13 replies to this topic

[TH Ame]

Hello all.

I need advise and pointers on this matter. My company is currently working on data capturing automation system. From the current system, the PLC in the factory has already been devised with sensors, display equipments and counters. Each of the machineries have their own sensing devices and display equipments. However, the main objective is to collect all the data obtained into a single system and transfer it into our database. Can some one with experience give me some pointers on this, like what product to be implemented or how this can be possible? Thanks in advance.

[Ham]

Dear Friend,

B&B Electronics can assist you in your data capturing application.

Model UD128A8D provides the hardware and software needed for a complete data acquisition system with minimal external circuitry. The USB plug-n-play interface makes it easy to configure. Power is derived from the PC's USB port. No external power supply or batteries are required. Includes 1m A-male to B-male USB cable.

• Plug-and-play USB data acquisition
• Reads data up to 16,000 samples per second
• All inputs are buffered and over-voltage protected
• 0 to 5 Volts input and output range

Analog Inputs

• 8 channels of 12-bit analog
• Configurable as 8 single-ended or 4 pairs of differential inputs
• Built-in 5V reference
• Sampling rates from microseconds to hours

For more information please visit: http://www.bb-elec.com/product.asp?sku=UD1...b&Trail=742

Regards

Hammond Yoong
Cedars Technologies
Mobile: +65 9188 1783
email: cedars@starhub.net.sg
skype: cedarsatsing
Please visit: www.bb-elec.com

Attached Files

•  Data_acq.JPG   63.27K   9 downloads

[Chee KM]

Hello all.

I need advise and pointers on this matter. My company is currently working on data capturing automation system. From the current system, the PLC in the factory has already been devised with sensors, display equipments and counters. Each of the machineries have their own sensing devices and display equipments. However, the main objective is to collect all the data obtained into a single system and transfer it into our database. Can some one with experience give me some pointers on this, like what product to be implemented or how this can be possible? Thanks in advance.

Hi,

The best thing is to use high level interface to all your machines. But you need to confirm the have ready connection to interface. Then you just need to purchase a SCADA software to link back all the data.

[TH Ame]

Hi,

The best thing is to use high level interface to all your machines. But you need to confirm the have ready connection to interface. Then you just need to purchase a SCADA software to link back all the data.

Thanks. However, based on my knowledge, SCADA's primary function is to control the process on factory floor. Won't it be too costly to implement it just for the purpose of data collection? I was thinking of implementing fieldbuses to share information between PLCs and a PC which has data capturing software (not SCADA) and transfer it back to the HQ? This is because we are implementing this on all the plywoods located round the state. However, my main concern will be the inability to link between the PLCs as well as the different PLCs (in terms of manufacturers) that are scattered round the factory floor. Pointers anyone? Thanks in advance.

[Johnson Lukose]

Hello all.

I need advise and pointers on this matter. My company is currently working on data capturing automation system. From the current system, the PLC in the factory has already been devised with sensors, display equipments and counters. Each of the machineries have their own sensing devices and display equipments. However, the main objective is to collect all the data obtained into a single system and transfer it into our database. Can some one with experience give me some pointers on this, like what product to be implemented or how this can be possible? Thanks in advance.

I would propose that you connect the PLC to the PC/IT network. The interface of choice today is Ethernet TCP/IP. Most PLC manufacturer's offer a Ethernet interface today. Check the protocol name up to version #. Modbus/TCP is an open protocol. Maybe your choice would be restricted to RS485/RS232. Again, Modbus is an open protocol. Then find an OPC Server that is compatible with the protocol. You may be lucky to find an OPC Server that can interface between Modbus/TCP and/or Modbus to ODBC or SQL database. You'll have to do an internet search to find one. Check out KEPware or Matrikon but there are thousands others.

thanks.

[James]

I would propose that you connect the PLC to the PC/IT network. The interface of choice today is Ethernet TCP/IP. Most PLC manufacturer's offer a Ethernet interface today. Check the protocol name up to version #. Modbus/TCP is an open protocol. Maybe your choice would be restricted to RS485/RS232. Again, Modbus is an open protocol. Then find an OPC Server that is compatible with the protocol. You may be lucky to find an OPC Server that can interface between Modbus/TCP and/or Modbus to ODBC or SQL database. You'll have to do an internet search to find one. Check out KEPware or Matrikon but there are thousands others.

thanks.

