donny Posted March 21, 2015 Report Posted March 21, 2015 (edited) I am having difficulty displaying a number with exponent on a E-1101 HMI. I am able to read and display any Ana.signals without exponent using " Float without exponent". Have tried with "Float with exponent" but unable to display the actual value eg. 2.50 E-3 etc. HMI is connected to instrument via RS422 to RS422 ( Modbus protocol ) and all configured correctly as hmi could read all other parameters. Is there any method to read above without heavy calculations ? Any help is much appreciated. Thanks. Edited March 21, 2015 by donny Quote
Inntele Posted March 22, 2015 Report Posted March 22, 2015 donny, To give an answer, why you can not display the data, represented in format of floating point with exponent, we should know the format of data, that you are receiving from external device and would want to display. You did not give us this data yet. Quote
donny Posted March 23, 2015 Author Report Posted March 23, 2015 Inntele It is 32 bit real number and pressure reading from a Vacuum system. Instrument can display from 3.00E+1 to 9.99E-9. Have tried all possibilities but no result . I've heard that many HMIs can not display exponent without serious calculations. donny Quote
Inntele Posted March 23, 2015 Report Posted March 23, 2015 donny, As a standard, the exponential value can be represented in two forms of floating point: binary (usual) and scientific. In both case the value occupy two words. A good description in details was in FX1S-FX1N-FX2N Programming Manual. In scientific format the low word stores the mantissa part and the high word stores the exponential part, so there is no problem to represent the value at HMI as a combination of two INTEGERs. In a binary floating point format the mantissa occupies three least bytes, while the exponent occupy only a most byte... That's why I asked about "the format of data, that you are receiving from external device", because the value can be represented in first, second or even ... third format.... Once I met "inventors" from EU, who decided to represent the exponential value in a single word in equipment, they manufacture: a low byte is for mantissa part, a most byte is for exponent part... and they argued with me that their exponential form is a standard... A floating point binary format is an usual representation of floating point numbers in Mitsu PLCs, and the Beijer HMI should display it without problem... Quote
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