wonder ware modbus tcp

[RY_Guthrie]

I am using ww ver. 10.1 sp3 rrunning dasmbtcp to poll a total flow, I have one address that is giving me fits, everytime I try to use it in a tag it turns red in my device diagnostics, I have attached a screen shot of the error I am getting, it says bad configuration but for the life of me I cant see what I have configured wrong.

 

[diat150]

can you post a screenshot of the totalflow modbus map configuration?

 

[RY_Guthrie]

unfortunately no I can't, I was just given the modbus register address and I set up the smc to poll them, All the others work and the engineer I am talking to that sent me the modbus address says he can see the data from this register. the modbus address is 47045 floating point.

 

[diat150]

in that case I would try something like modbus poll to verify that it isnt an issue with the wonderware setup.

 

[RY_Guthrie]

ok I will see if I can figure out how to go about doing that.

 

[Bit_Bucket_07]

Are you sure that 47045 is actually set up as a floating point reference in the PLC and that register 47046 is not also being used in the PLC program?

 

[RY_Guthrie]

its actually in a total flow not a plc, and I can not look at the registers, but I was told by an engineer at a remote location that he can read the data and the numbers he is telling my look pretty close to what the total flow is saying on its screen. I learning how to use modbus poll to see if its wonder ware problem or a total flow problem.

 

[diat150]

what point is this in the totalflow? like atemperature or pressure?

 

[RY_Guthrie]

actually it is a flow measurement, differential pressure.

 

[diat150]

actually it is a flow measurement, differential pressure.

yeah I am very familiar with totalflows, as I have probably communicated to well over 1000 of them in the last few years. maybe if you could get the guy to send you the config file and post it here I can take a look. outside of that or a screenshot about the only thing I could recommend is trying modbus poll. if the pressure, flowrate, temp, yesterdays volume are all working right it has to be something on his end. maybe he didnt key in the right address when setting up the modbus map. it shouldnt be pretty close, it should be spot on.

 

[danw]

Floating point has several different word and byte order formats, sometimes known as Big Endian or Little Endian formats.

Floating point is a mantissa and an exponent, so if you read a floating point value (in Modbus a 32 bit floating point value is 2 Modbus registers of 16 bits each) and the word or byte order is not correct, the Modbus master's interpretation of the value is really bizarre, frequently a value with a very high exponent, like 22nd power. Sometimes the value is so bizarre that master might even consider it nan - not a number.

An extreme value might very well trigger an out-of-range error.

It would be worth exploring which format the slave is and which format the master is using to interpret the value.

Or just changing formats to see if the interpretation suddenly makes sense, which is why I like the generic PC Modbus masters like Modscan32 - it's really easy to change formats with the click of a button.