Internet PLC Forum

Dear All
We are a FMD-88 in a larger electronic device to exchange modbus information by RS232 and RS485.
From time to time  we are losing  TCP-IP and ID communication parameters on a power-down/power-up sequence. Typically an emergency stop sequence.
As it happens rarely, it is difficult to understand the reason behind that.
We can recover the FMD using TLServer over RS232 to retrieve a "new" ID, to re-configure / re-connect again by TCP-IP
What could be the reason of that ?
Does this has to do with eeprom ?
Thank in advance for your ideas and support.
Regards
Thierry

Thank you for your feedback.
We will try that and report.
Regards
Thierry

Hello Gary

Thank you for your answer.

I will think over you suggestion and make measurments.
I would have thought that setting a pwm to a new value would have produced a brutal change in frequency like it is the case on micro-controller.

That raises another question related to my first post : What happen when you apply a STEPSPEED command immediately followed by a STEPMOVE command while still in the middle of the previous STEPMOVE command ? According to some older posts the built-in stepper motor pulse generator will modify its parameters (frequency and number of pulse). How the frequency transition will occur ? Brutal or according to the acceleration law define by STEPSPEED ?

In advance thank you for your replies and you help !

Regards

Thierry






 

So, we have connected 2 Nano with RS485, without anything else.

We configured the master with no protocol, and the slave with RTU protocol.
the on-line monitoring and view variable is file attached.
The problem is concerning the last byte of the outcom frame , you can see it in the docklight view.
 
Master :
1st scan :
SETPROTOCOL 1,10
SETBAUD 1,&H13
REFRESH
RETURN

Every scan :
                DM[1] = &H03                                  ' node address of slave
                DM[2] = &H03                                  ' function 03
                DM[3] = &H00                                  ' upper 8 bit of address
                DM[4] = &H01                                  ' lower 8 bit of address
                DM[5] = &H00                  ' upper 8 bit of count
                DM[6] = &H01                                  ' lower 8 bit of count
                //X = CRC16 (DM[1],6) & &HFFFF  ' compute the CRC16 of DM[1] to DM[6]
                DM[7] = 212       //X / 256              ' upper 8 bit of CRC16
                DM[8] = 40                         // & &HFF                           ' lower 8 bit of CRC16

                FOR I = 1 to 8          ' send out the MODBUS RTU command in binary
                               OUTCOMM 1, DM[0+I]
                NEXT

                DELAY(100)                                        ' delay for a while to wait for response (30)

                FOR I = 1 to 8                     ' get rest of response
                               DM[10+I] = INCOMM (1)
                NEXT

IF DM[1]=DM[11] and DM[2]=DM[12] and DM[13]=2 and DM[16]=193 and DM[17]=132
else
DM[20]=DM[20]+1
ENDIF

DM[21]=DM[21]+1

                B=DM[14]*256 + DM[15]
                DM[40]=B*66/1000
                REFRESH

IF DM[14]<0 OR DM[15]<0  THEN
DM[22]=DM[22]+1
ELSE
DM[22]=0
ENDIF

IF DM[22]=1 THEN
                DM[31]=DM[40]
                DM[23]=DM[23]+1
ENDIF

IF DM[22]=2 THEN
                DM[32]=DM[40]
                DM[24]=DM[24]+1
ENDIF

IF DM[22]=3 tHEN
                DM[33]=DM[40]              
                DM[25]=DM[25]+1
ENDIF

IF DM[22]=4 tHEN
                DM[34]=DM[40]
                DM[26]=DM[26]+1
ENDIF

IF DM[22]=5 THEN
                SETIO OUT3
                DM[35]=DM[40]
PAUSE
ENDIF

Slave :
SETPROTOCOL 1,1
SETBAUD 1,&H13
REFRESH
RETURN

Dear Gary
Thank you for your long answer.

We did properly set the protocole to mode 10 in order to be sure that we do not interfer with existing MODBUS procedure. We increase the delay to 100 but still we have problems.

We use Docklight software as a viewer of the Rx/Tx frames. And it is clear that sometimes the latest bytes of the frame is not H28 has it should be. It can be any number ....

We alos work with micro-controller ( ST7 and ST8 ). Therefore we know how these components work.

But using the OUTCOM function, we have no way to undertand why the value is not the one we expect. Is it a problem of timing ?

Regards

Thierry

Our problem might comes from the OUTCOM commands . Therefore I prefer to start a new post. Regards Thierry

Dear All

We need to monitor a sensor generating a low frequency signal ( 5 to 50 Hz).
Is it within the range of PULSEFREQUENCY function or is it too low ?

Regards

Thierry