Automatic detection of touch plane type

An interface circuit for a touch plane operator input device, the interface circuit being capable of interfacing to (1) a first type of touch plane operator input device having an X-axis resistive layer and a Y-axis resistive layer, the X-axis layer having first and second X-axis bus bars and the Y-axis layer having first and second Y-axis bus bars, the first type including first, second, third and fourth terminals that are connected to different ones of the first and second X-axis bus bars and the first and second Y-axis bus bars, wherein when a voltage is applied to the first and second X-axis bus bars and the Y-axis layer touches the X-axis layer, a voltage is produced at one or both of the first and second Y-axis bus bars that is indicative of the X-position of the touch, and wherein when a voltage is applied to the first and second Y-axis bus bars and the X-axis layer touches the Y-axis layer, a voltage is produced at one or both of the first and second X-axis bus bars that is indicative of the Y-position of the touch, and (2) a second type of touch plane operator input device having a resistive layer and a wiper layer, the resistive layer comprising first, second, third and fourth input terminals and the wiper layer having a fifth terminal, wherein when voltages are applied to the first, second, third and fourth terminals and the wiper layer touches the resistive layer, a voltage is produced at the fifth terminal that is indicative of the X-position of the touch, and wherein when the polarity of the voltage applied to two of the terminals is reversed, a voltage is produced at the fifth terminal that is indicative of the Y-position of the touch, the interface circuit comprising:

• an analog switch matrix, the analog switch matrix including first, second, third, fourth and fifth terminals which are adapted to be operably connected to the first, second, third and fourth terminals of the first type of touch plane operator input device and to the first, second, third, fourth and fifth terminals of the second type of touch plane operator input device, and the programmable analog switch matrix comprising a plurality of switches that define a plurality of different configurations of the programmable switch matrix;
• an analog-to-digital converter, wherein if the interface circuit is connected to the first type of touch plane operator input device, then the analog-to-digital converter receives analog input data by way of the analog switch matrix from at least two of the first, second, third and fourth terminals of the first type of touch plane operator input device and digitizes the analog input data to produce digital input data, wherein if the interface circuit is connected to the second type of touch plane operator input device, then the analog-to-digital converter receives analog input data by way of the analog switch matrix from at least one of the first, second, third, fourth and fifth terminals of the second type of touch plane operator input device and digitizes the analog input data to produce digital input data;
• and
• wherein, in the plurality of different configurations, the plurality of different switches establish different connections with the touch plane operator input device to sense impedance characteristics of the touch plane operator input device, thereby permitting the interface circuit to be used to distinguish the touch plane operator input device as being either the first type of touch plane operator input device or the second type of touch plane operator input device;
• and
• wherein the interface circuit is further capable interfacing to a third type of touch plane operator input device, the third type of touch plane operator input device having an X-axis resistive layer and a Y-axis resistive layer, the X-axis layer having first and second X-axis bus bars and the Y-axis layer having first and second Y-axis bus bars, the first type including first, second, third and fourth terminals that are connected to different ones of the first and second X-axis bus bars and the first and second Y-axis bus bars, wherein when a voltage is applied to the first and second X-axis bus bars and the Y-axis layer touches the X-axis layer, a voltage is produced at one or both of the first and second Y-axis bus bars that is indicative of the X-position of the touch, and wherein when a voltage is applied to the first and second Y-axis bus bars and the X-axis layer touches the Y-axis layer, a voltage is produced at one or both of the first and second X-axis bus bars that is indicative of the Y-position of the touch, and wherein the third type further includes a plurality of terminals that provide feedback pertaining to at least two of the voltages at the first and second X-axis bus bars and the first and second Y-axis bus bars.

An interface circuit for a touch plane operator input device, the interface circuit being capable of interfacing to (1) a first type of touch plane operator input device having an X-axis resistive layer and a Y-axis resistive layer, the X-axis layer having first and second X-axis bus bars and the Y-axis layer having first and second Y-axis bus bars, the first type including first, second, third and fourth terminals that are connected to different ones of the first and second X-axis bus bars and the first and second Y-axis bus bars, wherein when a voltage is applied to the first and second X-axis bus bars and the Y-axis layer touches the X-axis layer, a voltage is produced at one or both of the first and second Y-axis bus bars that is indicative of the X-position of the touch, and wherein when a voltage is applied to the first and second Y-axis bus bars and the X-axis layer touches the Y-axis layer, a voltage is produced at one or both of the first and second X-axis bus bars that is indicative of the Y-position of the touch, and (2) a second type of touch plane operator input device having a resistive layer and a wiper layer, the resistive layer comprising first, second, third and fourth input terminals and the wiper layer having a fifth terminal, wherein when voltages are applied to the first, second, third and fourth terminals and the wiper layer touches the resistive layer, a voltage is produced at the fifth terminal that is indicative of the X-position of the touch, and wherein when the polarity of the voltage applied to two of the terminals is reversed, a voltage is produced at the fifth terminal that is indicative of the Y-position of the touch, the interface circuit comprising:

