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Software & Firmware Design, Specification, Development, Integration and (Unit)Testing, Hart Protocol, Profibus and Fieldbus Support for Embedded Systems and Windows Tools for Communication and Test |
Frequently Asked Questions
Q: Is there a special version available
as an update from HartDLL 6.0 to HartDLL 7.0?
A: No, HartDLL 7.0 is a new product. However, there will be updates
to the version 7.0 in future. The price of such an update depends on
the difference to the previous version. There is only one exception
for orders arriving before March 31st (see
QuotationHartDLL for further details).
Q: Is there any low cost Hart driver
available?
A: Yes, please refer to our products and look for Tiny Hart Tools.
Q: Can you send me a quotation?
A: Yes, but it is not necessary. For all our products you can
download a quotation from our site (Products).
Q: How many copies of the DLL may I
deliver with my application?
A: The number of run time copies is unlimited.
Q: How is the DLL registered at the
computer of the user getting my application? Du I have to provide
registry entries?
A: No, your application have to call the DLL when it is loaded. The
application has to pass the license code to the DLL.
Q: Does the DLL require any other
sources, components or DLLs?
A: No, all you need is this single DLL.
Q: Where do I have to install the
HartDLL if the application is delivered to the user?
A: There are two ways. You may copy it to the Windows system
directory or into the directory where your application is started.
Q: What exactly is usAddTimeOut?
A: In the Hart protocol specification a time out for the master
slave communication is defined. When the master has sent the last
byte of a request it starts a timer and waits for the response of
the slave. If certain amount of time expires before any byte from
the slave is received, the master assumes that the slave is not
responding. This TimeOut is specified with approximately 280 ms.
However, this is defining the interaction on the Hart Communication
wire. In real systems the situation may become different. If you are
using an usb modem, the usb driver in the PC may add an additional
delay. This means that even if the device is conform to the HART
specification the driver may not receive the response of the slave
in the 280 ms.
In the Hart protocol specification a time out for master slave communication is defined. When the master has sent the last byte of a request it starts a timer and waits for the response of the slave. If certain amount of time expires before any byte from the slave is received, the master assumes that the slave is not responding. This TimeOut is specified with approximately 280 ms. However, this is defining the interaction on the Hart Communication wire. In real systems the situation may become different. If you are using an usb modem, the usb driver in the PC may add an additional delay. This means that even if the device is conform to the HART specification the driver may not receive the response of the slave within the 280 ms.
Let's take an example. Assume that the usb modem is sending with no delay and adds 50 ms when receiving. If the slave would answer 275 ms after the master have sent the request the driver in the PC will receive the response after 325 ms because 50 ms were added by the usb driver. In this case the driver in the PC would raise an error because the response of the slave did not arrive in the time which was required.
To manage problems like this, usAddTimeOut was introduced in the HartDLL to extend the original time out by a certain amount of ms. When you are choosing 100 ms usAddTimeOut you are extending the Hart specification of 280 ms to 380 ms and the driver is working well with this modem.
FAQ
If you cannot find your question listed in this page please send us an email or just call. We are available for you at any time.