R_MX: Read multiple multistate

R_MX reads and evaluates the present values of multiple (up to 16) multistate data points with present value of datatype Unsigned, according to a selectable evaluation function, and calculates a resulting value that can be used to update a Result BACnet object.

Compatible data points:

Multistate input [MI]
Multistate output [MO]
Multistate calculated value [MCalcVal]
Multistate configuration value [MCnfVal]
Multistate process value [MPrcVal]
Third party objects which contain the required properties.

Refer to data point objects for a detailed description of the BACnet data points.

Required properties:

Present value
State flag

Optional properties:

Reliability
Update count

Hardware interrupt

This XFB supports hardware interrupts (OB trigger) for immediate response to specific events such as manual switching of lights. If the XFB is applied in a chart assigned to OB40 or OB41, OB triggering occurs automatically on interrupt signals from I/O modules.

Pin description (inputs)

BaObjRef
BA-Object reference Structure [BaObjRef] defines a bound connection between XFB and BACnet object. The binding occurs automatically. Manual configuration attempts are not necessary and can result in system errors.
DeviceId	Device identifier Double word (default value: 16#3FFFFF) [DeviceId] comprises object type and object instance in a single identifier. It is used to identify device object: local or remote. Local device object could also be identified by value 16#3FFFFF.
ObjectId	Object identifier Double word (default value: 16#3FFFFF) [ObjectId] comprises object type and object instance in a single identifier. It is used to identify object within a device.
ItemId	Item identifier Integer (default value: -1) [ItemId] represents an item index in the functional view node object, which references the BACnet object. [ObjectId] and [ItemId] together define an indirect access reference to the BACnet object. Value -1 indicates that direct binding is used.

EvlFnct
Evaluation function Integer (default value: 3) [EvlFnct] determines the type of operation performed on all valid present values.
1: Minimum	The smallest value is selected.
2: Maximum	The greatest value is selected.
3: Last updated (default)	The last updated value is selected. If more than one value is updated in the same cycle, the lowest index number is selected.
4: Ordered evaluation	Evaluation by a configurable order. (unavailable, included for future use)

Pin description (outputs)

PrVal
Present value Integer (default value: 1) The value resulting from the evaluation function performed on all valid aggregated member objects. This value is used to update the result object present value. If the result object is manually overridden to a new value, [PrVal] will display the new value. [PrVal] will deliver the last valid value if [Valid] = False. Note The default initial value for [PrVal] can be changed in CFC to a different value if necessary.

PrVal

Present value

Integer (default value: 1)

The value resulting from the evaluation function performed on all valid aggregated member objects. This value is used to update the result object present value.

If the result object is manually overridden to a new value, [PrVal] will display the new value. [PrVal] will deliver the last valid value if [Valid] = False.

Note
The default initial value for [PrVal] can be changed in CFC to a different value if necessary.

Valid
Valid Boolean (default value: False) An indication of whether output pin [PrVal] is reliable.
1 (True)	[PrVal] is reliable if at least one of the aggregated member objects is valid.
0 (False)	[PrVal] is not reliable if none of the aggregated member objects are valid.

Valid

Boolean (default value: False)

An indication of whether output pin [PrVal] is reliable.

1 (True)

[PrVal] is reliable if at least one of the aggregated member objects is valid.

0 (False)

[PrVal] is not reliable if none of the aggregated member objects are valid.

UpdInd
Update indication Boolean (default value: False) An indication of whether the Present value property for one of the aggregated member objects has been newly updated. When an update occurs, [UpdInd] toggles from 0 to 1 (True) and returns to 0 (False) on the next cycle (immediate). It is not possible to detect the toggle without an additional function block connected to [UpdInd] (for example, a counter function block). [UpdInd] will only be set to True if [Valid] is True. [UpdInd] uses the update count property if present. This makes it possible to recognize a value as having been updated in cases where the new value is the same as the previous value. For objects without update count, [UpdInd] toggles on a change to Present value. Note Placing the result object out of service does not affect [UpdInd] operation.

UpdInd

Update indication

Boolean (default value: False)

An indication of whether the Present value property for one of the aggregated member objects has been newly updated.

When an update occurs, [UpdInd] toggles from 0 to 1 (True) and returns to 0 (False) on the next cycle (immediate). It is not possible to detect the toggle without an additional function block connected to [UpdInd] (for example, a counter function block). [UpdInd] will only be set to True if [Valid] is True.

[UpdInd] uses the update count property if present. This makes it possible to recognize a value as having been updated in cases where the new value is the same as the previous value. For objects without update count, [UpdInd] toggles on a change to Present value.

Note
Placing the result object out of service does not affect [UpdInd] operation.

NumVals
Number of valid values Integer (default value: 0) The number of valid pesent values in the collection view node object.

NumVals

Number of valid values

Integer (default value: 0)

The number of valid pesent values in the collection view node object.

NumMbrs
Number of aggregated members Integer (default value: 0) The total number of member objects in the collection view node object.

NumMbrs

Number of aggregated members

Integer (default value: 0)

The total number of member objects in the collection view node object.

ErrCode
Error code indication Integer (default value: 20) The status of the last performance of the XFB read operation.
= 0	No error.
> 0	Error, see XFB error codes.

ErrCode

Error code indication

Integer (default value: 20)

The status of the last performance of the XFB read operation.

= 0

No error.

> 0

Error, see XFB error codes.

ErrWrit
Error while writing Integer (default value: 20) The status of the last performance of the XFB write operation to the result object.
= 0	No error.
> 0	Error, see XFB error codes.

ErrWrit

Error while writing

Integer (default value: 20)

The status of the last performance of the XFB write operation to the result object.

= 0

No error.

> 0

Error, see XFB error codes.

Use case examples

NOTICE

Note
Graphics reflect examples of XFB implementations; See ABT for current examples of CFC.

R_MX: Example taken from the HVAC air equipment fan CHT{FanMultiSpd01}. Due to graphical size limitations, function blocks may be missing or shown more closely grouped than is typical.