Colin Carpenter

There's a software example of setting up a A1S68AD in this thread http://forums.mrplc.com/index.php?showtopic=7677 Should be pretty self explanatory.

Yes, that was a really good post. I'd never realised that 4 bits was called a nibble before, and it was only when I looked it up that I realised that a nibble "corresponds to a single hexadecimal digit". All makes more sense as the light bulbs start to go on .....

Doesn't the PanelView allow you to scale the analogue directly in it's own software? Have never used a PanelView, but always the use a Beijers E-Terminal. In these, you can enter two pairs of points, namely: E-Terminal = 0 and 100 PLC = 0 and 32767 The software in the E-Terminal then works out the "y=mx+c" equation and automatically sends the correct value to the PLC ( ie 0-100% = 0-32767bits). It's so good that I rarely bother to do scaling in the PLC, just do it on the E-Terminal screens and the answer goes straight to the PLC. Saves a lot of programming. I was forced to use another brand HMI once, and just couldn't believe that this function wasn't available in the HMI. Surely a PanelView can do it? Tell me it ain't so, Joe.

Hi Gary, Can you confirm which of the 3 wiring methods shown in the manual that you use in your cable? I've attached the three options in the graphic below .... currently I've got the cable made up as shown in option B, because I have no idea if a laptop serial port is capable of turning on or off a CD signal. I chose this option after reading Panic Mode's post in one of the other threads. Cable seems to "sort of" work .... light flashes on the UC24, then other lights come on, but no real comms. Cheers.

Hi Gary, If you get the darn thing working, I'd like to know how you did it. I've been scratching my head trying to get a UC24 to act as a second programming port on an A1S system (the CPU port will be taken up by a Mac screen which is too far away from the PLC for me to transparently talk through the MAc via serial). The only cards I've used for SCADA acces have been the RS485 versions, which tend to be easier as the RS232 lead and connections is sorted out in the RS232 - RS485 converter, and from there onwards, the wiring is much simpler. The manuals for the UC24 set a new standard in lack of information in my humble opinion........ five protocols, but not a single word on what each one is used for

Can anyone tell me if it's OK / advised to insert rungs in "online mode" into an RS Logix 500 programme? Reason I ask is this: System is a large(ish) SLC 500/5 system with 3 PLCs sharing information by Ethernet through a switch. Needed to insert a couple of rungs into one of the PLCs while "online". All seemed to go OK, no fault lights, no error messages .....UNTIL The PLC that had received the two rungs stopped communicating by Ethernet and all hell broke loose, with the other two running into problems. Much panicking and head scratching revealed that the rung that called the Comms Ladder (SBR) had become deleted in the MAIN Ladder, so the Comms part of the software was not operational.This rung would have been Rung 3 in the entire Programme. Re-loaded the backup code and all is now well. So, it seems like inserting two rungs way down in the programme caused deletion of at least one rung at the top of the programme. It definitely wasn't a human deletion, as there were two of us, each checking the other's actions. Did we try and do something that's not possible or something that just shouldn't be attempted?

Now here's a funny thing. Last November, we built and installed a plant that used two control valves wired in series to one analogue output (4-20 mA). The valves have Samson controllers with LCD displays that are self powered by the 4-20 mA signal so that you can see on the displays the "valve open" percentage. One valve closes as the other valve opens, so we were controlling the flow of a product by this means. All worked perfectly, the valves opened and closed as commanded, and the 4-20mA from the PLC would cause the valves to go from fully open to fully closed. Today, I was asked to look at the plant as the "forward valve" was not closing completely. Sure enough, it was stopping at a 25% open point. Checked the PLC and 1000 bits was being applied to the analogue output, which equates to 20 mA on an FX2N-4DA output channel. Tested the mA flowing and found it to be about 15 mA. So I suspected the analogue output, disconnected the valves and ran the current through a MA tester - 20 mA flowing. Replaced the valves - back to 15 mA. Shorted out one of the valves and 20 mA flowed, shorted out the other valve and 20 mA flowed. Now I'm starting to suspect a high impedance, so used Ohm's Law and voltage drop across the valve terminals to work out that the impedance of each valve is around 500 ohms, giving a total impedance of around 1000 ohms. Check the manual for the FX2N-4DA and find that the maximum impedance the channel can cope with is 500 ohms. So, based on the assumption that it's unlikely that both valves have significantly increased their respective impedances, how has this ever worked in the past, given that the current total impedance is about twice the maximum that the channel can supply? I'm confused .........

As a follow up, I did check the voltage of the PSU, and it had dropped to about 22.5 volts, so wound it up to about 26 volts, but with no improvement in the situation, so it back to 25 volts DC. Conclusion is that, for some reason, the impedance of the valves has increased above what it should be, and the combined (series) load is now greater than the PLC analogue output can "drive" into. Solution was to fit a milliamp re-transmitter which can drive into a higher impedance value than the PLC analogue output. All works fine now.

