Remote A_M Button

Owned by Gary Cane
May 09, 2022


Operator Menu Location: Generic Hardware Operators Auto/Manual


Operator Bitmap:


Functional Description:
The Remote A/M Button operator is a special type of FairNET networking operator that complements the Auto/Manual Button operator. Together, they allow synchronized auto/manual operation of multiple control stations attached to a FairNET network. For example, consider the case where one station contains a network-enabled Auto/Manual Button operator and two other stations on the same controller network each contain a corresponding Remote A/M Button operator. If you switch any one of the three stations from automatic mode to manual mode, the other two stations will also switch to manual operation. If you then adjust the manual output from any one of the three stations, the other two will match that manual output. If you switch any one of the stations back into automatic mode, the other two stations will also switch into automatic mode. When the stations operate in automatic mode, the output signal of the Remote A/M Button operator follows the output of the Auto/Manual Button operator.


In order to associate a Remote A/M Button operator in one schema to an Auto/Manual Button operator in another, both operators must be linked to modules attached to a FairNET channel and their signal name property must match exactly. To synchronize multiple control stations, the schema of one station must have an Auto/Manual Button operator and the schemas of each additional station must each have a Remote A/M Button operator (and the signal name property of all operators must have the same case-sensitive character string).
The Remote A/M Button operator has one analog output and two digital outputs. Digital output indicates the operating mode: it is HIGH when the operator is in manual mode; it is LOW when the operator is in automatic mode. Digital output serves as a network status signal indicating if the Remote A/M Button operator is actively receiving broadcasts from its associated Auto/Manual Button operator. The output is LOW while transmissions are regularly received; the output is HIGH if the operator has not received a broadcast in a user-specified time interval (the broadcast dead-time property of this operator).


Analog output y depends on the operating mode (automatic or manual) and on the network status. When in manual mode, output y is set by push buttons on the device front panel (or, while the network is active, the push buttons of associated devices). When in automatic mode, output y tracks the output of the associated Auto/Manual Button operator while the network is active. If the operator has ceased receiving network transmissions and it is in automatic mode, output y tracks input x, (i.e., y(t)=x(t)).


Remote A/M Button and Auto/Manual Button operators are synchronized over a FairNET network. When the output(s) of one operator changes, the output(s) of the associated operators will follow. But what happens when conflicting commands are simultaneously issued from different control stations? Say a user in one station increases the manual output while a user in another simultaneously reduces the manual output. The station executing the schema with the Auto/Manual Button operator arbitrates conflicting commands. The Auto/Manual Button operator continuously broadcasts the output state that all associated Remote A/M Button operators should assume. When a Remote A/M Button operator deviates from this broadcasted state (e.g., one of its front-panel keys is pressed), it sends a message to the Auto/Manual Button. If the Auto/Manual Button accepts this command it modifies its output state and broadcasts it over the network. The broadcast of the new output state serves to confirm that the Auto/Manual Button has accepted the Remote A/M Button command and to alert all other associated Remote A/M Button operators that they should update their output states. If the Remote A/M Button does not receive confirmation that its message has been accepted after seconds, it reverts to tracking the output state of the Auto/Manual Button operator. Parameter is a property of the Remote A/M Button operator labeled Deviation Time from Remote Signal.


When the operator transitions from automatic mode to manual mode, output y remains at the transition value until modified from the front panel (of any associated control station).


When the operator switches from manual mode to automatic mode, the transition may be abrupt or smooth (bumpless). If the Bumpless Transfer property is not selected, the output will switch instantly from the manual output to the automatic output. When bumpless transfer property is checked, the transition from manual to automatic is guaranteed to be smooth. The nature of the transition (i.e., the transfer profile) can be either exponential or linear.
Let be the difference between the manual output and the automatic output at the instant the operator switches from manual to automatic, . Under an exponential transfer profile, the operator output will be (approximately)

where r is a time constant expressed in minutes. Under a linear transfer profile, the operator output will be (approximately)

where r is a linear decay rate expressed in (input) units/minute.
Note: The following description of the use of input and input applies only while the network connection is not active. While the network connection is active, these two inputs do not affect the output of the Remote A/M Button operator.


Generally, a person will use the faceplate pushbuttons to switch a control station from operating in automatic mode to operating in manual mode (and vice versa). You would also typically rely on a person to make manual output adjustments. However, under certain conditions you may wish to automatically switch the Remote A/M Button operator from one mode to another-and automatically adjust the "manual" output-without user involvement. The Remote A/M Button operator has two secondary inputs that allow you to do just that. You can use digital input to automatically set the auto/manual mode_. And you can_ use analog input to automatically set the "manual" output. These two inputs are edge-triggered, meaning that they override the faceplate pushbuttons and affect the operator output only when their value changes. While these inputs remain fixed, they do not affect the outputs. (Of course, when these inputs affect the output of the Remote A/M Button operator, they also affect the output of associated Remote A_/M Button operators_ as well as the primary Auto/Manual Button operator.)
When the operator is in manual mode and input switches from HIGH (manual) to LOW (auto), the operator will switch into automatic mode and its output y(_t) will (over time) match its input x(t). (If the _Bumpless Transfer feature is enabled, the output will vary according to the equations above.) If the operator is in automatic mode and input switches from HIGH (manual) to LOW (auto), then it will remain in automatic mode.
When the operator is in automatic mode and input switches from LOW (auto) to HIGH (manual) at time , the operator will switch into manual mode and its output y(t) will move toward the value of input at the time of the switch. The transfer of the output-from- -to -occurs in increments and is rate limited by the Key Repeat Time --property,- -. The output will vary as if a user presses the A/M faceplate button to switch to manual and then pressesand holds down-one of the arrow keys until the output reaches the desired value, . Mathematically, we can express this as:

