Internet PLC Forum

Nice work Gary, I like the method you used. Mine was a bit brute force and live with it.

Old guys have to look out for each other.

Thanks and Cheers

Chris

I have been able to resolve this issue by not connecting either end of the shield to ground on the analog cable to the VFD. All works well then for all analaog output voltages.

Prior to removing the ground I made sure everything was grounded and that the DC power supply voltage looked clean. I tried some ferrite beads on the inputs. The noise from the inverter remained on the analog signal with enough strength to overpower the low level analog signal.

My thought is that the ground for the machine has noise on it and when you connect the shield to the ground it is induced in the analog output cabling.  

I know it's not you problem, but it is surely a common one. I would appreciate your thoughts.

I have the #1 DAC output connected to the isolated analog input on a VFD. It works well down to an output of about .7volts At that DAC value and below the DAC output voltage goes back up to around 2 volts when connected to the VFD. I am guessing the DAC output is being overdriven by the power requirements of the VFD?

I have done this in the past with the T100 MD without difficulty.

I have disconnected the DAC output from the VFD and verified that the DAC output does change voltage correctly when the VFD is not connected. The DAC is connected to the VFD input with shielded wire and the shield is grounded on the VFD end only.

So I assume I need som sort of amplifier between the two, any easy way to do this?


Thanks

I am using this F2424 for the first time. The display is working fine but I am not seeing the keypad inputs when pressed using online monitoring. I am using the same key routine from your samples that I have used with the T100MD2424+.

I see no mention to the base address for the F2424 when using the MD-HMI Am I correct that it is the same as the T100MD2424+ ?

The zero key starts at input 25 and input 40 is the last input for the F4 key.

My program works fine in simulation, just not with the hardware.

Possibly I have a hardware problem with the keypad that does not effect the LCD?

Thanks

I need to set up a HSC for input pin 1 and also measure frequency on that same pin.

I believe I saw a note either in the manual or on the forum concerning using the same channel for high speed counting and doing frequency measurment.

As I remeber it said if you set a channel up by doing  HSCCDEF you don't need to also define it as PMON on that channel since is already set up for interrupt operation.

Is this correct?

Good to know. I have thought further on this and have yet another question:

If I have ISR 1 being executed, and the channel #4 interrupt is tripped and waiting for the associated ISR, and then  channel #4  goes low and hight again (another event) will it keep track of several un-serviced intruppts and service them in a FIFO fashion?

In fact this may be a rarity in this system, but it could happen.

I apprecate your input.

Sounds good to me. Thanks for your timley reply.

I have tried several ways to do as you suggested without success.
I would appreciate an example of a ladder that shows how intterputs are defined and used as such.

I have looked through the manuals, the website and the samples and found none.