Babel Buster isn't talking, now what? (we are assuming Modbus RTU RS-485 here)
(1) Check the wiring web page to see that you have correctly wired the devices.
(2) Check the device tab to be sure you have selected the correct baud rate.
(3) Check to see that you have at least one read map defined. Holding register is most common type.
(4) Make sure response timeout is long enough (1 sec is ok during testing)
The red power light doubles as a status light used by Babel Buster SP software. If you have successfully configured Babel Buster to read at least one Modbus register, this light will be flashing. If off, recheck the web pages for missing configuration information.
If you think everything looks good so far, check the Error Codes page. The columns toward the right will show total message count and error counts. The most common problem will be finding a count in the "No Responses" column equal to the "Total Messages" (or within one). This means you are not communicating at all. A zero count, or count that never increases in the Total Messages column means it isn't trying - go back to checking the configuration. However, if Total Messages is counting upward, and No Responses is counting up just as fast, you have no communication between the devices even though Babel Buster is trying.
Reasons for no communications:
(a) Wiring problem. In addition to making sure plus goes to plus and minus to minus, make sure termination is turned on at the Babel Buster (DIP switch), and that you have termination at the other end of the line. You want termination only at the far end of the line, and not in any devices in the middle.
(b) Slave address, slave ID, or unit number (all names for same thing) not correct.
(c) Baud rate not correct.
(d) Response timeout too short for this device.
(e) Modbus device requires additional configuration before it will honor Modbus protocol.
(f) If device documentation only mentions "register" without reference to type, it is a holding register 99% of the time. But try "Input register" anyway if having no luck with holding register.
As long as you have at least one read map configured to try to read something, it is irrelevant whether the data is correct until Total Messages starts to exceed No Reponses by more than one.
If there is a long line between Babel Buster and the Modbus device that is not responding, temporarily move Babel Buster to within a few feet of the Modbus device and disconnect the rest of the RS-485 network. This test will rule out wire breaks, wire quality issues, termination questions, etc.
If you get a count in the "Exceptions" column, consider it progress. It means you are communicating, the devices are understanding each other, but the Modbus device is telling you something is invalid about your request. Asking for a register number that doesn't exist in the device is the most common cause of an exception error.
If you get CRC errors, wiring or baud rate mismatch are the most common cause.
