![]() There is, however, a variant of Modbus called Enron/Daniel that does use 4 bytes per Modbus register. The master is requesting 1 register, but the slave is returning data for 2 registers. The slave's response is not a valid Modbus response to the request. This is a case of a misleading error message being returned.Īccording to your attached packet captures, your master is sending the following request:Ġ1 03 00 0B 00 01 F5 C8 - Device 1, Read Holding Registers, Register Address 11, Number of Registers 1Ġ1 03 04 00 10 00 FB BA 75 - Device 1, Read Holding Registers, 4 data bytes, Data 0x001000FB ![]() I am hoping someone can help me correct this issue? The command sent from each of these applications looks the same. This is the same problem I am having when trying to use the PLC. You can see that only 2 of the four bytes were returned and there is a checksum error. Attached is a screen shot of the Modbus Poll Settings and the Serial Port Monitor after the command was sent. Then I tried using Modbus Poll software to read the same register. There were no problems using the Infinity software. ![]() Attached are screen captures of the Infinity and Serial Port Monitor. I am also using Serial Port Monitor software to see the commands being sent and received through the serial port. I started with the software that came with the meter, Infinity Configuration software, and used the modbus section of the software to send a read request to register HEX 0B (Dec 11). The MOXA is setup for RS485 two wire on port one (Com 1). ![]() ![]() I have a MOXA Uport usb serial device connected to my computer. So to verify I have meter settings and wiring correct I am using my PC to start with. My end goal is to use a PLC to communicate with this device, but I have have trouble getting that going. I am trying to set modbus RS485 2 wire communications with a Newport INF-B process meter. ![]()
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