November 2, 2012
Integration – What questions should we ask equipment vendors?
Integration is a broad term used in quality circles to describe anything from manually merging data output from two different systems – such as a Material Requirements Planning (MRP) and Statistical Process Control (SPC) – to commanding Programmable Logic Controllers (PLC’s) from quality data input. Integrating systems, software, machines and instruments can provide many desirable benefits such as increased throughput, ease of use, and increased accuracy. So, what questions can be asked of equipment vendors to ensure your new device is “integration friendly”?
Can the instrument interface with a PC? There are a variety of ways that an instrument or device and transfer data to a PC. These include:
- RS-232 (Serial) – This provides a universal COM connection which enables the user to control the data stream independent of other peripherals that may use USB or other plug-and-play connections. This connection will likely require a driver to be installed which, generally, is provided by the device manufacturer.
- USB – This connection is typically the simplest way of transferring data from device to PC, though your PC may treat the device as keyboard input rather than a separate COM connection. A driver (provided by the device manufacturer) may be available to allow configuration and control similar to a RS-232 connection.
- TCP/IP – This connection enables the data stream to be read over a local area network (LAN). Some devices have direct TCP/IP connections (Ethernet) or you can use a third party serial-IP converter. Converters are available in both wired and wireless varieties. TCP/IP is typically the most efficient way to transmit a signal to a PC over long distances, as serial cables have length limitations.
- Flat File – Some devices have the option of creating a flat file containing the output data stream. The user can configure where the flat file is saved on the PC or network drive so that it can be accessed by a data collection or SPC system.
- OPC Server – An OPC server is a piece of software that can interact with PLCs (Programmable Logic Controllers). If a device is connected (or can be connected) to a PLC network then an OPC server provides a convenient means of sampling and making tags available for data collection and SPC systems.
- Database – Some devices are capable of writing directly to a database such as Oracle, SQL or historian. This connection can provide an easy way of archiving data while also providing a means to query and sample these data by a data collection or SPC system.
It is possible that some devices may be able to communicate in multiple ways, so it is important to understand from the device manufacturer which options apply to your device.
Does the device require proprietary software to configure data output? Software may allow for more versatility with data output, enabling you to change settings with an easy-to-use interface. Other devices may require configuration on the device itself via analog controls or a digital screen. There are perks for each system. Keep in mind, though, that proprietary software may reduce portability. For example, if you would like to move a device to a new PC, software may have to be installed to configure the device and set the desired data output rather than having settings move with the device itself.
What does the data output stream or flat file look like and can it be manipulated? In general, data output becomes more sophisticated as the functionality of the equipment increases. For instance, a digital caliper with a serial PC connection may send a data stream that includes the measurement reading plus a carriage return. A moisture analyzer, on the other hand, may be able to return ambient temperature, ambient moisture, % moisture (in real-time throughout the test), % moisture (once the test in complete), etc. It is important to verify the data stream output of the equipment and ensure that all desired data is (or can be) included in the output. It is also important to verify the type of data output such as digital or analog output stream or if the device has the capability of exporting flat files. More options will allow for more versatility and opportunity for integration.
With all of these capabilities, it is best if you can see them directly. Ask if you can see an example of the device’s output. Sometimes you can do this directly by using a tool like Hyperterminal to see RS-232 or TCP/IP data, and sometimes it can be provided by the vendor as a text file or screenshot.
Integration of systems and equipment can be extremely valuable, so it is important to ask equipment vendors the right questions to ensure that you can take advantage of the information available to you. It is critical to understand the capabilities of your equipment so you know what possibilities exist. A little up front work will pay out with any integration project.