Crankshaft Position Monitor (CPM)

This instruction applies to the Compact GuardLogix 5370, GuardLogix 5570, Compact GuardLogix 5380, and GuardLogix 5580 controllers.

The Crankshaft Position Monitor instruction is used to determine the slide position of the press by monitoring the Brake (BCAM), Dynamic (DCAM), and Takeover (TCAM) cams and representing the position as Top, Down, or Up by using the Slide Zone output. Also, the Top Zone, Down Zone, and Up Zone Boolean outputs are provided for monitoring and diagnostic purposes.

Available Languages

Ladder Diagram

Function Block

This instruction is not available in function block.

Structured Text

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WARNING:

This instruction is specified with the intent that the Slide Zone output is used to source the Slide Zone input of the Clutch Brake Inch Mode (CBIM), Clutch Brake Single Stroke Mode (CBSSM), Clutch Brake Continuous Mode (CBCM), and Camshaft Monitor (CSM) instructions.

Normal stop operation of a press begins when the slide enters the Top zone. A successful stop occurs when the press stops in the Top zone. During normal stopping, the speed of the press may cause the press to stop in the Down zone. This is called an overrun. To minimize this, the DCAM can be enabled to generate an early Top zone, allowing the press to begin stopping early.

WARNING:

When required, the DCAM should only be enabled for normal stopping, based on speed of the press. Do not adjust the DCAM to account for deteriorating brake performance.

WARNING:

WARNING:
Reversing the press should only be performed during set up mode by using the Clutch Brake Inch Mode (CBIM) instruction. Reversing the press is only permitted for moving the slide from the Down zone to the Top zone where the CBIM instruction automatically stops the press at Top. A fault occurs when reverse movement continues into the Up zone.

Operands

IMPORTANT:

Do not use the same tag name for more than one instruction in the same program. Do not write to any instruction output tag under any circumstances.

WARNING:

If you change instruction parameters while in Run mode, you must accept the pending edits and cycle the controller mode from Program to Run for the changes to take effect.

The following table provides the parameters used to configure the instruction. These parameters cannot be changed at runtime.

Operand	Data Type	Description
CPM	CB_CRANKSHAFT_POSITION_MONITOR	This parameter is a backing tag that maintains important execution information for each usage of this instruction. ATTENTION: To avoid unexpected operation do not reuse this backing tag and its members. Do not write to any of the tag members anywhere else in the program.
Cam Profile	BOOL	This parameter determines the cam profile used to generate the Slide Zone values. A (0) - See CPM – Cam Profiles and CPM – Normal Operation with Cam Profile A below. B (1) - See CPM – Cam Profiles and CPM – Normal Operation with Cam Profile B below.

The following table explains the instruction inputs. The inputs may be field device signals from input devices or derived from user logic.

Operand	Data Type	Description
Enable	BOOL	This signal is used to enable the Crankshaft Position Monitor (CPM) instruction. ON (1): The instruction outputs are enabled. OFF (0): The instruction outputs are disabled.
Brake Cam (BCAM)	BOOL	This input is sourced by the cam monitoring device (hard cam) or application logic (soft cam).
		Cam Profile A	This input specifies the overrun point and the Top zone when dynamic stopping is disabled. OFF (0) -> ON (1): While the press is running and dynamic stopping is disabled, this transition signals the end of the Up zone and the start of the Top zone. ON (1) -> OFF (0): While the press is stopping, this transition causes the Camshaft Monitor instruction to generate a brake fault.
		Cam Profile B	This input specifies the overrun point and the zone where immediate braking of the press is allowed. OFF (0) - No effect. OFF (0) -> ON (1): When detected while the press is stopping, this transition causes the Camshaft Monitor (CSM) instruction to generate a brake fault. While the press is running, this transition signals the end of the Top zone and start of the Down zone. ON (1) -> OFF (0): While the press is running, this transition must occur after the OFF (0) to ON (1) transition of the Takeover cam (TCAM).
Takeover Cam (TCAM)	BOOL	This input is sourced by the cam monitoring device (hard cam) or application logic (soft cam).
		Cam Profile A	This input is used to indicate the start of the Up zone. OFF (0) -> ON (1): This transition signals the start of the end of the Down zone and the start of the Up zone. ON (1) -> OFF (0: When dynamic stopping is enabled, this transition has no effect unless the dynamic stop signal has yet to occur. When this happens, this transition signals the end of the Up zone and start of the Top zone.
		Cam Profile B	This input is used to indicate the start of the Up zone. OFF (0): The press is considered to be in the Down zone when the Brake cam (BCAM) is ON (1). OFF (0) -> ON (1): This transition signals the start of the Up zone and the end of the Down zone and must occur before the ON (1) to OFF (0) transition of the BCAM. ON (1) -> OFF (0): When dynamic stopping is not enabled, this transition signals the end of the upstroke and the start of the Top zone. When dynamic stopping is enabled, this transition has no effect unless the dynamic stop signal has yet to occur. In this case, the dynamic stopping enable behavior is performed.
Dynamic Cam (DCAM)	BOOL	This input is used to generate an early top signal for fast-running presses. This input is sourced by a cam monitoring device (hard cam) or application logic (soft cam). This parameter is not safety-related.
		Cam Profile A	When dynamic stopping is not required, this input should be sourced by the inverse of the Brake Cam (BCAM). OFF (0) -> ON (1): Dynamic stopping is enabled when this transition occurs at or after the ON (1) to OFF (0) transition of the BCAM. ON (1) -> OFF (0): This transition signals the end of upstroke and the start of the Top zone when it occurs before the OFF (0) to ON (1) transition of the Takeover cam (TCAM).
		Cam Profile B	When dynamic stopping is not required, this input should be sourced by the Takeover Cam (TCAM). OFF (0) -> ON (1): Dynamic stopping is enabled when this transition occurs at or after the OFF (0) to ON (1) transition of the TCAM. ON (1) -> OFF (0): This transition signals the end of Up zone and the start of the Top zone when it occurs at or before the ON (1) to OFF (0) transition of the TCAM.
Input Status	BOOL	This input represents the combined status of the cam monitoring functions in addition to the I/O module status. ON: Inputs are valid. The Slide Zone status bit is set to 1. OFF: Inputs are invalid. All outputs are set to their de-energized or OFF (0) state. The Slide Zone status bit is set to 0.
Reverse	BOOL	Reversing the press should only be performed during set up mode by using the Clutch Brake Inch Mode (CBIM) instruction. Reversing the press is only permitted to move the slide from the Down zone to the Top zone where the Clutch Brake Inch Mode (CBIM) instruction automatically stops the press. A fault is generated when reverse movement is continued into the Up zone. OFF (0): Reverse operation is disabled. ON (1): When the slide is in the Down zone, this instruction lets the press move toward the Top zone. A fault is generated if this input is ON (1) when the slide is in the Up zone.
Press Motion Status	BOOL	This input represents the motion status of the press and is sourced by Output 1 of the Main Valve Control (MVC) instruction or other valve control application logic. OFF (0): The press has stopped or a stop request has been issued. ON (1): The press is running or a start request has been issued. Important: When the press has been requested to stop at Top, overrun monitoring is enabled when the slide transitions from the Up to the Top zone. An overrun fault occurs when the slide continues to move into the Down zone.
Reset⁽¹⁾	BOOL	This input clears the instruction faults provided the fault condition is not present. OFF (0) -> ON (1): The Fault Present and Fault Code outputs are reset.

