JRoss

I have a customer with a Panelmate Pro they want to backup. I can't find any information about these on the Eaton website. What software and cable do I need? I unfortunately don't have a model number yet, but can probably get one if it matters. Thanks

I'm working on a waste water application where I need to control three pumps with outputs attached to a single header, and maintain a flow at the output of the header. Attached is my napkin sketch of the system. Generally, only pumps 1 and 3 are used, with pump 2 as a backup. Right now, they run in manual only, setting both pumps to the same speed to maintain the correct flow at the output of the common header. I'm doing the programming to add the automatic function. I have the four flowmeters as analog inputs. At this time, the valves are all manually actuated, but a later phase of the project will automate the valves, and allow the backup pump to come online if either of the main pumps fails. My question is how to handle the PID. Should I do a single PID using Flowmeter 4 as the PV, and run both active pumps at the same speed, similar to the current manual process? Or should I give each pump its own PID off its own flowmeter, then use a master PID off Flowmeter 4 to control the setpoint of the active pumps? I'm inclined to go with the simple approach, but am open to suggestions from the forum. Thanks,

If you haven't done this already... Apply to jobs even if you don't meet all the requirements. A lot of times the job requirements are "nice to have" not "need to have". All things being equal, an employer will take someone with the two years experience over someone without. But if they can't find candidates who meet the full set of requirements and if you impress them enough during the interview process, they may give you a chance anyway. I don't know what the situation is in the UK, but here in the US it's very tough to find qualified controls engineers, which is a good opportunity for people like yourself.

Is the logic for the encoder in the main continuous scan task of the PLC? If so move it to a periodic task with a small execution time. If the logic is small enough, make this 1ms. What are the windows you're trying to capture?

That works too. I decided to just create a new global label file just for alarms and generated the list in Excel and copied it in.

I was just searching for this feature, though I'm using GX Works 3. Not sure if there's been any change, but so far I can't find it. Here's why I want to do this. I created a global array of bits for alarms, and was hoping to add a comment to each bit in the array to describe what that particular alarm is for. I supposed I can create individual alarm bits and then just make sure they're in a contiguous memory area, but I thought this would be easier.

I usually use not equal to 0. You might be all right because you're using 5 nibbles, but if you use 4 (INT) or 8 (DINT), then the most significant bit acts like a sign bit, which means if it's on the value of the grouped bits will be negative.

+1 on the PCIS software. I've used it in both a Win3.1 virtual machine and in a WinXP virtual machine. If you can get your hands on an older laptop with WinXP and a serial port, that'll be easier than messing with an emulator or virtual machine. Note you will need the serial cable adapter for it. Edit: You will still have to hand-convert the code. It won't automatically convert to RSLogix 500.

At some point in the past you must have gone into Online Monitor/Write mode to make online changes. This sets an option to write changes to the PLC after compiling. Go to Tools/Options and look for that setting.

bump

Has anyone used the A800 with encoder card as a standalone motion axis? I'm looking at upgrading some Danfoss drives with SyncPos motion cards for a customer. I can go full bore and replace the drives and motors with servos, or I could attempt to just replace the drives and leave the original motors and encoders for about half the cost.

Huh, for some reason emails from MrPLC started going into my spam folder, and I just found this. The programs in the motion card are pretty basic. Jog forward and reverse. Homing with some variation based on direction and location of the home sensor. Absolute positioning to fixed positions. One of the drives switches to torque mode for a period of time to seat a mold in place

What version of GX Developer are you using? You have to be at a recent enough version for the FX3S. I recommend upgrading to GX Works 2.

As far as I know, those are the only three options.

Unless you're talking a really slow pulse train, you will either need to get a transistor base unit, or an FX3U-1PG special function module. Only the first three outputs of a transistor base unit will work with the high-speed commands like PLSY, DRVI, and DRVA. The FX3U-1PG uses standard FROM/TO commands to set up and execute the motion. Using the built-in commands with the base unit is much easier, so I would highly recommend replacing the base unit.

I have a customer with two machines that have TSX17 PLCs on them. I need to back up the programs and eventually convert them to a newer PLC. What programming cable and software do I need? Machine 1 has the following: TSX17 F4002TSXDTF400Machine 2 has the following: TSX17 F4002TSXDSF612Thanks!

Take a look at the help file. When you select the type and temp units on the configuration tab of the module properties, it scales to the published range of the thermocouple, and the value you get is the temperature. The 0-7000 you see is grayed out and doesn't apply unless you choose "custom range" instead of Celsius or Farenheit. So if you have the thermocouple in ice water, you should see 32F or 0C depending on the units. If you don't, then there is a problem with the thermocouple, the card, or the wiring. Either that or you have a different type than you think.

Yes, configure your card as Joe E states, then you'll get the actual temp reading in your input data. Then you can just use comparison intructions (LES, GRT, LEQ, GEQ) for off-on control of your heaters.

Not without knowing what you are trying to accomplish. What is the process? Give as much detail as you are legally allowed!

Well... An RTD and a thermocouple are both temperature sensors. Choosing one versus the other is a factor of the temperature range, accuracy, and the characteristics of what you are monitoring. But both give you the same piece of information. So you can change the type, but the PLC won't do anything differently. Next, an SCP isn't a control algorithm, it's a scaling instruction. It's for taking one linear range of numbers (like 4-20mA) and converting to another (like 0-1000 degrees). It sounds like you want a PID instruction.

Once you install the AOI, you can use it in the ladder logic as if it were a regular instruction. In ladder, add an instruction and type in the name of the AOI, in this case it should be "SCP". You'll see the block appear with 7 arguments. The first is for a tag with a custom data type to match the AOI. I usually type in a name like "DeviceID_SCP", then right-click and create a tag on the spot. You shouldn't need to do anything in the create tag dialog except click OK. Then back in the ladder, you can enter the tags or constants for the rest of the arguments, just like in RS Logix 500.

I got the AOI from a colleague, but I suspect he got it from Rockwell. I've tweaked it a little, but the guts are essentially the same. I modified it so that I don't have to assign separate tags for the min/max parameters and added an "In Range" bit. I'm also planning to add a clamping feature in a week or so.

Maybe try to download it to a PLC, then create a new project without labels and upload the PLC.

There isn't a built-in scaling instruction in Logix 5000. You can use the CPT (compute) function and put the computation in that way. I use an SCP add-on instruction (AOI) that I got from a colleague years ago and have modified slightly. It mimics the operation of the SCP in Logix 500 and is much easier to use. It's basically the CPT function hidden inside an AOI with a couple of other features, but I like it. PM me your email address and I'll send it to you.

I think the only difference is that in jog mode you don't have control over the speed using digital inputs or analog input. I would use speed control mode in your application for that reason.