC or computer.
Safety Notes Special attention must be paid to warnings and notes highlighted from the rest of the text by grey boxes. Note: means important information about the product or that part of the operating manual. The Manual It is essential that this manual be referred to for proper installation and operation of your BW500 belt scale integrator. As BW500 must be connected to a belt scale, and optionally a speed sensor, refer to their manuals as well. This product is susceptible to electrostatic shock. Follow proper grounding procedures. Recommend drilling the enclosure with a hole saw and the use of suitable cable glands to maintain ingress rating.Use grounding type bushings and jumpers. If you are ready to install your SmartLinx module, or want to change it, please follow the instructions as outlined. Installation Refer to: 1. Isolate power and voltages applied to the BW Open the lid. 3. Install the module by mating the connectors and secure in place using the two screws provided. 4. Route communication cable to SmartLinx module along the right side of the enclosure wall. This route will reduce communication. Note: Refer to the SmartLinx module documentation for any required hardware settings prior to closing the lid. 5. Close the lid. 6. Apply power and voltage to the BW500. SmartLinx Module in the Specifications section on page 3, P750 P769 SmartLinx Module Specific Parameters on page 130 in this manual, the SmartLinx manual for wiring. Page 8 Milltronics BW500 - INSTRUCTION MANUAL 7ML19985DK04 15 Installation Refer to: 1. Isolate power and voltages applies to the BW Open the lid. 3. Install the board by mating the connectors and secure the card in place using the 3 screws provided. 4. Close the lid. 5. Apply power and voltage to the BW500. However these may not be run in the same conduit as high voltage contact or power wiring. Ground shield at one point only. Insulate at junctions to prevent inadvertent grounding.
Not all components or their maximum quantity may be required. Page 10 Milltronics BW500 - INSTRUCTION MANUAL 7ML19985DK04 17 Scale One Load Cell load cell Siemens Belt Scale R E D B LK G RN W HT S HL D Note: Colour code for load cells used on Siemens weighfeeders may be different than shown. Please refer to the weighfeeder wiring diagram. Installation 7ML19985DK04 Milltronics BW500 - INSTRUCTION MANUAL Page 11 18 Scale Two Load Cell load cell A load cell B Siemens Belt Scale R E D B LK G RN W HT G R N W HT S HL Note: Colour code for load cells used on Siemens weighfeeders may be different than shown. If a speed sensor is used, insure that the jumper is removed. Note: With contact closed or jumpered when the conveyor is idle, the integrator will continue totalizing. Main Speed Sensor MD Series RBSS or ENCODER wht blk red Installation Shields are common, but not grounded to chassis. Run cable shields through SHLD terminals and ground at BW500 only. Connect the BW500 terminal 16 to speed sensor terminal: 2 for clockwise speed sensor shaft rotation 3 for counter-clockwise speed sensor shaft rotation. Speed sensor shaft rotation is viewed from the front cover of the speed sensor enclosure. If a speed sensor other than the models shown is supplied, consult with Siemens for details. A second speed sensor input can be added using the Auxiliary inputs: the second speed input allows calculation of Differential Speed. For more information, see Auxiliary Inputs (P270) on page 113. Connect the BW500 terminal to speed sensor terminal: 2 for clockwise speed sensor shaft rotation 3 for counter-clockwise speed sensor shaft rotation. Input device in the form of open collector transistor or dry contact across BW500 terminals will also serve as a suitable speed signal.
Installation 7ML19985DK04 Milltronics BW500 - INSTRUCTION MANUAL Page 17 24 Auxiliary Inputs Customer dry contacts, or open collector transistor output supplied as required Refer to P270 on page 113 for programming details. Auto Zero Prefeed activated dry contact Refer to Auto Zero on page 41. RS-485 Port 2 Daisy Chain customer device Installation Terminal Device customer device Page 20 Milltronics BW500 - INSTRUCTION MANUAL 7ML19985DK04 27 RS-232 Port 3 Note: Jumper pins 4-6 and 7-8 when using hardware flow control. Otherwise, leave them open. An on board capacitor provides 20 minutes of charge to preserve the memory while the battery is being changed. Notes: Do not install the memory backup battery until the BW500 is installed, as it begins operation immediately. Insert the battery into the holder as shown in the following diagram before using the BW500. Disconnect power before installing or replacing the battery. Installation Steps 1. Open the enclosure lid. 2. Slide the battery into the holder. Page 22 Milltronics BW500 - INSTRUCTION MANUAL 7ML19985DK04 29 RUN ALT DISP PAR RESET TOTAL ZERO CLEAR A M SPAN EN TER Start Up Note: For successful start up, ensure that all related system components such as thebelt scale and speed sensor are properly installed and connected. When the unit is initially powered, it starts in the PROGRAM mode PROGRAM Mode The PROGRAM parameters define the calibration and operation of the BW500. By entering the PROGRAM mode, the user can view the parameter values or edit them to suit the application. PROGRAM Mode Display VIEW P001 Language V 1-Eng 1 EDIT P001 Language E 1-Eng 1 To enter the PROGRAM mode Press P001 Language V 1-Eng 1 To select a parameter The default of previous parameter view is displayed. e.g. P001 is the default parameter for initial start up. Scroll: Press to move up, P002 Test Reference Selection V 1-Weight, 2-Chain, 3-Ecal 1 e.g. scrolls up from P001 to P002.
