Click PLC Serial Communication Timing

[@DavidPrettybreadt]

Thanks a lot for your great videos. I enjoy working with the Click PLCs they are fantastic compact and reliable. Learned a bunch of new stuff. I noticed that your high and low limits do not change. This is because you haven't pressed the write button next to them to actual change DS51 and 52 in the Data View.

[@ACCautomation]

Hi David, Great observation. Thanks for pointing that out. I did realize this after editing the video but thought that it is a minor error on my part. Thanks for the comments, David. Garry

[@abrahamtrauco6899]

Hi. If I just want to receive information, I have to use only the receive block?. I mean, it's not necessary to put a "send block" ?. I am saying that because I've been trying to read parameters from a "Power logic meter PM5560 SCHNEIDER" but I had no success.

[@ACCautomation]

Hi Abraham, You are correct that you will only require a receive block to read from a Modbus address. accautomation.ca/click-plc-serial-communication-timing/ Is there an error code coming back after you try to communicate? Here are the Modbus addresses for the meter: www.se.com/ww/en/faqs/FA234017/ Regards, Garry

[@abrahamtrauco6899]

@@ACCautomation Hi. Thank you for your answer. Today I tried to read "INT16" parameters and I had success. The problem is that many of the parameters are "FLOAT32" and if in the "Receive block" I put "DS1", I got error. So I tried to use "DF1" that is a "float" variable, I got no error, but I got numbers lile 1.57278 E12 or -1.5893 E-11. I want to read current, voltage, etc, and those are "float" variables, so I don't know what to change.

[@ACCautomation]

@@abrahamtrauco6899 Congratulations on being able to communicate. Since the INT16 numbers work, the correct addresses are being used. Sometimes these are offset by 1. In order to have the information read correctly, I would try to use the Word Swap on the Recieve instruction. Regards, Garry

[@abrahamtrauco6899]

@@ACCautomation Thank you so much, It worked. But I still need some help. I just want to read parameters(maybe 10 or more), so it means I have to use many "receive" blocks. The problem is that I don't know a lot about "Programming in PLC" so I tried to use the logic you used with the timers, but I had no success. Maybe you can give me some comments about it or tutorials I should watch. Thanks a lot.

[@ACCautomation]

@@abrahamtrauco6899 The following post is associated with this video. accautomation.ca/click-plc-serial-communication-timing/ The success and error flags that can be assigned to the receive instruction should be used to trigger the next receive instruction. Timers are used to indicate the end of the transmission and to determine errors with communication. Here is an older post showing just using timers: accautomation.ca/click-plc-send-and-receive-instructions/ This does not always work. A revised program is listed near the end of the post using a shift register to time the Modbus communication. I hope this helps you out. Regards, Garry

[@CraigHollabaugh]

I've watched about 35 of these videos to get up to PLC speed. Looking through your examples, all the serial comm are for modbus, I have a measurement device that talks straight ascii (very simple poll/response). Do you have a video serial ascii tutorial similar to this? I also need to convert ascii number to a click float, which I think uses pack/copy. Any advise on how to proceed?

[@ACCautomation]

Hi Craig, The following post will use ASCII input and output to represent Modbus ASCII Protocol. All calculations are done in the PLC. accautomation.ca/click-plc-modbus-ascii-protocol/ You are correct about using the pack/copy command when casting between Text and DF. Here is some information on doing this. www.automationdirect.com/microsites/clickplcs/click-help/Content/239.htm Regards, Garry

[@CraigHollabaugh]

@@ACCautomation The accauto link you sent fully explains what's needed to address my issue. Its more complicated than expected, this is due to ladder programming environment. However all the rungs make sense and are quite clever. Thanks for your help.

[@CraigHollabaugh]

Hey, I got my serial ASCII code running to query a multiple channel temperature monitor. Code sends and receives ASCII, copy/packs the result into a float then sets thresholded relay outputs. Even have address pointers operating to cycle through each channel in the temp monitor. I learned a ton about ladder logic, click IDE, debugging, sequencing, timeouts, error codes, one shots, etc. Thanks again for your help, this video and the ACC documentation.

[@ACCautomation]

@@CraigHollabaugh Thank you very much for the feedback. I'm glad that you got it going and we could help. Garry

[@mondim6600]

What about communicating to multiple modbus RTU slave devices?

[@ACCautomation]

Hi Mondi M, You would continue to cascade the Recieve and Send instruction in the program. The bits from the instructions are used to trigger the next instruction. Here is a further explaination. accautomation.ca/click-plc-serial-communication-timing/ Regards, Garry

[@mondim6600]

@@ACCautomation Thanks for the quick response Gary. I attempted to do so and after adding the receive instruction for the second node the Error bit turns on. I can communicate to the devices one at a time using the cascading method shown in the video but cannot have multiple devices without error. I can communicate to both devices using a counter and a delay of 100ms for each Send/Receive instruction. I would really like to be able to use the cascading bits and not counting and delays. Any idea what could be the issue?

[@ACCautomation]

@@mondim6600 Along with the error bit, there should also be an error code returned by the instruction. Can you tell me what that is? Please check to ensure that each of the Modbus Slave nodes has a unique address. If two are the same this would cause errors as well. If you want, please send me your ladder code to [e-mail] I can do a quick check of the code. Regards, Garry

[@happylivechannel5720]

I need your help bro....how to wiring close proximity sensor PNP (NO) to Siemens Logo 24RCE...and how to connect Start and Stop pushbutton....for sensor i using i4,i5,i6 input in siemens logo...please help me bro

[@ACCautomation]

Hi HappyLive Chanel, Page 24 of the following logo manual will show the wiring diagram of the logo. cache.industry.siemens.com/dl/files/461/16527461/att_82564/v1/Logo_e.pdf I can only speak in general terms since I do not know your exact sensor. The common for the Logo input is 0VDC. The switching wire of the sensor (Black) goes to the input point of the logo. The +VDC (Brown) of the sensor will go to the +VDC supply. Regards, Garry

[@happylivechannel5720]

@@ACCautomation So how the output connection on logo?....and how to wire start and stop pushbutton on logo?

[@ACCautomation]

@@happylivechannel5720 Start and stop pushbuttons can be wired as per the same page 24 of the manual. The common input point of the logo is 0VDC. The input point of the logo is wired to one side of the pushbutton and the other side of the pushbutton is wired to +VDC to complete the circuit. Page 31 of the logo manual shows the wiring of the output. Relays provide a dry contact. Ensure that the voltage and current of the output load are less than the rating of the logo relay output. I hope this helps you out. Regards, Garry

[@happylivechannel5720]

@@ACCautomation okey...thanks bro

[@happylivechannel5720]

@@ACCautomation One more question bro....if i using i4 input for sensor in siemen logo, so how about to wire output of sensor at siemen logo?