Whenever the manual-override input changes value, the output will move toward that value according to the equation above. (Of course, this occurs only while the operator is in manual mode; otherwise, the input is ignored). In order for the manual input to affect the output, its value must change. Moreover, the magnitude of the change must exceed the Manual Input Activation Threshold property over a period of time called the Manual Input Activation Time, T. In other words,

must be satisfied in for the manual output to begin moving toward .
Do the pushbuttons on the hardware faceplate have precedence over the inputs and ? The answer is that the operator will follow its most recent command. If it is commanded by its inputs to automatically adjust its manual output value, it will do so. If in the process of automatically adjusting the manual output value a person presses one of the arrow keys, the Remote A/M Button operator will follow the key commands. It will not resume its automatic adjustments unless input changes value -- remember that this input is edge-triggered!


User-Defined Properties:
Signal Name. A string label that identifies the operator. This character string is used to associate (synchronize) a Remote A/M Button operator in one schema with an Auto/Manual Button operator in another schema.


Initial State. The operator mode (auto or manual) on startup (at time t=0).

Initial Value. The analog output value on startup (at time t=0). Applicable only if the initial state is set to manual.


Minimum. The minimum analog output value. Applies to both auto and manual modes.


Maximum. The maximum analog output value. Applies to both auto and manual modes.


Increment Magnitude. The magnitude of manual output increments when in manual mode. The manual output will be incremented or decremented by this parameter when (info) a person presses the faceplate pushbuttons, or (ii) input changes value (see the Manual Input Activation Threshold and Manual Input Activation Hysteresis properties below).


Bumpless Transfer. When the operator switches from manual mode to automatic mode, the output signal may differ from input x. If this property is not checked, there may be a discontinuity in the output. When Bumpless Transfer is checked, the transition from manual to automatic is guaranteed to be smooth.


Transfer Profile. When the Bumpless Transfer property is set, the output will transition smoothly from manual mode to automatic mode. This property characterizes the nature of the transition: Exponential or Linear. When the exponential profile is selected, the difference between the manual output and automatic output will decay exponentially. When the linear profile is selected, the difference will decay linearly.


Transfer Rate. The rate at which the difference between manual output and automatic output will decay when the Bumpless Transfer property is set. When the exponential profile is selected, this parameter defines the exponential decay rate expressed in minutes. When the linear profile is selected, this parameter defines the linear decay rate in input units/minute.


Use Alpha-Numeric Displays. When this property is selected, the output value will be presented on the alpha-numeric displays while the operator is in manual mode.


Number of Significant Digits to Display. The number of significant digits to use when displaying the manual output on the alpha-numeric displays.


Lock in Manual State. When this property is selected, the operator will only function in manual mode. A person (or an associated Auto/Manual Button or Remote A/M Button operator) will not be able to switch it into automatic operation.


Maximum Broadcast Dead-Time. The period of time (in milliseconds) that may elapse before the operator indicates that it has not received a broadcast signal from its associated Auto/Manual Button operator (switches output b to HIGH). Output b remains low while the operator actively receives the broadcasted signal.
Display A/M State Input. The state input is used to automatically switch the operator state--automatic or manual--without front-panel user interaction. This input is not used in most applications and can remain disconnected (but Design Pad will issue a warning upon processing). When this property is not checked, Design Pad will not display the input pin and will not issue a warning upon processing.
Display Manual Input. The manual input is used to automatically adjust the "manual" output without front-panel user interaction. This input is not used in most applications and can remain disconnected (but Design Pad will issue a warning upon processing). When this property is not checked, Design Pad will not display the input pin and will not issue a warning upon processing.
Manual Input Activation Threshold. When the Auto/Manual Button operator is in manual mode, the output can be adjusted automatically using input . In order for automatic adjustments to begin, the manual input must change value. The magnitude of the change must exceed this parameter. (And it must exceed this value for a period of time defined by the Manual Input Activation Time property below.)
Manual Input Activation Time. When the Auto/Manual Button operator is in manual mode, the output can be adjusted automatically using input . In order for automatic adjustments to begin, the manual input must change value. The magnitude of the change must exceed a threshold value over a period of time (in milliseconds) defined by this parameter.


Deviation Time from Remote Signal. While the network is active, the Remote A/M Button operator is "tuned" to the broadcasted output state of an associated Auto/Manual Button operator. However, it may deviate from the Auto/Manual Button when its faceplate pushbuttons are pressed. When this happens, the operator sends a message over the network to the Auto/Manual Button and waits for confirmation that the Auto/Manual Button has accepted its command. While it waits for confirmation, its output state may deviate from the Auto/Manual Button operator broadcasts. This parameter indicates how long (in milliseconds) the operator can deviate from the Auto/Manual Button broadcasts. (If it has not received confirmation after this time elapses, the operator will resume tracking the broadcasted output state from the associated Auto/Manual Button operator.)

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See Also: Auto/Manual Button