• an analog switch matrix, the analog switch matrix including first, second, third, fourth and fifth terminals which are adapted to be operably connected to the first, second, third and fourth terminals of the first type of touch plane operator input device and to the first, second, third, fourth and fifth terminals of the second type of touch plane operator input device, and the programmable analog switch matrix comprising a plurality of switches that define a plurality of different configurations of the programmable switch matrix;
• an analog-to-digital converter, wherein if the interface circuit is connected to the first type of touch plane operator input device, then the analog-to-digital converter receives analog input data by way of the analog switch matrix from at least two of the first, second, third and fourth terminals of the first type of touch plane operator input device and digitizes the analog input data to produce digital input data, wherein if the interface circuit is connected to the second type of touch plane operator input device, then the analog-to-digital converter receives analog input data by way of the analog switch matrix from at least one of the first, second, third, fourth and fifth terminals of the second type of touch plane operator input device and digitizes the analog input data to produce digital input data;
• and
• wherein, in the plurality of different configurations, the plurality of different switches establish different connections with the touch plane operator input device to sense impedance characteristics of the touch plane operator input device, thereby permitting the interface circuit to be used to distinguish the touch plane operator input device as being either the first type of touch plane operator input device or the second type of touch plane operator input device;
• and
• wherein, if the interface circuit is connected to the first type of touch plane operator input device, then the first, second, third and fourth terminals are connected to the first X-axis bus bar, the second X-axis bus bar, the first Y-axis bus bar, and the second Y-axis bus bar, respectively.

An industrial control system comprising:

• (A) a plurality of input and output devices;
• (B) a communication network;
• (C) a control system, the control system being coupled to the communication network and executing a user program to control output status of the plurality of output devices based on input status information from the plurality of input devices;
• (D) an operator interface, the operator interface further including
• (1) a touch screen including
• (a) a display, the display displaying the input and output status of at least a portion of the plurality of input and output devices, and
• (b) a touch screen sensor system, and
• (2) an integrated circuit, the integrated circuit including
• (a) an analog switch matrix, the analog switch matrix being coupled to the touch screen sensor system, the analog switch matrix having a plurality of different configurations, the analog switch matrix receiving an input and selectively supplying the input to the touch screen sensor system based on the configuration of the analog switch matrix to identify a type of touch screen connected to the analog switch matrix,
• (b) a digital signal processor, the digital signal processor determining the touch screen type based on the response of the touch screen to the input in the plurality of different configurations of the analog switch matrix, and
• (c) a communication network interface, the communication network interface coupling the operator interface to the communication network, and
• wherein the integrated circuit senses an impedance across first and second terminals of the touch plane operator input device and processes the sensed impedance to identify the type of touch plane operator input device connected to the interface circuit, and wherein the interface circuit is capable of identifying at least three of the following types of touch plane operator input devices:
• 4-wire touch plane operator input devices, 5-wire touch plane operator input devices, 7-wire touch plane operator input devices, and 8-wire touch plane operator input devices.

An internet access device comprising:

• (A) a touch plane operator input device, the input device including an input device sensor system;
• (B) a display, the display displaying information received from the internet;
• and
• (C) an integrated circuit, the integrated circuit including
• (1) an analog switch matrix, the analog switch matrix being coupled to the input device sensor system, the analog switch matrix having a plurality of different configurations, the analog switch matrix receiving an input and selectively supplying the input to the input device sensor system based on the configuration of the analog switch matrix to identify a type of touch plane operator input device connected to the analog switch matrix,
• (2) a digital signal processor, the digital signal processor determining a touch plane operator input device type based on the response of the input device sensor system to the input in the plurality of different configurations of the analog switch matrix, and
• (3) a communication network interface, the communication network interface coupling the internet access device to the internet, and
• wherein the integrated circuit senses an impedance across first and second terminals of the touch plane operator input device and processes the sensed impedance to identify the type of touch plane operator input device connected to the interface circuit, and wherein the interface circuit is capable of identifying at least three of the following types of touch plane operator input devices:
• 4-wire touch plane operator input devices, 5-wire touch plane operator input devices, 7-wire touch plane operator input devices, and 8-wire touch plane operator input devices.