Bryll

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Posts posted by Bryll

  1. Posted

    I used a FX3U with the FX3U-485-BD card to communicate with the VFD inverter without problem. But I had to write to register 40013 to reach 40014 for the speed setting, due to that Modbus register addressing starts with 1 and PLC registers starts with 0. To reach the CW at 40009 did I specify 40008. Have you tried to offset your addressing with 1 ? Sorry, just checked the type of inverter I used, it was the FRD 700 for that project. But it will not surprise me if the registers are the same. I remember that I had to specify in the inverter that it should be controlled (CW) via modbus, and also that the target frequency was via modbus.

  2. Posted · Edited by Bryll

    The digital inputs for PLC's are very often 24VDC, at least it's the most common type I use. Analog inputs are quite often 0-10V, 0-5V, -10- +10V and 4-20mA or 0-20mA. Might have missed one or two analog input types. If you want to use the sensor you specified, you have to build a circuit for its supply voltage. You also need to have a circuit for the I2C communication bus (for the correct voltage levels), and of course implement the I2C communication protocol in the PLC. The I2C bus is developed by Philips Semiconductors, here's the specification. Don't think you can manage that with ordinary digital I/O's, since you need to both read and write data with the same "pin". I would look for a humidity transducer that will give an analog output and could be supplied with 24VDC if I where you. Do a Google search and you'll find several I think. Edit: Forgot to mention that the I2C bus is for communication between components on circuit boards, not with automation equipments.

  3. Posted

    By your description of the sensor do I suspect you can't use ordinary PLC I/O to read data from it. Found a data sheet of the SHT11 The SHT11 is intended for a supply voltage of 3,3Volt. It can only be read by using the I2C communication protocol. I'm afraid you don't need a PLC for this, you need a microcontroller. Data Sheet

  4. Posted

    Yes it works most of the times, but sometimes are two or more lost. The communication light are nice and green until they are disconnected. I tested to lower the baud rate, and couldn't see any difference. Didn't change back to 1,5mbps, don't need it that fast. The drives don't reconnect, I have to do it at each drive. Termination is on at each end, no other is on. Checked the line a couple of times now.

  5. Posted

    All the cables is good, motorcables are of the good expensive shielded type and profibus cable and connectors are also good. One thing that puzzles me is that I had to perform a byte swap on the CW before the inverters would accept it. The speed setting data don't need to be swapped. The feedback SW don't need to be swapped, it's good as it is. The fault bit is always active, even when the inverters don't show any faults or error. Communication speed is set to 93kbps, so I don't think it's a speed issue that they drops out. I have 12 inverters and three Krom Schröder burner control units on the PB communication. If I disconnect the burners will they reconnect as soon as I put back the PB plug. The inverters not. Is there any setting I can do in the parameters of the inverters so they will try to reconnect ?

  6. Posted · Edited by Bryll

    Hello, Tried to get some good and clear answers at the Siemens forum, decided to try here aswell. I have a setup with 12 G120C inverters and three gas burner units on a profibus line. If I unplug any of the devices will I of course get an error from the loaded OB. But, now and then can I lose the connection to two or more of the inverters without any notification. It seems that the communication is up and running, but the don't respond to any commands. The normally green LED on the inverters switch over to flashing red when they stop to respond. They will also show fault code 1910. I am using standard telegram 20, this is also set in the inverters parameter lists. Another funny thing is that the fault bit in the status word is always set. Even when the inverters don't hav any faults or alarms. ZSW looks like this (with or without response from the inverter): Bit 0 = 1 (Ready for switching on) Bit 1 = 1 (Ready for operation) Bit 2 = 0 (Running) Bit 3 = 1 (Fault) On all the time, even when there is no faults in the inverter Bit 4 = 0 (No coast down active) Bit 5 = 1 (No fast stop active) Bit 6 = 1 (Switching on inhibited active) Bit 7 = 0 (Alarm present) Bit 8 = 1 (Speed setpoint - actual value deviation within tolerance) Bit 9 = 0 (Control requested) Bit A = 0 (f or n comparison value reached) Bit B = 0 (I, M or P limit not reached) Bit C = 1 (Reserved) Bit D = 1 (No motor overtemperature alarm) Bit E = 0 (Direction of motor rotation) Bit F = 0 (Display CDS) Anything I might have missed or done wrong ?

