FB_CAMMONITOR

Description Function Block

The FB_CAMMONITOR function block is used to implement an electronic cam group. In addition to excentric mode, pendulum mode is also supported.

Excentric mode:
Only one direction of rotation is permitted in excentric mode.
A check is performed to make sure that the position stops after one cycle at the latest after the upper reversal point (TDC: Top Dead Center) plus maximum overrun (OverrunMax). OverrunTDC outputs the current overrun or the current position after TDC.
The lower reversal point (BDC: Bottom Dead Center) is specified with a lower and upper limit. After the BDC is exceeded, the press is in upward movement. This information is output at the bUpwardsMove output.
If the press comes to a standstill without having reached or exceeded TDC again or if the direction of rotation is reversed, then the bCamMonOK output is immediately set to FALSE.
After standstill is reached, a new cycle is permitted only after a falling edge is detected at the bReset input.
The bBackwardsMove input is used to notify the function block that a backward movement of the press is permitted. This is permitted only if the position is between TDC1UpperLimit and BDCLowerLimit. The backward movement ends when TDC1UpperLimit is reached.
In excentric mode, an upward cam can be connected to the bUpwardCAM input and an overrun cam can be connected to the bOverrunCAM input. If the bUpwardCAM input is active, then a check is performed to verify that the upward cam is set after BDC and reset again at 0°. If the bOverrunCAM input is active, then a check is performed to make sure that the overrun cam is set after TDC1LowerLimit and remains set while the press is in standstill. The overrun cam may be reset only after the next cycle is started. A backward movement of the press is permitted only if the bUpwardCAM and bOverrunCAM inputs are FALSE. The backward movement ends when the bOverrunCAM input becomes TRUE.
Pendulum mode:
Both directions of rotation are permitted in pendulum mode. Two upper reversal points (TDC: Top Dead Center) are specified here.
Because the curve with which the press is supposed to be driven can or must be modified for each product, the maximum range of the pendulum stroke is set for the limits of both TDCs.
A check is performed to make sure that TDC1 and TDC2 are never exceeded. If this happens anyway, then the bCamMonOK output is set to FALSE. At the start of the cycle (falling edge at the bReset input), the press may start with any movement (pulsating, reverse, etc.) until the BDC is reached. After that, only the upward movement is permitted. The upward movement is output as a signal at the bUpwardsMove output.
The lower reversal point (BDC: Bottom Dead Center) is specified with a lower and upper limit.
A restart is enabled via the bReset input. If the press is moving in the downward direction without a falling edge being detected at the bReset input, then it is stopped immediately by setting the bCamMonOK output to FALSE.
The optional bUpwardCAM and bOverrunCAM inputs for connecting an upward cam and an overrun cam are not supported in pendulum mode. If they are active by mistake, then an error is set.

`FB_CAMMONITOR`

The FB_CAMMONITOR provides the user with a safe evaluation module which can safely output the cams (bTDC, bBDC, and bUpwardsMove) according to the set fixed values and depending on the current position.

Function block output: `bUpwardsMove`

The bUpwardsMove output provides the user with the information that the press is in upward motion after passing BDC. This signal can be used for muting light curtains, for example, or transferring control commands to the press.

Position detection of the press

Position detection must be implemented according to the required SIL or performance level. The user or machine manufacturer must prove that this condition has been fulfilled.

The position value must be verified reliably, for example from several analog values or it must be made available to the function block in another safe way. The first can be implemented, for example, by means of the COMPARE function block. In addition, the bPressStarted input can be used to generate an expectation. In this case, the demand of a movement is communicated to the function block. Then the function block monitors that a change of position also occurs within the set parameters.

Excentric mode / pendulum mode

For excentric mode, the bExcentricMode input is set and the TDC2UpperLimit and TDC2LowerLimit inputs must be inactive or 0.

The bPendulumMode input is set for pendulum mode and the TDC2UpperLimit and TDC2LowerLimit inputs must be active and not equal to 0.

EL6900

The FB_CAMMONITOR function block is not supported by the EL6900.

