waynes

Easiest I know is to use the move instruction.    MOV K2M0 D0 This moves 2 nibbles (K2=2 nibbles=8 bits) starting at M0 to D0. 

Good day fellow PLC ninjas! I have a question/ concern which I would love your opinions on. We have 3 FX3U PLC’s+ENET cards. Two of the 3 PLC’s move around in an EMS trolley. The other is a ‘base station’ with a GOT2000 connected via Ethernet. Base PLC IP = 192.168.1.11 HMI IP = 192.168.1.31 Carrier 1 IP = 192.168.1.61 Carrier 2 IP = 192.168.1.62 I have programmed the base PLC to use Active communication; we are using fixed buffer communication to send and receive data to/ from the Carriers. The carriers are set up as Fullpassive ‘slaves’. This part works well and the update time changes (using a counter in the base station) from 1s to 100ms (because it enters a different work station).  My issue is the following: using a network sniffer (WireShark), I pick up plenty of re-transmits and sequence number errors coming from the base PLC’s ENET card. This is troublesome and causes delays when the update time is required to be fast (100ms). I am sending and receiving 10 words of data. The wifi seems stable, and there is minimal noise in the area. The power has been turned down and the antennas used are suited well for the application. The antennas are at a similar height to minimize possible loss of signal. I have LOS (line-of-sight) to the carriers at all times; to at least one of the antennas (I am using 802.11n). Has anyone picked up issues or found settings which can be used for comms over wifi? I can easily do this using a S7-1200 Siemens PLC and have done so using 12x S7-1200 clients and 2 AP’s with 1 base PLC. I have also successfully done this using 8xFX3U client with a System Q base PLC. My suspicion is that the delay in reading and writing to/ from the BFM in the ENET card is causing this. I am not sure that if I change to a FX5U will help. The communication cards on the Mitsubishi PLC’s seem very limited. Does anyone have any technical details on the access times between the CPU and communications cards’ BFM? Help is as always, appreciated.

Continuing with Gambit’s comment; are you using Profibus or some other fieldbus for the inputs? Local I/O should be fine, but you would need a DP2 file for Profibus devices as an example. Further to that, you will need to update the autorefresh for the I/O devices to get a cyclic update from the fieldbus.   

The project opens just fine with me. The CPU used is the Q13UDV. Have a look if your version supports this CPU. This project also has a PB92V card at IO 0x0080. I am using GX Works2 version 1.580E.  

Shubham, You should download the manuals for the products you are using and read through it first to get an understanding of how it works. As for the software, I believe that it is bought software and that it cannot be simply provided. All information provided by Gambit thus far is correct.  

Also do not use inputs X1 nor X2.

Unfortunately Mits isn't really good at using function blocks (this is of course in my own experience). You will find that you use much less memory/ steps if writing it in ladders/ steps, instead of FB's. The CPU you have chosen is too small (capacity size) and a larger CPU would be needed.

A long dead time is typical in process plants, but the incoming raw water wouldn't change too much inside a minute. I like the way of adding an offset and applying a weight to the SP, but would it not be easier to use the flow rate as a feed forward factor. In other words, tune it at a flow rate of x. Calculate the delta in flow rate and apply the change to the dosing pumps on the output of the PID, instead of the SP.

You can try Adroit. Pricing is fair and includes a 1 hour runtime demo.    www.adroit.co.za  

Hey Paolo, You are right that two characters (2 bytes) are stored in each D register (word - 16 bits). The remainder of the characters are stored in sequential D registers. Mitsubishi does not have 32 bit registers as far as I know. 

I love these little CPU's for their awesome instructions and the speed at which one can develop; but, when it comes to comms, it is a bit lacking.  We tested this situation with a FX5U and the issue went away. I assume that the bus between the cards is faster in the newer CPU's. It is a pity that you are disappointed with the FX5U; will have to do a few experiments myself first.

The one thing the configurator does do is to re-init the card after you changed the parameters. Try connecting from your VB.NET app and watch the error history inside the configurator. I think it is under the diagnostics button, error history. The error code will tell you what the exact issues is.  I have picked up issues on the FX3U and ENET cards and inspected it with Wireshark. This PLC does tend to make incorrect sequence numbers (in the header) and also re-transmits at times. I think it has to do with the PLC scan time and acyclic nature of the ENET card. Somewhere there is an issue, especially if the PLC has a longer scan time (>50ms) and there are multiple clients connected to it. As an example, I had the local support connect a PLC and GOT (HMI). They immediately saw the same results that I did. Try the FX5U; apparently it sorts most communication issues out. 

Thank you for the replies. We had a look at replacing the FX3U with the FX5U; but there is no stock available... Our time was limited so we decided to use an Omron 1-wire communication instead.  I have come to the conclusion that the Mitsubishi FX3U PLC simply is not designed to operate reliably over wifi or even fixed Ethernet. It is disappointing to see this as I have been a huge Mitsubishi fan for a very long time.

