MM440 SETPOINT on profibus (s7)

Hi,


I have 2 inputs in the PLC for decrease and increase the motorspeed.

The drive MM440 is connected on profibus to a s7-315-2DP master.

In the control word I have bit 13 and 14 to use the MOP (motorized Potentiometer).

SHould I use these bits or should I make MOP in the PLC and use the setpoint in the PZD

Wich one is the fastest and the best ?

Combo said:

Hi,


I have 2 inputs in the PLC for decrease and increase the motorspeed.

The drive MM440 is connected on profibus to a s7-315-2DP master.

In the control word I have bit 13 and 14 to use the MOP (motorized Potentiometer).

SHould I use these bits or should I make MOP in the PLC and use the setpoint in the PZD

Wich one is the fastest and the best ?

Click to expand...

hi....
i think its better u go for the control word bits than going for plc.
its faster and u dont need any logic to be developed for that.. and also u save 2 "VALUABLE" outputs in the PLC since, there is no other factors to be considered...

sueksh

but if you do it in the plc, it is more flexible (easy change of limits and steps,...).
i think it depends on your machine, if it is complicated then i would go for plc ladder programming...

Problem with the MOP speed setting



So I have 2 buttons connected on a PLC, the inputs are interconnected to the MOP Up and the MOP DOWN via profibus...

Problem is that there is a ramp before the setpoint of minimum 2s.

When they want to set a speed setting (the drive gives it's actual speed to a display), it's very difficult to say, let's regulate to 20 m/min.

So, now I have the troubles because of using MOP...

I will trey now via PZD.

I would suggest using PP04

This will give you (from PLC-->Drive):
Word 0, Control Bits
Word 1, Speed Ref +/- 200%
Word 2~Word5 User Defined

From Drive~PLC:
Word 0, Status Bits
Word 1, Actual Speed+/- 200%
Word 2~Word5 User Defined

Don't mop via I/O...if you must right directly to value...not via Up/Down. If your using MOP local on drive just switch between Data Sets.

Nick