1.18 Software Gateway for status information¶

The Safety Simplifier comes with two function blocks — the Software Gateway (In) and the Software Gateway (Out) (these blocks were previously named Serial Encoder and Serial Decoder in Simplifier Manager) — for serial communication via the I/O terminals on the Simplifier. Up to 32 signals can be sent and received with each block. The blocks must be configured correctly to encode and decode the information. The configured terminals can then be connected to another Simplifier, or another PLC.

Warning

The serial information is not safety information, as indicated by the grey color of the function block in Simplifier Manager. These signals are only intended to be used for status information and should never be used for any safety function.

1.18.1 Software Gateway Output¶

The Software Gateway Output takes 3–32 input signals and encodes them to two outputs: Data and Clock. These signals can then be connected to two Status Outputs and connected externally to another PLC via the terminals on the Simplifier.

Figure 1.80 — An example of how to connect some signals to the Software Gateway (Out)

Figure 1.80: An example of how to connect some signals to the Software Gateway (Out).

1.18.1.1 Format¶

The data is sent least significant bit first, and most significant bit last (the bit on input 1 is sent first, then input 2, then input 3, etc.). The data output changes value on the clock high flank and is clocked on the clock low flank (as shown in Figure 1.81).

The data is sent in "packets" of bits. The packets are separated by the time given by the Inter-character Duration. During this time both Data and Clock are low. There is always an extra time (equal to the Half Bit Time) after the Inter-character Duration before each packet. This lets the Software Gateway Input block use the same Inter-character Duration setting as the Software Gateway Output.

Figure 1.81 — Software Gateway Output timing diagram

Figure 1.81: Software Gateway Output timing diagram.

The Software Gateway Output has three properties: Time between packets (ms), Half Bit Duration (ms), and Inputs.

Time between packets — the time the clock and data signals will be low between each packet of data. This is so the receiver knows when one packet ends and the next begins. This must be greater than the Half Bit Duration.
Half Bit Duration — how long the clock signal is high for each bit sent out.
Input Count — sets how many signals will be encoded. Up to 32 signals can be encoded.

1.18.2 Software Gateway Input¶

The Software Gateway Input can be configured to decode a signal encoded by a Software Gateway Output from another Simplifier, or from another PLC. The Software Gateway Input has three properties: Inter-character Duration (ms), Timeout (ms), and Output Count. The Inter-character Duration tells the function how much time should indicate a new packet.

Inter-Character Duration — should be set to the same value as the Inter-character Duration of the Software Gateway Output that is encoding the signal.
Timeout — can be set to 1000 ms (1 second), or 10 times the Inter-Character Duration (whichever is highest). If the clock signal is low for this time (for example if the cable is disconnected), all the outputs from the Software Gateway Input will be set to 0.
Output Count — how many signals the encoded data contains. Select the same amount as inputs on the connected Software Gateway Output.

Figure 1.82 — An example of how to connect a Software Gateway Input

Figure 1.82: An example of how to connect a Software Gateway Input. The Data and Clock signals are externally connected to the data and clock outputs from the sending unit.

1.18.3 Serial communication via I/O Terminals¶

To send data via the I/O terminals to other Simplifiers, the properties of both the Software Gateway Output and the Software Gateway Input can be left as they are. The default values for these properties are optimized for communication between Simplifiers via I/O.

Input Count and Output Count can be set to however many signals should be sent.

The output terminal connected to the Data output of the Software Gateway Output should be connected externally to the input terminal connected to the Data input of the Software Gateway Input on the receiving Simplifier. The same should be done for the Clock signal, as seen in Figure 1.85.

Note

Any transistor I/O can be used. For this example, the sender is using terminal 12 for the data output and terminal 14 for the clock output (see Figure 1.84). The receiver is using terminal 10 for the data input and terminal 13 for the clock input (see Figure 1.83).

Figure 1.83 — An example of a receiving node

Figure 1.83: An example of a receiving node. Terminal 3 has been configured as the Data input, and terminal 5 has been configured as the Clock input.

Figure 1.84 — An example of a sending node

Figure 1.84: An example of a sending node. Terminal 9 has been configured as the Data output, and terminal 11 has been configured as the Clock output.

Figure 1.85 — How to externally connect two Simplifiers that communicate serial information via I/O Terminals

Figure 1.85: How to externally connect two Simplifiers that communicate serial information via I/O Terminals.

1.18.4 Configuration for communication with other PLCs¶

1.18.4.1 Receiving signals from other PLCs¶

To receive serial data from other PLCs, the Software Gateway Input can be used. See the documentation for the other PLC for details on how the encoding function works for that PLC.

1.18.4.2 Sending signals to other PLCs¶

To send serial data to other PLCs, the Software Gateway Output can be used. See the documentation for the other PLC for details on how the decoding function works for that PLC. Make sure the receiving PLC is configured correctly to receive the signals.

1.18.4.3 Function blocks for communication with PLCs¶

Function blocks for serial communication with other PLC systems (for example Siemens, Beckhoff and Rockwell) are available for download on our homepage.