  8. Posted

    Hi I have an upcoming project where we should upgrade an old S5 cpu to a newer S7 300 cpu, probably will it be a 317F. Most likely can we get the old S5 software. Is it possible to easely convert it from Step 5 to Step 7 or TIA V12 ? Or do I need to get my hands on an old Step 5 version and manually copy over the code ?

  9. Posted

    Don't know how I could have missed that, been looking in that manual several times. Thanks for pointing me in the right direction The strange thing is that the Modbus slave communication I have on channel 2 is up and running.

  10. Posted

    Recompiled and downloaded the code and the error code appears at once. So it's nothing that pops up after a while. Anyone out there that has a clue ?

  11. Posted

    What does this error code 3821 mean (attached picture) ? Gx IEC Dev. 7.04 FX3U-16MT/DSS with FX3U-ENET P502, FX3U-485BD and FX3U-485ADP. Communication is up and running correctly on the two RS-485 lines, and the Modbus TCP line. Can't find any information about the error code. link_error.bmp

  13. Posted

    You will find the variable settings for the compiler here (picture). Make sure you don't go into the area you have in the global variable list. The communication blocks use a lot of integers, so start to increase the area for the D-devices. I don't normally work with GX Dev. so I might be corrected. device_label_settings.bmp

  15. Posted

    When connected to a voltage source, you should use V+ and VI- terminals on the FX2N-4AD module. But when you switch over to current mode should you place a jumper between V+ and I+ terminals. Have you done that ?

  17. Posted

    Hi all, I have 12 units (G120C) that I want to control via profibus. They are addressed from 2 to 13, with the CPU 315 at address 1 as master. I use the "standard telegram 20" for the communication. (Read 6 words, Write 2 words) Since I'd like to keep the IW and QW start addresses similar and at a low range, did I start with QW100 and IW100 for the first unit. The I/O addresses for the second unit starts at QW112 and IW112, but when I try to set the I/O addresses for the third unit will the software correct my typed IW124 to IW128. Four bytes higher. Same with the next two units, but not with the rest of them. All other I/O addresses for digital and analog I/O's are below IW100 and QW100 Can anyone please explain to me why this happens?

  18. Posted

    Thanks Homer, I'll give it a try. But, are the date/time variables hidden in the PLC ? I'm used that I can access them directly just as easy that I read MW50 or any other integer.

  19. Posted

    I have V11 and V12 installed on the computer, and actually V13 in a box on my desk. The reason why V13 is in the box is that I can't install it since I'm running XP on this computer. To get started on a new computer will take a lot of time that I don't have at the moment. So, I guess I have to continue searching for a workaround if there's one for this problem.

  20. Posted

    I noticed a "bug" in WinCC V12. It seems impossible to ungroup objects the normal way, anyone that knows a workaround this problem ? Can it really be that bad so I need to create new objects and avoid grouping them ?

  21. Posted

    Hi, I would like to set up a S7-315 2PN/DP with two TP900 panels and read the system clock from the PLC. The clock should also be possible to set from the panels. I have been reading the messy information given by Siemens help pages in the software (TIA V12). It's not very clear how to control the system clock from the panels, at least not for me since I'm a Mitsubishi guy. Another guy at the forum once wrote "When it comes to Siemens, information is as clear as mud" Do I need to write PLC code using some SFB's to be able to set date and time ? In wich registers can the clock data be found ? Is it possible in runtime to switch between 12 and 24 hour format ? And so on......

  24. Posted

    Hi all, Need some help how to read and write data from a 315 2PN/DP to a couple of G120C drives. I have been searching Siemens website for two days now without finding any relevant information. The software used is Step7 V12 Professional Update 3. What I need to know is how the address map in the G120C looks. I know the start addresses for the input and output area of each inverter, but have no clue what is in these registers. You have to consider that I am a Mitsubishi guy, so please be patient