Communication processor and Modbus TCP
12.4 Universal serial interface (USS) communication
Setting up the MM4 drive
Before you connect a drive to the S7-1200, you must ensure that the drive has the following
system parameters. Use the keypad on the drive to set the parameters:
1. Reset the drive to factory settings (optional).
If you skip step 1, then ensure that these parameters are set to the indicated
values.
2. Enable the read/write access to all parameters (Expert mode).
3. Check the motor settings for your drive. The settings will vary according to
the motor(s) being used.
To set the parameters P304, P305, P307, P310, and P311, you must first set
parameter P010 to 1 (quick commissioning mode). When you are finished
setting the parameters, set parameter P010 to 0. Parameters P304, P305,
P307, P310, and P311 can only be changed in the quick commissioning
mode.
4. Set the local/remote control mode.
5. Set selection of frequency set-point to USS on COM link.
6. Ramp up time (optional)
This is the time in seconds that it takes the motor to accelerate to maximum
frequency.
7. Ramp down time (optional)
This the time in seconds that it takes the motor to decelerate to a complete
stop.
8. Set the serial link reference frequency:
9. Set the USS normalization:
10. Set the baud rate of the RS485 serial interface:
11. Enter the Slave address.
Each drive (a maximum of 31) can be operated over the bus.
12. Set the serial link timeout.
This is the maximum permissible period between two incoming data
telegrams. This feature is used to turn off the inverter in the event of a
communications failure. Timing starts after a valid data telegram has been
received. If a further data telegram is not received within the specified time
period, the inverter will trip and display fault code F0070. Setting the value to
zero switches off the control.
13. Transfer the data from RAM to EEPROM:
726
P0010=30
P0970=1
USS PZD length = P2012 Index 0=(2, 4, 6,
or 8)
USS PKW length = P2013 Index 0=4
P0003=3
P0304 = Rated motor voltage (V)
P0305 = Rated motor current (A)
P0307 = Rated motor power (W)
P0310 = Rated motor frequency (Hz)
P0311 = Rated motor speed
P0700 Index 0=5
P1000 Index 0=5
P1120=(0 to 650.00)
P1121=(0 to 650.00)
P2000=(1 to 650 Hz)
P2009 Index 0=0
P2010 Index 0= 4 (2400 baud)
5 (4800 baud)
6 (9600 baud)
7 (19200 baud
8 (38400 baud)
9 (57600 baud)
12 (115200 baud)
P2011 Index 0=(0 to 31)
P2014 Index 0=(0 to 65,535 ms)
0=timeout disabled
P0971=1 (Start transfer) Save the changes
to the parameter settings to EEPROM
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG