rbyrne15

Is it possible to unlatch a latched coil in ProWorx 32? My program latches a coil upon completion of a timer, but I need to unlatch the coil on the activiation of an input. When the timer loses power at the input, the output de-energises, which is not suitable for my application, hence the use of a latcing coil. Thanks in advance, Richard Byrne.

Thanks to both of you for the replies. I like the look of the workaround quoted above. It's now stored in my brain's programming toolbox. Richard.

I was wondering whether someone could explain how to address the bit in the status word of a Momentum processor, which denotes that the PLC is in its first scan. In Allen Bradley, this bit has the addres "S:1/15" - but in the Modicon equipment I have no idea. Even better than an explanation would be a pointer to the relevant page in the help file. Thanks, Richard Byrne. (Soon to be Technologist)

Thanks for the reply - now I have another question. After playing around with our loaned PLC, an ADM 350 10 (M1 980-20 processor), I wrote a small program to the controller: ---|10001|---(00001)--- I forced the input condition on, and even applied 24Vdc to "pin 1" and "pin 16" (with the input re-enabled) on the control I/O terminal block, to find that output 1 didn't light. What am I doing wrong or missing? Thanks, Richard Byrne.

Hi Folks, I'm about to start a final year project, in which I plan to use a Momentum controller and a Magelis touchscreen interface to control a small process. I worked with the Magelis and the relevant software during this past summer - a sweet summer job that was... I wondered if anyone could nudge me in the direction of the Momentum instruction set. I'll be programming using NxT (ladder programs). I've searched the Telemecanique website several times, but nothing about instruction sets came up. The literature library that AB use is much better, but oh well. Thanks , Richard Byrne.

Thanks for the help Ken. I've not been able to progress on my project because of this problem. Hopefully we'll be flying again. Let me just make sure I understand what you're telling me... Once again in RSNetWorx I will open the 1747-SDN scanner module's properties list and remove the NET-DNI's entry from this list. Is there a way to disable it, instead of removing it totally? And by cycling power to the "slave device" do you mean the MicroLogix 1500 or the NET-DNI? Thanks for all help so far, Richard

Hi Everyone, I have a specific problem when trying to change the parameters on a DNI module used on my project's DeviceNet network. When I tried, earlier on today, to change the input/output file number and the input/output word offsets in the parameter list for that node, I received an error message: "Error occurred when communicating with device." (I was using RSNetWork for DeviceNet, and was not online when making the alterations and trying to download the new settings). I was trying to change parameter numbers 1, 2, 4, 5, 6, 7, 9 and 10. The previous (factory-programmed) input file number for the equipment was N20. I need it to be N60. I realise that my series B DNI requires the number of input/output words to be 2, so I kept this setting. I left the input word offset at 0. For the output word number, I need (N)61, offset 0, number of words 2. But every time I try to download the changes to the DNI, the error message appears and the changes are not allowed. Any help would be appreciated. By the way, I'm "viewing" the DeviceNet network in RSNetWorx for DeviceNet, via a 1770-KFD. Thanks, Richard Byrne.

RIO? = Remote I/O? Sorry, not very familiar with all the acronyms Ummmm.... Will I have to configure the drive's frequency select as "4-20mA" then? In order to send the drive a specific frequency I mean... Richard

Thanks for that link, I'll look it over. Do you mean that my PLC-5 ladder logic will have to send the relevant control bits to the drive to change the frequency? Richard.

Excellent, thanks for your quick responses... I intend to use an analog input card with a dc generator tachometer to "sense" speed of motor rotation. The drive will be connected to the PLC via a 1203-GD1 communication module - all of the equipment used is available at college. I will also be attempting to hook up a HMI (don't know which one yet), to provide some sort of visual feedback. The speed of the motor will be altered by a proney (spelling?) brake attached to the shaft - I am aiming to increase the output frequency of the drive as the motor is loaded down, so that a constant speed will be kept. If speed increases too much, the motor will slow down. My initial questions are: * Can the drive be programmed as a stand-alone unit to cycle through several preset frequencies in its own little program? I've looked at the drive's instruction manual and haven't found any help there. * Where can I find information about communicating between the PLC and the drive via the 1203 comms module? The datasheet (user manual) for the module has some information, but I'm thinking that more info. could help. The programming itself is not too much of an issue - I have some exposure to the SLC-500 and MicroLogix 1500 from this past semester which I can use to help me along. There is one other thing though - how would the speed feedback normally be accomplished. I realise that the voltage generated by the tachometer will be proportional to the speed of rotation, so is it just a case of scaling the voltage produced to match the range of motor speeds? Then I'd have to think about some way of altering the output frequency to adjust the speed. Any help, such as application notes, would be fantastic. I'm not expecting everything to fall into my lap, but I would really appreciate as much help as possible. Thanks again, Richard.

Hi, I was wondering whether anyone has had any experience with programming Allen-Bradley's 1305 adjustable ac drive. I've chosen to base my final-year project at college on this drive (that's the one I have access to). I plan to control its speed with a PLC-5. Any guidance or pointers you have would be appreciated - I have numerous questions which have arisen from reading the instructuin manual. Thanks in advance, Richard.

Thanks HalBishop, now my program works like a charm. Does anyone feel that a bad programmer is one that asks too many questions? Richard

I came a cross a problem today which asked me to write a program which would toggle between two compressor motors each time the compressor tank needed to be re-filled. The problem gave a condition that I could only use one internal relay instruction. Could anyone offer a suggestion? Thanks, Richard.

Thanks for the links, I'll have to look at them in greater detail. Yeah I tried looking in the teacher's solution guide for an answer and it said that the solution depended on the PLC used - the book covers PLC-5 and the SLC-500 in its examples. There's also limited coverage of the PLC-2. Thanks again, Richard.

Hi, could anyone help. I am faced with a problem that requires me to write a program for a SLC-500 PLC which will run a car wash. It's a text book problem from Programmable Logic Controllers, Third Edition. Page 352, question 7. I am quite capable of programming up the bullet point no. 5 (*LS4...), but don't know how to work in the IF SELECTED part for the hot wax vale. I thought about subroutines, but didn't think it would work. Help would be appreciated, I'm a college student. Thanks. The question reads: "Using whatever PLC sequencer output instruction you are most familiar with, (in my case the SLC-500), develop a program to implement an automatic car wash process. The process is to be even driven by the vehicle, which activates various limit switches (LS1 through LS6) as it is pulled by a conveyer chain through the car-wash bay. Design the ptogram to operate the car wash in the following manner: *The vehicle is connected to the conveyer chain and pulled inside the car wash bar *LS1 turns the water input valve on *LS2 turns on the soap release valve, which mixes with the water input valve to provide a wash spray *LS3 shuts off the soap and the water input valve remains on, to rinse the vehicle, *LS4 shuts off the water valve and activates the hot wax valve, IF SELECTED *LS5 shuts off the hot wax valve and starts the air-blower motor *LS6 shuts off the air blower. The vehicle exits the car wash" -Richard-