Posted 9 Nov 2017 Greetings everyone, I have a Proface HMI(LT-4201TM Modular type DIO) connected to a siemens flow transmitter(MAG6000). Communication between these two devices is using modbus. The modbus register that im using to get the data/reading of a totalizer from siemens transmitter are 403022 and 403023. I managed to display the exact totalizer value from siemens transmitter on the Proface HMI screen. But I couldnt get the exact totalizer value at the ladder logic side, the value that i get at the ladder logic side seems like a raw value. For an example, the totalizer's value is 147083(real value), but at the ladder logic side the value for 403022=15598 and 403023=17316. Can anyone guide me to solve this issue. Thanks in advance. Share this post Link to post Share on other sites
Posted 19 Dec 2017 A 32 bit floating point consists of four 8 bit bytes, each represented by two hexadecimal characters. The actual total value, 147082 (decimal) is 0x480fa2c0 in 32 bit floating point. the 1st byte is 0x48 the 2nd byte is 0x0F the 3rd byte is 0xA2 the 4th byte is 0xC0 The first byte value 0x48 makes a low 6 six digit value in the 100,000's in 32 bit floating point substituting a value 0x47 for the first byte reduces the total to well below 100,000, down to 37811. Although there are four accepted formats for floating point word and byte order and most common issue in getting the correct value is getting the words and bytes in the correct order, the problem here is that the value you provided from the ladder logic has no byte value close to 0x48 to get a 32 bit floating point total into the range of 100,000. Your ladder logic value is 15598 17316 decimal 15598 converted to hex = 0x3CEE 17316 converted to hex = 0x43A4 None of those bytes is close enough to 0x48 to get you a total over 100,000. In standard format, 0x3CEE43A4 = 0.029084988 Swapping word order gets the closest value: 0x43A43CEE = 328.476 Swapping bytes gets bizzare: 0x3CEE43A4 = 0.029084988 0xA443EE3C = -4.2485677E-17 Without a ladder logic value closer to what your actual total is, it's sheer speculation whether the issue is word/byte order. 1 person likes this Share this post Link to post Share on other sites