Ethernet I/P to Yaskawa drives

[speakerman 4]

Hello everyone; We just installed and commissioned an Ethernet IP network to control 11 small Yaskawa VFD drives with an Allen Bradley 1756 controller. Thought I'd post the results, and offer help to anyone facing this challenge for the first time, as we just did. One short-term burp was not realizing the Yaskawa drives are defaulted to DHCP, which must be changed to 'fixed IP' after the proper addresses are installed. Once we had the proper IPs, the speed set to 100MBPS, and the address mode set to 'fixed', we rebooted the drives and the top green network light on the drive's Ethernet IP cards stopped flashing and the bottom lights started to flash. The top light is network detected, and the bottom is connection established. I proceeded to the Allen Bradley interface and started adding the generic Ethernet modules for each drive. The Yaskawa drives use two 16-bit words each for inputs and outputs in the IP comm, one with the binary interlocks and the other with the speed command in Hertz x 100. The manual I found showed a program example using a generic Ethernet module with a dim of two words for the I/O comm, but of course that had to be changed to 1, as the 1756 uses 32-bit tags. We used the interlock assemblies of 21 for outputs and 71 for inputs, and an RPI of 100ms. Each drive showed up configured immediately. I am very impressed with the ease of this comm setup. We multiply the speed command by 60, as the HMI speed controls were pre-configured in percent, and the drive interprets the command as an integer with two inferred decimal places. (100 percent x 60 = 6000, interpreted as 60.00 Hertz by the drive...). To make this work and put the 32-bit 'Real' speed command in the top two control word bytes, we move it from the real tag to a double integer. Then the double integer is word-swapped to move the speed command to the upper two bytes, and the individual bits of the lower control word are set over the next few rungs. The drives were configured for terminal strip control, and Ethernet IP allows the program to set two control word bits for Ethernet IP network to run the drive instead: bit 5 to take control of run/stop commands, and bit 6 to set the speed reference. I use the control bits to take over the drive when 'remote' is enabled. In local mode we leave the speed reference bit 6 enabled, but the run command comes from the local jog switch. One other burp that arose was the terminal strips for each drive had been wired with a fault that drove an input with the common leg of one of the panel lights. This caused the drives to lock up and not accept the comm speed reference. It was very odd, the drives would run at 33.3 hertz all the time, no matter what the command word was. Once we found the wiring fault and corrected it, the drives started to work perfectly. This was mode more difficult as the small drive's terminal strip is completely obscured by the Ethernet IP option card, and it has to be removed to change anything. Strange that a terminal strip wiring fault would cause the drive to lock up, but I think there is a note in the manual about not begin able to change the reference source during a run command. I think the terminal strip saw a permanent run command, which prevented our reference configuration changes from taking place. Just a theory. If anyone has questions about this, feel free to ask. i know some lead from someone who's gone through the process is always helpful. Happy programming, Speakerman.

[GT6Steve 4]

Thanx for the report, It's a keeper. I personally LOVE the Yaskawa's and have had great successes with them over the years. Sadly I have none in my current plant.

[a062549 5]

Nice write-ups! Maybe they should be saved in the Articles section. I like sticking wiht all AB, but today's market you may not get what you spec'd.