Modbus protocol with resolution

[Guest Priti]

Sir, I have parameters for which resolution varies from 1 to 0.001 as per input type and resolution selected. if 1000 is transmitted, how to differentiate between 1000, 100.0, 10.00 and 1.000. Also all parameters are not resolution dependent, some are not resolution dependent, some are with fixed resolution and some are with variable resolution. How can be resolution data can be transfer along with parameter value. Even if current resolution is 1 but resolution dependent parameter can have resolution of 0.1. Kindly reply Regards, Priti

[Sleepy Wombat]

Priti, Please Register at MRPLC.com I am not 100% sure what you are asking but here goes.... The way i see it you have a slave modbus device that has a number of parmeters eg.. Volts, kW, Power Factor The modbus slave returns 2403, 0240, 0950 And you want to display 240.3V, 240kW and 0.95 Then your recieving device will have to manipulate the format into something useful. Modscan

[Guest Priti]

Thanks for the reply. My problem is the resolution is not fixed, it is defined at run time. Regards, Priti

[Guest Guest_Peter Nachtwey]

Why not send floating point?. We do the with Automation Direct PLCs and our motion controllers. A simple option if your application doesn't support floating point is to use the two words per location. The first is a number similar to the mantissa and the second is a exponent that indicates how many powers of two or ten you wish to shift left or right. In my applications where I don't have floating point I sometime use the latter option where the exponent words is used to shift the mantissa register left or right by powers of two.