(a) What settings are required when a Siemens 200 PLC communicates with KingSCADA using the MPI protocol?
1) The machine running KingSCADA needs to have Siemens' STEP7 Microwin 3.2 programming software installed. Our driver needs to call the MPI interface library functions provided by the programming software;
2) The MPI communication card CP5611 needs to be installed in the computer's slot. Use the dedicated cable and network connector provided by Siemens to connect the CP5611 card to the S7-200's port (connect pins 3 and 8 of the CP5611 card to S7-200's port 3 and 8 respectively). Generally, the terminating resistor of the last configured network connector in the MPI network should be set to the ON (active) state.
3) Creating the MPI network in the PLC and correctly setting the communication baud rate;
4) Configure the PG/PC interface parameters in the control panel; refer to the KingSCADA electronic help for details.
(II) How to implement the hardware wiring for communication between KingSCADA and Siemens 200 PLC via modem using the freeport protocol?
Connect a standard PPI cable to the device. Connect the modem's 9-pin connector to the PPI cable using a standard 232 crossover cable. On the modem side of the 232 crossover cable, pins 1, 4, and 6 need to be shorted, and pins 7 and 8 need to be shorted.
(III) Can one S7 200 PLC communicate with two host computers via serial port?
If the serial cable method is not feasible, the following two methods can be considered:
1) The PLC is configured using the MPI protocol, so each of the two host computers needs to be configured with an MPI card;
2) Of the two PCs, one acts as the data acquisition station and communicates with the PLC, while the other acts as the client and communicates with the data acquisition station.
(iv) Why did the Siemens 200Plc fail to communicate with KingSCADA via the PPI protocol?
Please check if the following settings are correct: 1) User programming cable DIP switch settings: In the programming cable DIP switches, the 5th terminal is for setting the communication protocol: DIP switch set to 0 indicates PPI/Freeport; DIP switch set to 1 indicates PPI (master); When the user uses the PPI protocol to communicate with KingSCADA, the DIP switch should be selected according to the corresponding PPI/Freeport DIP switch value;
2) PPI communication transmits 11 bits of data, so it is recommended that customers select 8 data bits, 1 stop bit, and even parity DIP switch (the default DIP switch is 11 bits). Furthermore, the PLC's baud rate must be consistent with the PPI and KingSCADA settings.
3) The programming software must be KingSCADA that starts running offline.
(v) When a Siemens 200 PLC communicates with KingSCADA via the Modbus protocol, how do the register addresses defined in KingSCADA correspond to the PLC addresses?
The mapping relationships are as follows: 0-Q, 1-I, 3, 4, 8, 9-V;
The correspondence between the dd numbers 3, 4, 8, and 9 and the offset address (actual address - 1000) of the V register in the PLC: In KingSCADA, (dd number of register - 1) * 2 = offset address of the V register in the PLC. In KingSCADA, 40031 corresponds to PLC VW1060 (register 4 in KingSCADA represents a SHORT type variable). In KingSCADA, 90640 corresponds to PLC VD2278 (register 9 in KingSCADA represents a FLOAT type variable).
(vi) What precautions should be taken when a Siemens 200 PLC communicates with KingSCADA via the Modbus protocol?
The following points should be noted: 1) The corresponding initialization program (KVmoddbus.mwp) needs to be downloaded to the PLC, provided by Asia Control. This program's default PLC communication port is port0, address is 2, baud rate is 9600, and there is no parity check (the address and baud rate can be modified using VB8 and SMB30 in program SBR0);
2) Because the PLC Modbus protocol program occupies addresses V1000 and earlier, the registers used by the user in writing the logic control program must not conflict with the V area addresses occupied by the protocol provided by Asia Control.
3) When communicating with KingSCADA via the Modbus protocol, the switch on the CPU must be set to the RUN state. Otherwise, the Modbus communication program in the PLC will not be running, and KingSCADA and the device will definitely fail to communicate via the freeport protocol.
(vii) Does the S7 300 MPI cable connection support communication with KingSCADA via GPRS?
Not supported. KingSCADA's GPRS communication method requires the creation of a virtual serial port and data communication through this port. However, for the MPI protocol, our MPI driver communicates with the PLC by calling Siemens PLC's dedicated dynamic link library (s7onlinx.dll, etc.), not directly through the serial port.
Other drivers with similar calling methods also do not support GPRS connections.
(viii) When KingSCADA communicates with multiple Siemens S7-300 and 400 PLCs via the DP protocol, how should the device addresses be defined?
1) Hardware connection: Inserting a CP5611 (or CP5613) into the computer allows multiple S7-300/400 PLCs to be connected to a single DP bus.
2) DP Protocol Configuration: All PLCs must have a DP Slave station configured. CP5611 (or CP5613) requires a unique DP master station configured via Simatic net.
3) Device address definition in KingSCADA: Select PLC/Siemens/S7-200 Series (DP)/Profibus-DP, the device address is fixed at 1.1 (this address is unrelated to the address setting of the slave PLC).
(ix) When a Siemens 300 PLC communicates with KingSCADA via an MPI communication card, can dual-device redundancy be achieved?
Yes, it's possible. 1) One CP5611 card can connect to two S7300 PLCs (using the programmable connector provided by Siemens);
2) Create two S7300 PLCs in the KingSCADA software, with device addresses 7.2 and 8.2 respectively (the device address should be set according to the actual device). The sign before the decimal point refers to the PLC address, and the sign after the decimal point is the slot number where the CPU is located. These two PLCs are defined separately in the STEP7 programming software, so the slot numbers are the same except for the PLC addresses.
3) In KingSCADA, you only need to define the variables of the master device.
(x) Which communication links are supported between KingSCADA and Siemens 300/400 PLCs? Is Siemens software support required?
1) MPI cable communication method: The computer hosting KingSCADA must have STEP7 programming software installed;
2) MPI communication card method: The computer hosting KingSCADA must have STEP7 programming software installed;
3) Ethernet communication: No STEP7 or Simatic net communication software needs to be installed on the computer where KingSCADA is located;
4) Profibus-DP method: Requires the installation of STEP7 programming software and Simatic net 6.0 (or later) communication configuration software and license on the local machine;
5) Profibus-S7 access method: STEP7 programming software needs to be installed on the computer where KingSCADA is located, but SIMATIC NET software does not need to be installed.