This instruction, together with index registers, makes for very exciting coding possibilities.

All the -/- does is invert the output of the logic preceding it. It is well documented in the PLC programming manuals.

Thank you. Now you could use special relays SM53/SM402/SM403 to create a little program to set the preset value (BFM #0,1 for CH1 and BFM #20,21 for CH2) to the last encoder value before the power failure. The manual contains the detail on how to set the preset encoder value (Chapter 5.4).

First off, I would use the Latch 2 range. Now, how do you get the encoder value? Dicrete Input(s) Profibus or other fieldbus High speed input card Let us know and we will advise you from there. How it will basically work is that you will write code to keep a copy of the last valid value of the encoder. If a power failure occurs, or an emergency stop is pressed, the new value from the encoder is ignored and restored to the last valid value (which is stored in a register).

Hey guys, I like the general idea of Melsoft Navigator, but I don't like the idea of re-creating projects with I/O modules, network modules, etc. Is there no simpler way to import the existing projects' I/O and network settings? Also, I've got an issue that GX Configurator DP doesn't yet integrate into the Navigator software. This is one of the most common fieldbus systems we use. Things like the batch read/ write is really awesome. I can "backup" all my PLC's with a few clicks. Crossbow, I don't know the extent of your connection with Mits, but could you please forward a request to support legacy devices like the CC-link module for the FX2N. (FX2N-32-CCL if memory serves) I've currently got version 1.83 - hopefully a few little bugs I've picked up will be delt with in the upcoming release. As we all know, software is continuously updated and with upgrades you can introduce bugs.

Hi guys, I have a FX3U PLC with a FX3U-ENET-L card connected to it. The system runs ok and does what it needs to. I am attempting to add another FX3U-ENET card to the right of the PLC. For some reason, as soon as I install and plug in the FX3U-ENET card, and then power up the PLC, it goes into fault/ error. Checking on PLC Diagnostics, the error code is 6107 PLC H/W ERROR. Has anyone ever experienced this? I want to make sure its not a software/ setup issue.

kaare_t, Thank you for your reply. I will get the local guys to swap the PLC's out as I bought it 2 weeks ago with the ENET-ADP cards.

Hi Gents, I've now got an issue where we replaced all the FX2N PLC's with their new FX3U counterparts. All the logic seems fine now, but we've added the FX3U-ENET-ADP modules. The problem is, I cannot set the parameters in GX Works2. I've got the ENET configurator software installed, selected the correct channel, but it doesn't even see the firmware version in the special registers (D8101, D8001 - if I recall correctly). According to the manual, JY997D45801-B, the CPU version needs to be 3.10. I have 3.01. 1) Is this information factually correct? 2) Is there a way to upgrade the CPU firmware?

Hi guys, Thanks for the info thus far. Currently looking into the link provided by Crossbow. I usually save the project with the name, date and a revision letter, something like CASCAM 20120617a. Any further mods for the day, major ones, I would just change the revision letter one up, let's say to b, and so forth. I have seen some systems at BMW, but they use Siemens S7. Looking for something that will help Mitsubishi out a bit.

Hey guys, As more and more PLC's are being installed and modified by more and more people, its often difficult to keep up with the latest PLC code and who modified what and why. Does anyone have any PC software that will take care of comparing a backup of a PLC to what's currently in the PLC and keep track of what was changed, and by whom?

I can totally agree with you on this one. Driver bugs and no real support to sort it out. I had an issue with the E1151 trying to communicate via Profibus DP. It took months to get a response out of the local suppliers. After getting the run around for another 6 months, I decided to throw my toys out of the cot. No solution was found but they offered to install a QJ71E71 (Ethernet) card and the network cables. I don't know where these guys are going with their brand. Totally disappointed.

Yeah of course Crossbow, that is another way to do it. I just didn't mention it as it would 'complicate' it a little bit for the user. He would have to use instructions like FLT and INT and so forth. What we typically do is to define exclusive states per machine, namely: Cycling: Set when the machine is in production Starved: Set when machine cycle cannot continue due to part at discharge Blocked: Set when no part present at infeed, and machine cannot continue Waiting Aux Part: Set when parts are not available at auxiliary part load station Waiting attention: Set when machine enters a 'fault state' Repair in progress Emergency stop Bypass Selected Tool change Shutdown Setup Mode Break No comms Using each one of the above exclusive states, the total running/ monitoring time can then be calculated. Each of the states would be a percentage of the total running time and you can monitor your total uptime in hours and minutes or as a percentage. If you do it this way you will really get down to the actual reasons why there might be possible production loss or inefficiencies, and where the stem from. Best of luck!