How to read input register over 65535 ?

[rhiesnand]

hi,

i have problem about read input register. i made program labview to monitoring Counter ( made by Autonics ),

my problem is when the counter is counting over 65534, suddenly on my program read 65535 = 1

for example

Autonics display | Labview display

65535                   | 1

65536                   | 2

65537                   | 3

65538                   | 4

etc

is that the maximum read input register ? or its a bug from modbus library ? i`ve changed the representation v16 to v64

any solution ? please help me  to read input register over 65535

thanks

[Dennis_Knutson]

Changing the indicator representation is a worthless step. You would have to change it internally. Are you sure about your device? I believe that the standard calls for 16 bit registers. You might need to read 2 registers. Please attach your manual.

p.s. It is U16 and U64, not V16 and V64.

[K C]

Through the ModBus protocol you can access 16bits registers. Not 8 , not 32 just 16 bits.

[crossrulz]

The Modbus standard is 16 bits.  So from a single register, 65535 is the highest you will be able to read.  If the counter uses a second register, you will need to read it as well and then use Join Number to make a 32 bit number.  If not, then you will need to keep track of the rollover and add 65536 to your number (I would expect 65536 = 0 in the register).