Table 34. VAR_INPUT

Name	Data Type	Initial Value	Description, Parameter Values
`bAutomatic`	`SAFEBOOL`	`FALSE`	`FALSE`: Normal mode `TRUE`: Automatic mode (no parameter check)
`bSettingMode`	`SAFEBOOL`	`FALSE`	Parameter transfer in setup mode If the input is set to `TRUE`, then it is possible to change internal parameters.
`Position`	`UDINT`	`0`	Press position: The position value must be verified reliably, for example from several analog values or it must be made available to the function block in another safe way according to the required SIL or performance level. Permitted data types: `UINT`, `UDINT`
`bReset`	`BOOL`	`FALSE`	Reset input: A falling edge must be detected at the `bReset` input before each press start. A movement may take place or the TDC exited only after that.
`bPressStarted`	`BOOL`	`FALSE`	If the input is active, then a movement or change of position is expected for a logic 1 at the input. To do this, the `tPressStartDelayTime`, `tMoveDetectionTime`, and `udiMinPositionChange` parameters must be set.
`udiMaxPosition`	`SAFEUDINT`	`0`	Maximum permitted position value during a 360° movement of the press. Only a constant value is permitted (no variable).
`TDC1LowerLimit`	`UDINT`	`0`	Eccentric mode: Lower limit of the upper reversal point (TDC: Top Dead Center). This is located at the left of the upper reversal point. Pendulum mode: Lower limit of the upper reversal point in the left half of the press. The value must be greater than the lower reversal point and less than `TDC1UpperLimit`. Permitted data types: `UINT`, `UDINT` Constant value and variable permitted.
`TDC1UpperLimit`	`UDINT`	`0`	Excentric mode: Upper limit of the upper reversal point. This is located at the right of the upper reversal point. Pendulum mode: Upper limit of the upper reversal point in the left half of the press. The value must be greater than TDC1LowerLimit and less than udiMaxPosition. Permitted data types: `UINT`, `UDINT` Constant value and variable permitted.
`TDC2LowerLimit`	`UDINT`	`0`	Excentric mode: Not used Pendulum mode: Lower limit of the upper reversal point in the right half of the press. The value must be greater than `TDC2UpperLimit` and less than `BDCLowerLimit`. Permitted data types: `UINT`, `UDINT` Constant value and variable permitted.
`TDC2UpperLimit`	`UDINT`	`0`	Excentric mode: Not used Pendulum mode: Upper limit of the upper reversal point in the right half of the press. The value must be greater than 0 and less than `BDCLowerLimit`. Permitted data types: `UINT`, `UDINT` Constant value and variable permitted.
`BDCLowerLimit`	`UDINT`	`0`	. Lower limit of the lower reversal point Excentric mode: Must be less than `udiMaxPosition / 2` and greater than `OverrunMax`. Pendulum mode: Must be less than `udiMaxPosition / 2` and greater than `TDC2LowerLimit`. Permitted data types: `UINT`, `UDINT` Constant value and variable permitted.
`BDCUpperLimit`	`UDINT`	`0`	. Upper limit of the upper reversal point Excentric mode: Must be greater than `udiMaxPosition / 2` and less than `TDC1LowerLimit`. Pendulum mode: Must be less than `udiMaxPosition / 2` and greater than `TDC1LowerLimit`. Permitted data types: `UINT`, `UDINT` Constant value and variable permitted.
`OverrunMax`	`UDINT`	`0`	Excentric mode: `OverrunMax` indicates the position where the press must have stopped at the latest in excentric mode. If this value is exceeded without the press stopping, then the `bCamMonOK` output is set to `FALSE`. The `OverrunMax` input must be greater than `TDCUpperLimit` and less than `BDCLowerLimit`. Pendulum mode: Not used Permitted data types: `UINT`, `UDINT` Constant value and variable permitted.
`bBackwardsMove`	`SAFEBOOL`	`FALSE`	Excentric mode: With this input, the press can be moved in the backward direction. This is possible until `TDC1UpperLimit` is reached. Pendulum mode: Not used
`bOverrunCAM`	`SAFEBOOL`	`FALSE`	Excentric mode: Optional. An overrun cam can be connected here. A check is performed to make sure that the overrun cam is set after TDC and remains set while the press is in standstill. The overrun cam may be reset only after the next cycle is started. Pendulum mode: Not used
`bUpwardCAM`	`SAFEBOOL`	`FALSE`	Excentric mode: Optional. An upward cam can be connected here. A check is performed to make sure that the cam is set to BDC and reset at 0°. Pendulum mode: Not used
`bExcentricMode`	`SAFEBOOL`	`FALSE`	`TRUE`: Excentric mode: Only one direction of rotation is permitted. Only one of the `bExcentricMode` and `bPendulumMode` inputs may be `TRUE`. Only a constant value is permitted (no variable)
`bPendulumMode`	`SAFEBOOL`	`FALSE`	`TRUE`: Pendulum mode. Both directions of rotation are permitted. Only one of the `bExcentricMode` and `bPendulumMode` inputs may be `TRUE`. Only a constant value is permitted (no variable)
`udiMinPositionChange`	`SAFEUDINT`	`0`	If the `bPressStarted` input is active, then a value must be specified to indicate the minimum change of position within `tMoveDetectionTime`.
`tAllowedPositionJitter`	`UINT`	`0`	Permitted jitter (in ms) for position in standstill Only a constant value is permitted (no variable)
`tMoveDetectionTime`	`SAFETIME`	`TIME#0ms`	If the `bPressStarted` input is active, then the time must be specified after which the position must change when a motion has been detected for the first time.
`tPressStartDelayTime`	`SAFETIME`	`TIME#0ms`	If the `bPressStarted` input is active, then the time must be specified here after which a movement must be detected when `bPressStarted` has a positive edge.
`tStopDetectionTime`	`SAFETIME`	`TIME#0ms`	Time frame (in ms) for the standstill detection where the position can move only by the value `tAllowedPositionJitter`. Because the position is usually received via a TwinSAFE connection, its value will not change in each cycle. Only a constant value is permitted (no variable)