Have never used a GSM modem with Mitsubishi kit, but I do know that Mitsubishi had a lot of problems with their ordinary modems in the UK and now specify using Westermo modems, which are very good, rock solid and with excellent tech support. I think there's quite a few quirks which may catch you out when using modems with Mitsubishi equipment ......

Ah, that explains the advertising links then ....... I did see the thread and printed off the graphic, made sure I wired the comms cable exactly as you detailed, but still can't get any comms to work. There is a strange reference to CD capable devices in the manual for the UC24, (pin 1 on a 9 pin RS232) which seems to indicate that a bit of software needs to be written if pin 1 is not used, so I tried that and still got nowhere. Wish I knew what the protocols 1-5 meant and which one to use ..... you'd think they might tell us. Tech support in the UK involves phoning a woman at Mitsubishi who then writes down your number and takes it round to one of the techies, who might (repeat might) phone you back if there's an "R" in the month, the phase of the moon is right and it's a Leap Year. There are a couple of good guys who work for the distributors, but they're hard to get hold of as everyone wants to talk to them ...... Ah, well, at least it makes it interesting.

I'd like to use an A1SJ71UC24-R2 as a second programming port for a Q2AS plc. I've wired it all up, soldered up the comms cable, set the dip switches but can't get comms. I'm pretty sure that the reason is that IEC Developer V7 only gives me the option of using an A2SJ71QC24-R2, which I think may be different. Has anyone managed to do the above, or am I wasting my time? Thanks.

Thanks for that .... it looks like it is an IEC Developer issue, although it's a bit scary when you realise that Mitsubishi brought out an A1SJ71QC24-R2, which, when you download the manual, only refers to the QnA range of PLCs .... makes you think that there may be some issues between UC24 and the Q2AS. Incidentally, just to prove a point to myself, I installed the UC24 in a rack with an A1S-S1 and can't even get that to talk through IEC Developer. Reckon that the manuals for the UC24 are about the worst I've ever seen for a Mitsubishi product. The simple one gives clues without going into detail, and the larger only seems to talk about Modbus and other exotica. All I want to do is talk to one Mitsubishi product from another Mitsubishi product using a third Mitsubishi product...... you'd think the manuals would specify how to do the simple things before the difficult things, but I'm afraid not Incidentally, why has the forum started inserting advertising links in posts that I just don't want to be there?

You could try this .... simplifies the code a bit. Tip ..... always use a PLS instruction to SET and RST flags. You don't have to, but it solves a lot of headaches. Haven't tested it, but I think it will work. Sets M0 at first instance of X0 closing. LD X0 PLS M100 LD M100 SET M0 Multiple cascading timers First 3 sec wait LD M0 OUT T0 K30 First 7 sec wait LD T0 OUT T1 K70 Second 3 sec wait LD T1 OUT T2 K30 Second 7 sec wait LD T2 OUT T3 K70 Third 3 sec wait LD T3 OUT T4 K30 Third 7 sec Wait LD T4 OUT T5 K70 Output Control - in each case, output comes ON when preceding 3 sec timer has timed out, for as long as it's own 7 second timer LD M0 AND T0 ANI T1 OUT Y0 LD M0 AND T2 ANI T3 OUT Y1 LD M0 AND T4 ANI T5 OUT Y2 Resets the sequence at end of Timer T5 Will restart when X0 ON again. LD T5 PLS M101 LD M101 RST M0

Thanks ...... that's interesting, I'll do that and will check if the 24VDC power supply has a "tweak button" on it. I hadn't realised that PSU voltage had an affect on the load that the analogue output could drive into.

IEC Developer allows you to compare accumulator values directly. Using IEC there are three "parts" to a standard timer: TC0 = Timer Coil of T0 TS0 = Timer Switch of T0 (closes when timer times out) TN0 = Accumulated timer value of T0. Therefore, you could use an expression like if TN0 >= 20 (assuming 100ms timers) then do something.

Sorry, can't help. Have never needed to or wanted to programme in SFC. Stepladder (STL) no probelm, but not SFC

We have something called the Data Station Plus now, which is like the Babel Box on steroids. Wow, that looks an awesome piece of kit .... will definitely keep that in mind for future jobs. Shame you changed the name, though .... "Babel Box" just had so much more "mystique" than Data Station Plus

Have never actually done it, but they tell me that the range of Beijers E-Terminals can act as converters to allow Mitsubishi to talk to Allen Bradley and vice versa. You can assign two PLCs to each HMI and translate accordingly ...... they tell me. Another option is to look up the Babel Box which I believe is made by Red Lion Controls with protocol conversion in mind. I would think that you're gonna have to go with a "third party" supplier on this one, as I imagine "Allen Bradley" is a swear word at Mitsubishi and vice versa

Has anyone at Mitsubishi Tech Support been able to tell you exactly what "share memory" is and what it is used for? I tried and tried and have yet to come across anyone who actually knows .............. Google seems to think that usually it's memory shared between multiple processors, but I'm sure that's not what it is in this case.