I agree with Johnson's proposal on using TCP/IP to send the data back to your database server (presumably a PC) since both uses TCP for communication. However, this would work well if all the PLCs are on Modbus TCP. You mentioned that you already have a lot of existing PLCs on the manufacturing floor interfacing with existing sensors. If there are older systems, I assume that the PLCs might only have serial interfaces if any & if the PLCs are from different vendors & models , different protocols (unless all supports PLCs). You need to convert serial communication back to TCP before connecting back to your Database server. You did not mention what type of database you're using or if there's an existing one or you need to do SQL commands to insert the data into an existing database record. If you're dealing with one 1 or 2 brands/models, investing in an OPC server to do the communication would be a good solution. However, you would need to have a PC running Windows installed at each site connected to the PLCs through a of gateway/switches (that converts serial to TCP) & this is connected back to the central server. This means also an extra PC on the floor to maintain. If you need a PC-less method, means you want to convert all the PLCs signals to TCP & straight back to the databse server, you would need to go with a PAC platform (there were a few discussions on PAC previously). PACs have the processing power of PCs but with ruggedness & reliability of PLCs. A PAC already has a built-in TCP port that can transfer data up to 10/100/1000 Mb & can also have multiple serial interfaces to PLCs/RTUs. The downside is, OPC server software can only run on Windows based platform, so you might need to write low level code to interface with the PLCs if it does not support Modbus. If the data that you're trying to get from the PLCs are discreet signals (on/off, counter or speed outputs, 4-20 mA), another methos would be to use the I/O capabilities to monitor the output from the PLC's I/Os, scale the values & then send it back to the server. PAC have non-volatile data storage, you can also log the data into the PAC when ever connection is lost to the server.
http://www.ni.com/pac/

[TH Ame]

hello all, thanks for the suggestions. I deemed the feedback from Johnson and James are what I have in mind. However, the field engineers will like to implement shift registers into the system because counter and control signal are current sensitive. Is it possible? How does it exactly works? Thanks in advance

[James]

hello all, thanks for the suggestions. I deemed the feedback from Johnson and James are what I have in mind. However, the field engineers will like to implement shift registers into the system because counter and control signal are current sensitive. Is it possible? How does it exactly works? Thanks in advance

What is the reason for having shift registers? Normally, shift registers are used to store data from previous iterations. Is it to remove noise? You need to check whether the I/O front end of the PLC has 50/60Hz filters for noise filtering for analog signals or de-glitching filters that will remove false counts from spikes in the counter signals. Proper shielding & wiring might help to remove noise.

[TH Ame]

This is because our plant engineer wish to compare the actual and virtual data as he said the counter and control signal is count sensitive. any idea if this is necessary or not?

[James]

This is because our plant engineer wish to compare the actual and virtual data as he said the counter and control signal is count sensitive. any idea if this is necessary or not?

I assume that virtual data means data read from the PLC's register & actual data is the actual number of pulses from the output. Where is this signal coming from, is it from a proximity sensor? How fast does this signal go from high to low & what are the voltage levels? (TTL or 0-24VDC?). If the ladder logic is written correctly & noise is not introduced into the system, the data read from the register should tally (or differs for 1 to 2 counts for reading uncertainty). The best way would be putting in an actual counter instrument or module to measure the number if pulses & compare that within a period with the data read from the PLC's register. You can use a Data Acquisition card with built-in counter module to measure this as well.

[TH Ame]

Hello again!!!!

How do I implement this project if the PLCs communication ports are all already used up by the respective HMI panel of their machines? At the same time, the manufacturers of the machines are stringent on modifications of their company's products. They will not want to have any changes to their PLCs. Help?!?!?! Thanks in advance.

[James]

Hello again!!!!

How do I implement this project if the PLCs communication ports are all already used up by the respective HMI panel of their machines? At the same time, the manufacturers of the machines are stringent on modifications of their company's products. They will not want to have any changes to their PLCs. Help?!?!?! Thanks in advance.

It would be quite difficult to interface with a proprietry system unless there's provision for the system to let you interface through a PC. Depending on the make/model of the PLCs, you might be able to interface & by-pass the HMI's without affecting the process using OPC. If the hardware does not support that, then it would be near impossible to implement a monitoring system other than using a separate set of controllers/RTUs to monitor the output of the signals in parallel to the existing PLCs.

[SAM T]

Hello all.

I need advise and pointers on this matter. My company is currently working on data capturing automation system. From the current system, the PLC in the factory has already been devised with sensors, display equipments and counters. Each of the machineries have their own sensing devices and display equipments. However, the main objective is to collect all the data obtained into a single system and transfer it into our database. Can some one with experience give me some pointers on this, like what product to be implemented or how this can be possible? Thanks in advance.

I have noticed that Moxa devices are also good and ecnomical. With their devices you can use data capturing software from www.parijat.com

[willamsstephan]

Hi,

The best thing is to use high level interface to all your machines. But you need to confirm the have ready connection to interface. Then you just need to purchase a SCADA software to link back all the data.





headerp solutions pvt ltd