Table 35. VAR_OUTPUT

Name	Data Type	Initial Value	Description, Parameter Values
`bTDC`	`SAFEBOOL`	`FALSE`	`TRUE`: The current position is located between `TDC1LowerLimit` and `TDC1UpperLimit` or between `TDC2LowerLimit` and `TDC2UpperLimit`.
`bBDC`	`SAFEBOOL`	`FALSE`	`TRUE` when the current position is located between `BDCLowerLimit` and `BDCUpperLimit`.
`bCAMMonOK`	`SAFEBOOL`	`FALSE`	`TRUE` when all internal checks do not result in any errors. After starting the group where the function block is programmed, `bCAMMonOK` is set for the first time after a falling edge at the `bReset` input.
`bUpwardsMove`	`SAFEBOOL`	`FALSE`	Excentric operation: `TRUE`: The press is in an upward motion. The position is between `BDCUpperLimit` and 0°. Pendulum mode: Depending on which half the movement was started, the output is set in the other half. The output is set from `BDCUpperLimit` or `BDCLowerLimit` until the standstill of the press is detected.
`OverrunTDC`	`SAFEUINT`	`0`	Eccentric operation: Difference between `TDC1LowerLimit` and the current position. Pendulum mode: Not used
`OverrunStop`	`SAFEUINT`	`0`	Difference between the position on the falling edge at `bPressStarted` and the current position.
`bError`	`SAFEBOOL`	`FALSE`	`TRUE`: Parameter error Movement error Error with active `bPressStarted` input Error with upward cam (excentric mode only) Error with overrun cam (excentric mode only) Error when starting and stopping in TDC (excentric mode only) `FALSE`: No error has occurred.

FB_CAMMONITOR

Description Function Block

FB_CAMMONITOR

Function block output: bUpwardsMove

Position detection of the press

Excentric mode / pendulum mode

EL6900

`FB_CAMMONITOR`

Function block output: `bUpwardsMove`