Ivan Ristic

Hello. Yes, fan is at the bottom right and exhaust filter is top left. Fan is pushing air into the cabinet. Regarding cleaning of filters, I am not sure how often they will clean it (probably once every 5 years as usual). I agree with you about the dust. I like clean cabinets without dust and spaghetti wires. Thank you all for help. Best regards. Ivan

Hello. There is no heat exchanger. I install fan on the cabinet controlled by thermostat. Also, there is one more thermostat connected to PLC input to trigger alarm if there is over temperature in the cabinet. I could record temperature as you proposed and "see" inside conditions in the cabinet. Thank you for suggestion. Best regards. Ivan

Hello. I finally fixed problem. Yesterday and today, I rerouted power and control wires so now all high voltage/current wires go on the left side and control wires goes on the right side. Also, I connect all common ground wires to one point on the bottom of cabinet as proposed by @kratmel and @DanT. I tested all 10 VFD running at the same time for almost one hour and communication with IO modules is perfect, without any single error (blink) of status LED. Thank you all for helping me solve the problem. You are great. Best regards. Ivan

Thank you for help. I will reroute IO modules "FG" wires tomorrow and test. I also use left side channel for most VFD power wires but there is couple of drives supplied from the right side channel. Signal and control wires are in the right channel but there is also in the left. I mixed them because of space which probably make problem with noise coupling. I will try to separate them as much as possible and see if this fix the problem. Regarding ferrite beads (rings), maybe this can help but I can not get them soon. I could also try to install metal plate between drives and upper part with IO modules as proposed by @Gabriel Franco just I am not sure how to install it? At the end, I could change switching frequency of the drives. Now is 8 KHz if I remember correctly. I can put it to 6 or 4 KHz if this could help? Tommorow I will test this things and see what happens. Thank you again for help.

Hello. Sorry for late answer. @kratmel I did test connecting 0V to ground but same problem. I try to separate FG connection of all IO modules from ground and then it was better. Still losing communication but less frequent. I have also cable for Modbus communication between all 10 VFD. I forget to mention this. When I disconnect cable from RS485 connector on the CPU module then it works. Still from time to time lose connection to IO modules but it's much better. It looks like problem with ground loops together with noise from the drives. All 10 VFD are in the same cabinet. This is first project with this number of drives that I used. I have picture while the wiring was still not finished. Control wires to VFD are mixed with power lines. Motor cables are shielded, and shield is connected on both sides with ground. Cables go behind back plate through holes, so they are at least not close to other wires. I will try to separate them as much as possible, but problem is that I must finish all till the end of the week. All VFD ground points are connected to common ground on the bottom of the cabinet. Maybe I could try metal plate proposal to separate VFD from PLC IO modules. One thing that I could do is to move all IO modules and install them on the back of Unitronics panel and extend wires from old position to panel on the door, but I am not sure is this going to help or make more problems because of longer wires?

Hello again. I just upgraded firmware for all (CPU, IO, FPGA and panel) but problem is still present. When I select 6 or more VFD devices for running, the moment I start motors, all IO module lamps start randomly flashing between green and red and there is message on the screen which I attached in first post.

Hello Mr. Alex. Thank you for your help. I am right now at the site and will try to do upgrade. Since this is first time with Unistream devices I need just short explanation. I packed project file together with firmware on the flash drive. Drive is in the panel. Should I upgrade all (panel, IO, CPU and UserApp) or just IO Units? Here is a screenshot of upgrade menu: Thank you.

Hello. In my latest project I use USP-104-B10 panel with USC-P-B10 CPU mounted on the cabinet door. IO modules are installed on the back plane in the same cabinet connected with UAG-XK300 extension kit. PLC is controlling speed of 10 VFD devices with analog voltage outputs UIA-0006. I have problem with I/O bus error message showing when I run more than 6 VFD in the same time. Single drives are working correctly but when I switch on more then 6 or 7 drives I get error message and system continue working for couple of second and then communication with IO's is lost. After that, I must switch off power supply for all modules and HMI also to continue. I suspect problem is some noise from VFD while running. I try to move cable from expansion kit as far as possible from the VFD and power cables but without success. Also, all motor cables are shielded and shield connected to ground wire on both sides (motor and VFD). All IO modules have ground point connected to common ground (PE). Analog outputs are connected directly to VFD analog inputs and 24 volts common is connected to common input on VFD. I know that analog output module is not isolated but there is no other way. I need help because I get to the point where I don't know what to do to fix this problem and I must finish this project in couple of days. Thank you.

Hello. This is my first post to this forum. I've been using Unitronics PLC for couple of the projects in the past and now I need help regarding hardware connection of analog output module. Currently I am just planning for the next project, so I don't have any hardware yet. I need to control the speed of 10 frequency drives so idea is to use two analog output modules UIA-0006 configured as 0-10V. Common point of analog inputs on all VFD's will be connected to 0V system power supply. This power supply will be used also to provide power for all IO modules in the system and PLC with HMI itself. Question is do I need to connect common ground (CM0, CM1, CM2, CM3, CM4 and CM5) to system 0V or leave it unconnected and just use voltage outputs (O0V, O1V . . .) connected to VFD analog input? I am asking this because in the manual it says that analog outputs are not isolated, so I assume that internally all common points are connected to 0V power terminal. In the manual for UIA-0006 there is also two sentences which are not clear to me: Individually connect each 0V point and each common (CM) point in the system to the power supply 0V terminal, unless otherwise specified (page 5). Do not connect the common point (CM) to the 0V point (page 6). Is there any risk of damaging UIA-0006 with this connection? Even if I disconnect common points on VFD's they will probably still be connected through analog output module because outputs are not isolated. Thank you for help.