What is the difference between dh485 and rs485

Looking at the table, we can see that, although there is only a single generation gap, ControlLogix or are quite homogeneous. In controller connections, there is quite a difference in both processors. On the other hand, can go up to 1 Gbps, which is a huge speed and reliability improvement.

Talking about the CompactLogix, there is another significant difference between generations. In comparison to the previous generation, Allen Bradley made significant improvements. Before the introduction of Foundation Fieldbus, the gateway to the industrial automation started with parallel wiring, where the devices were connected independently with the rule and control level.

However, with the increased levels of automation, the number of participants also increased. This led to a high wiring expenditure. Hence, it was extensively replaced by economical and faster Fieldbus systems.

Foundation Fieldbus systems are targeted for platforms using advanced as well as primary regulatory control, along with some of the discrete commands associated with those functions. The technology was previously used in the process industries; however, with recent advancements, Foundation Fieldbus are now being applied in power plants as well. Field and Bus make Fieldbus. A field is a geographically limited area. In an engineering world, it is intellection of the plant levels.

Bus, on the other hand, is a set of a standard line that electrically links multiple circuits for transferring information. The idea behind Fieldbus is to eliminate any point-to-point links between the field devices like actuators and sensors and their controllers by a single digital connection on which all the information is communicated consecutively in serial order and multiplexed over time.

In most cases, the Fieldbus transfers the information in small packets in a sequential manner. The subsequent transmission of information decreases the total required number of connecting lines over greater distances than that of parallel transfers.

Within the process automation environment, there are two related applications of Foundation Fieldbus. They use different communication speeds and physical media.

Considering the mentioned benefits of Foundation Fieldbus, there are plenty of reasons why it is implemented in many automation industries. So of them are as follows:. The DL can be programmed with other firmware versions to perform other protocol conversions, such as;. So what options are out there for the plant to continue working until they are ready for an upgrade to Industrial Ethernet IP?

More details and other application notes on Equustek DL can be found from this link. Profibus and Profinet are two terms that are often confused with each other, both of them being field networks part of industrial automation protocols.

However, there are significant differences between the two in various aspects and for the same reason are used for different purposes in industries. In order to clearly understand their functioning and application of the two, it is important to first get a good grasp of the basics.

Profibus which is the acronym for Process Field Bus is basically a standard for fieldbus communication used in automation technology. Profinet on the other hand, which is acronym for Process Field Net is a standard for internet communication over industrial Ethernet.

As they are both very popular and highly sought after automation protocols created by the same organization, they do share a number of similarities. They are both created and maintained by Profibus and Profinet International.

However, Profinet comparatively has extra advanced capabilities that facilitate a faster and a more flexible field of communication within a network. They share the same application profiles; which essentially implies that they have similar guidelines followed by different categories of devices within a network, regarding their use of Profibus and Profinet data during communication.

These profiles enable smooth planning and functioning of the automation systems and devices. Other than that they are also very similar in terms of their engineering concepts and they use General Station Description files to define the hardware for each device. The file type however is different. In simple terms Profibus is a classic and traditional automation protocol based on serial communication while Profinet is a newer enhanced automation protocol based on Industrial Ethernet.

Profibus and Profinet use GSD files for define the hardware for various devices. But as mentioned before, the difference lies in the type of file being used. In terms of their base field, Profinet made the move from RS to Ethernet to become more efficient and ubiquitous.

It is a more adaptable and modern technology that helps organizations future-proof their processes. Besides that, being based on industrial Ethernet, Profinet also enjoys a higher bandwidth, a larger size of message and unlimited amounts of address space.

Separate controllers attached to the network may have to adhere to certain limitations in terms of address space, depending on their memory capacity and processor capabilities though. Hence, there is no delay in information exchange. Besides that, Ethernet networks are generally switched networks that are practically devoid of network collisions. AWT is not writing. Thanks in advance.

Actually, it would be helpful to see the working ML example too, if that's possible. And what is the display? Hello Attached is the ML working program. The display is a production display with RS communication, Through Channel1 I am sending 2 bytes and receiving 32 bytes with the actual count. My approach would be to get the ML working with the converter, then eliminate the converter. I'm noticing that the communications configuration in the two programs is not identical.

I'm a little shaky with serial protocols especially given the multitude of variations , so I like to eliminate as many variables as possible when testing.

RSS Edited 3 Mar by asteroidehk. Try wiring Channel 0 up for RS using the converter. Does that work? My guess is that there is a problem with the way you have the direct RS wiring. So there's a problem with Ch0, whether you are using the converter or not. The only difference between my communications setup and the one in the file you attached was that I used a baud rate where you are using I also used the AWA instruction, but the only difference between that and the AWT is that it appends the termination characters to the outgoing message.

The only thing in the program that looks suspicious is that you are clearing the buffers when the ARL instruction completes, so if the AWT instruction stuck, it might not send. How do you have it wired up? I used a standard Micrologix programming cable when I did my application. Another worse idea is that the Ch0 port is fried. Can you connect to the PLC on Ch0?

You'll have to put it back to DF1, of course. Create an account or sign in to comment You need to be a member in order to leave a comment Create an account Sign up for a new account in our community. Register a new account. Sign in Already have an account? It is specifically meant to be used in explosion prone or hazardous areas. The RS is also a standard, but it defines the electrical signal levels in the communication between drivers and receivers or hosts and slaves in networking.

In this case though, the electrical signalling is more balanced and multi point systems are also supported. For the same reason, the RS is a very useful and popular standard in industrial control systems. It is more so as it is capable of being connected with multiple receivers, whether in a linear or a multi drop bus and it supports both Local Area Networks as well as multi drop communication links and works with data rates up to 10 Mbits.

Both the Profibus and the RS are standards used in communication during process automation. However, they are used in different aspects of communication. Profibus is a very flexible and reliable communication technology where issues can be caused by small and simple errors. On the other hand, RS is a more balanced technology that makes use of a two-wire transmission system.