Attempting to enter the RUN mode without satisfying the program requirements forces the program routine to the first missing item. Initial Start Up Initial start up of the BW500 consists of several stages, and assumes that the physical and electrical installation of the belt scale and speed sensor, if used, is complete: power up programming load cell balancing zero and span calibration Power Up Upon initial power up, the BW500 displays: P001 Language V 1-Eng 1 The initial display prompts the user to select the preferred language. Note: This manual only lists English as a choice of language. However, your BW500 will list additional languages. Programming Press The BW500 then scrolls sequentially through the start up program as parameters P001 through P017 are addressed. P002 Test Reference Selection V Select 1-Weight, 2-Chain, 3-Ecal 1 e.g. Accept weight (supplied with scale) as the test reference.e.g. Press Start Up P003 Number of Load Cells V Enter Number of Load Cells 2 e.g. Accept 2 as the number of load cells. Page 26 Milltronics BW500 - INSTRUCTION MANUAL 7ML19985DK04 33 Press P004 Rate Measurement System V Select 1-Imperial, 2-Metric 2 e.g. Accept 2 for measurements in metric. Press select: 1- calculated value, the program returns to P015. Calculate the value per Parameter P690. P Speed Constant Entry E 1-Calculated, 2-Sensor Data 1 P Step 1: Drive Pully Diameter: Diameter V 0.00 mm P Step 2: Pulses per sensor Rev. V Enter Pulses 0.00 select 2- sensor date, the program advances through parameters P691 and P692 prompting entry from the sensor nameplate. From this data, the speed constant is calculated and automatically entered into P015. For manual or automatic calculation, refer to P690 on page 127. For manual or automatic calculation, refer to P017 on page 106. The test load value should be less than the design load (P952). If not, contact Siemens. To ensure proper entry of all critical parameter values, return to P002 and review parameters through to P017.
In the case of ECal, the load cells are balanced by the ECal procedure. If you are operating a two or four load cell belt scale, it is recommended that the load cells be balanced electronically prior to initial programming and calibration, or after either or both load cells have been reinstalled or replaced. Unbalanced load cells adversely affect the performance of your belt conveyor weighing system. With the conveyor stopped and locked out, lift the belt off the weighing idlers. Balancing the load cells requires a subsequent zero and span recalibration Balancing of the load cells is now complete, and is followed by a zero and span calibration. Start Up Page 32 Milltronics BW500 - INSTRUCTION MANUAL 7ML19985DK04 39 Zero Calibration Note: To obtain an accurate and successful calibration, ensure that the required criteria are met. Refer to Calibration Criteria on page 141. Press Zero Calibration: Current Zero 0 Clear belt. Press ENTER to Start the current zero count Press Initial Zero Calibration. Press Calibration Complete. Deviation 0.00 Press ENTER to accept value: Press Zero Calibration. Current Zero Clear belt. Press ENTER to Start the deviation from previous zero. For an initial zero there is no previous zero; hence the deviation is 0. for example, the new zero count, if accepted for example, the new zero count, if accepted Accepting the Zero returns to start of Zero. A new Zero can be performed, or continue to Span. Note: The moisture meter is ignored during calibration. If Inclinometer is used, then calibration is adjusted based on incline angle. Note: To obtain an accurate and successful calibration, ensure that the required criteria are met. With the conveyor stopped and locked out, apply the test weight or chain to the scale as instructed in the associate manuals; Then start the conveyor. Press Span Calibration. Current Span 0 Setup test.
Add new comment