The question I would like answered is "What exactly is share memory?" I accept that upgrading the ram may "cure" the problem, but on a laptop that shows 300 Mb of spare memory (when all is loaded up and working), how much more does IEC need to work on a file that is about 3 Mb in size? Also, when it locks up on me, I close IEC, then restart it, I get the message "Cannot allocate share memory" ..... but it still works, so if it can't allocate share memory, what memory is it now using to work with? And if it quite happily works when it can't allocate share memory, what does it need share memory for in the first place? Almost get the impression that the error message is not actually related to memory at all ........ just happens to use that error message when it can't think of anything else.

I'm using a Panasonic Toughbook with 512 MB and dedicated graphics card, running XP Pro and I'm pretty sure that the "Cannot allocate share memory" message when checking a POU is caused by a bug in IEC Developer. Whenever it arises, everything else is fine, the PC still operates fine, it just says that IEC Developer has "stopped responding". Have contacted Mitsubishi (limited help) and have failed to find any mention anywhere about what "share memory" actually is ...... XP doesn't seem to know and nor do the Mitsubishi support guys. Anyone know?

Try this link, not sure exactly how it works, but it seems that it makes your ISP invisible. http://securebar.secure-tunnel.com/cgi-bin.../main/Home/home The full address is shown below in double brackets ((http://securebar.secure-tunnel.com/cgi-bin/nph-freebar.cgi/110110A/http/www.meau.com/eprise/main/Home/home))

5. Oops... I'm sorry, I didn't catch the idea about HEX addresses... I think that may be what's causing your problem. You HAVE TO know the Hex address of the various cards to be able to write the software to read from the Buffer Memories. If you don't then strange things are going to happen...... I've added a Gif file of a 68AD set up in IEC Developer, the commands are the same regardless of what software you are using. Note the way that values are read from buffer memories of the special function cards residing at the Hex address of the card. You do need to know this, unless I'm missing something pretty fundamental

I have no idea what Shared Memory is in the Melsec World, but it often gives me a problem in IEC Developer. When some changes have been made in a POU, clicking on the "test POU" icon will often cause the application to "hang", requiring a CTR ALT DEL to stop the application. Luckily, it always recovers the file OK, but when re-starting IEC Developer, I get the message "Unable to allocate shared memory" ..... but it seems to work OK. Only way to get rid of this message and get a normal start, is to re-boot. This has done this on every version of IEC (up to 7.2) and previous versions of MM Plus, on loads of different PCs and every operating system I've tried (NT, 98, XP Pro). Strangely I don't get the error if I "build" the project, rather than "test" the POU, so that's what I now tend to do. Problem is that the "test POU" command is a key part of online modifications, which is great when IEC "hangs" halfway through an online mod. Now, how far exactly did that operation get? ....... hmmmmm.

I may be wrong, but I doubt that there's a compatibility issue. Here's some things that I would check, (in no particular order). 1. Does the extension base have "-S1" at the end of it's part number? If it does, then there will be some jumpers underneath the plastic cover. Lift this off and check that the the jumper is across the first pair of pins .... can't remember if they are marked "1" or "0", but it will be the "top" pins. 2. The A1S68AD has to have dip switches set on it to configure each of the channels for whatever the analogue input is that you want to measure. Check that these are set to whatever you want to measure. 3. Personally, I don't like spare slots part way through a rack .... leave the spares at the end of the rack and avoid unknowns. 4. If you're using IEC Developer software, I've found that the later versions seem to insist that the IO configuration section is completed before compiling. Seems that if you don't tell the software the card is there, the PLC can't seem to see anything on the card. Seems strange, as it never seemed to be that way with the early versions, but there you go ...... 5. Be very careful that you have correctly worked out the HEX start and end addresses of each card. This is especially true with analogue cards where the "HEAD ADDRESS" needs to be entered in the software that determines where the buffer memories are to be read from. The HEAD ADDRESS is the two most significant digits, so for an analogue card starting at 0A0, the HEAD ADDRESS would be 0A (not A0). For a card starting at 1B0, the HEAD ADDRESS would be 1B. (I find it helps to add a leading 0 to all hex addresses below 100) 6. The A1S68DAI card will need to have it's output channels switched on in the software, by "OUT" Coils. These are determined by the address at which the card sits. So, if the 32 address card starts at 0A0 and ends at 0BF, then you would have to energise YB0 through to YB7 .... note that these addresses are "halfway" through the cards address range. These things can drive you mad ...... normally it's a mistake in the Hex addressing