Didro

Hello, We use the FX3U PLC and a several Modbus devices: six TesysU Schneider-Electric Contactors with LULC033 communication modules, FR-E700 and FR-F700 Mitsubishi Inverters. For PLC communication with devices by Modbus-RTU procotol we use FX3U-485ADP-MB module and RS2 command. As written in the datasheet LULC033 have 19200 bps transmission speed. AFAIK inverters' maximum transmission speed is 19200 bps too. The problem is too big delay in communication. We have to wait for a modbus device answer for 300 milliseconds. If we try to read the Modbus receive register early (for example with period euals 200-250 ms) - we see that there is no answer. What the standart answer time for Modbus device and does we achieve speed limit ? Thank you

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Thank you all for informative answers. I use GX Developer v 8.65 (not IEC). In D8001 I have - 0101111010110001 or in decimal - 24241, and if I'm understand you cleary, the firmware version of my PLC is 241. So it should work, but it doesn't. May be I do something wrong when try to check M8411 flag ? I connect FX3U-485ADP-MB module to PLC, connect it to ER-700 inverter's PU connector and then program in IL: LD M8411 SET Y0 And Y0 does't light up. Should I do something else ? >number device up 74..........(send me e-mail ) I don't understand what do you mean. I've sent you email.

Hello, I use FX3U PLC with FX3U-485ADP-MB module for Modbus RTU communitaion with inverter FR_E700 via RS485. I can read inverter params simply by RS2 command. But for use RS2 command I need to compute CRC manualy. In the same time FX3U and GXDev support ADPWR command, that itself computes CRC and do other nifty things greatly simplifed Modbus RTU communication. The cause by which I can't use ADPWR command is that in my PLC M8411 flag have never been set. In documentation (Modbus Serial Communication) I read, that M8411 flag is set by PLC when it ready for Modbus Communication. Should I do something special for work with FX3U-485ADP-MB via ADPRW ? Does somebody use ADPWR successfully ? Thank you

Hello All ! We use FX3U PLC and our customer wants to use UPS. When power supplier is down, PLC should sent message by GSM-modem. We plan to use simple APC Back-UPS (320VA). But our PLC has only one RS-232 port, and we already use it. Could we somehow connect UPS to PLC direct by PLC's input terminal? Thank you

Yet another question about Power Supply. I'd checked the manual for FX3U and for my external blocks (such as ADC\Termocouple and etc.), and after simple calculation I see that I overdraw the PLC's Service Supply. So I should to buy external power supply. The question is: Could I buy unipolar (24v and 0v) power supply block (such as MeanWell DR-120-24)? Or I must buy bipolar (24v\-24v\0v) ? I'm again confused by the image above. Thank you in advance!

Hello all, I've read the terminal layouts for FX2N-4AD-TC in its manual (FX2N-4AD-TC SPECIAL FUNCTION BLOCK USER’S GUIDE). (See the image below) Should I connect -24v of FX2N-4AD-TC to the 0 of FX3u PLC's built-in power supply ? Thank you

Hello, I've read in the FX3U-232-BD manual (FX COMMUNICATION (RS-232C, RS485)), that Maximum Baud Rate of FX3U-232-BD adapter is 19200 bit\sec. (See the image below) At the same time I could successfully connect with PC on the 115000 bit\sec. Is Maximum Baud Rate of FX3U-232-BD adapter is 19200 bit\sec ? Is it safe to exceed the 19200 bit\sec limit ? If I want to communicate with PC on the higher speed, should I use Ethernet module ? Thank you

Hello all, I'm beginner in PLC programming (but have some experience in PC programming, what might be not good in that case). I can't understand why the LD diagram on the picture below is forbidden ? (I use Russian version of GX, and the message box on the picture says, that "the LD diagram could not be transformed to IL code"). Might be it is GX Developer error ? I've been trying to find the rules of writing well formed LD diagrams, which I could transform to IL code and backwards. Thank you.