- #MODBUS POLL ILLEGAL DATA ADDRESS SERIAL#
- #MODBUS POLL ILLEGAL DATA ADDRESS SOFTWARE#
- #MODBUS POLL ILLEGAL DATA ADDRESS DOWNLOAD#
- #MODBUS POLL ILLEGAL DATA ADDRESS WINDOWS#
In a normal response, the slave echoes the function code. The slave replies with an exception response. The request is received without an error, but cannot be processed by the slave for another reason. The slave ignores the request and sends no response.Ĥ. The request is received by the slave with a parity, CRC or LRC error. The request is not received by the slave therefore no response is sent.ģ.
The request is successfully processed by the slave and a valid response is sent.Ģ.
#MODBUS POLL ILLEGAL DATA ADDRESS WINDOWS#
Beginning in 1990 with the release of Windows 3.0, ModScan has been around long enough to become the de-facto standard for maintenance of modbus networks the world over.ġ. ModScan is the original and still the best Windows application for testing and troubleshooting modbus devices. It can acquire data in integer, unsigned decimal, and floating point formats.
#MODBUS POLL ILLEGAL DATA ADDRESS SERIAL#
Modscan32 is a 32-bit Windows application (Modscan64 is similar, but for 64-bit Windows) that serves as a Modbus master device for protocol testing and performing Modbus serial and TCP/IP data collection by polling at user-defined intervals down to milliseconds.
#MODBUS POLL ILLEGAL DATA ADDRESS DOWNLOAD#
Modscan 64 Search and download modscan 64 open source project / source codes from. Demo mode allows sending and receiving six messages. All unlicensed programs run in demo mode. Home About MODBUS About Enron MODBUS Master Slave TCP Client Download Purchase Contact. If it is anything else other than this, then the modbus data is just wrong for some reason.Following a request, there are 4 possible outcomes from the slave. So the 2 modbus registers will be either 42F6 and E666 or E666 and 42F6. This allows us to see if the data from the meter is correct, correct but needing to be reversed, or just plain wrong.įor example if you set the meter value to 123.45, this decodes as 42F6E666 Hex. Then setup you modbus to read the "test" value only (2 modbus registers) and place these 2 registers into a DB as 2 words (not a real type). If, so we can use that as our test point instead. If you cannot fix a value, are there any values that ar quite steady? Is it possible for you to set one of the data points in the meter to a known fixed value? That way you might be able to spot what is going on by looking comparing the number you are decoding and the number in the Bently. You can convert real numbers to their hexadecimal equivalents and vice versa using these on-line calculators. If you are misplaced by one register you would get:.
It is possible that you might have got the address misplaced by one register such that you have the second half of one float number and the first half of the next float number.įor example take the 2 numbers 10.123 and 100.456 in sucessive values in the Bently. So if reversed, a very small change in the Bently number would result if a very large changed to the converted number. Is the value in the DB fluctuating by very large ammounts? This could be indicative of word reversal as the smaller half of the number varies a lot, and if reversed this becomes the larger half of the number, hence the large variations. 261.14956 is C3829325Hex and -2.61176eE+08 is CD7913C5 Hex, but this is not for certain, as the value may be changing by very large ammount (see below). Well it does not look as if the words are reversed as:.
#MODBUS POLL ILLEGAL DATA ADDRESS SOFTWARE#
Programming today is the race between software engineers building bigger and better idiot proof programs, and the universe producing bigger and better idiots. With 2) it is not possible, and you would have to see if the energy meter has the ability to word swap the data before it is sent (most comms interfaces that send real data have this option). With 1), it is very easy to change the order of the words that make up the dword to allow for this. This is because different computers / controllers can store the numbers in different ways (high-register / low-register or low-register / high register). You may need to swap over the registers for it to work. This will convert the two registers directly into a REAL value for you. Then take the two word values (registers), combine them into a DWORD using rotate / and operations, then convert the DWORD into a real.Ģ) Store the received data into a DB that has REAL type elements in it. What are the data types of the DB elements you are using to store the received data into?ġ) Store the data in a DB that has WORD type elements in it. These numbers are 32-bit in size and occupy two 16-bit modbus registers for each value. The energy meters data in in IEEE floating point (real) format.
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