⁽¹⁾ ISO 13849-1 stipulates instruction reset functions must occur on falling edge signals. To comply with ISO 13849-1 requirements, add this logic immediately before this instruction. Rename the “Reset_Signal” tag in this example to your reset signal tagname. Then use the OSF instruction Output Bit tag as the instruction’s reset source.

The following table explains the instruction outputs. The outputs may be field device signals or derived from user logic.

Operand	Data Type	Description
Slide Zone	DINT	This output represents the position of the slide and the position information status. This output is used to source the Slide Zone input of the Clutch Brake Inch Mode (CBIM), Clutch Brake Single Stroke Mode (CBSSM), Clutch Brake Continuous Mode (CBCM), and Camshaft Monitor (CSM) instructions. This is a bit-mapped value where: Bit 0: Status OFF (0) - The Slide Zone information is invalid. Prevents the energizing of Output 1 on an initial start or immediately de-energized Output 1. ON (1) - Slide Zone information is valid. Bits 1 and 2: Slide Zone The following table lists how Bits 0 through 2 are used to represent the valid slide zones.
		Bit 2	Bit 1	Bit 0	Slide Zone	Decimal Value
		0	0	1	Down	1
		0	1	1	Up	3
		1	0	1	Top	5
		Bits 3 through 31: Unused; Set to 0.
Top Zone (TZ)	BOOL	This information bit indicates when the slide is in the Top zone.
Down Zone (DZ)	BOOL	This information bit indicates when the slide is in the Down zone.
Up Zone (UZ)	BOOL	This information bit indicates when the slide is in the Up zone.
Diagnostic Code	DINT	This output indicates the diagnostic status of the instruction. See the CPM – Diagnostic Codes below for a list of diagnostic codes. This parameter is not safety-related.
Fault Code	DINT	This output indicates the type of fault that occurred. See the CPM – Fault Codes below for a list of fault codes. This parameter is not safety-related.
Fault Present (FP)	BOOL	ON (1): A fault is present in the instruction. OFF (0): The instruction is operating normally.

IMPORTANT:

Do not write to any instruction output tag under any circumstances.

Cam Profiles

This instruction supports two cam profiles, A or B, selected by using the Cam Profile configurable parameter. The main difference between Cam Profiles A and B is the configuration of the Brake Cam (BCAM). In profile A, the BCAM is configured to represent the Top zone and in profile B, it is configured to represent the Down zone. The Takeover Cam (TCAM) in both profiles is configured to represent the Up zone.

These profile diagrams illustrate the relationships of the cams when the Dynamic Cam (DCAM) is enabled.

When enabled, the DCAM is configured the same way, with the ON (1) to OFF (0) transition during the Up zone generating the early Top zone. Depending upon the speed of the press, this transition can be configured to occur anytime during the Up zone. However, when the DCAM is disabled, it must be configured as follows:

Profile A – The DCAM must be sourced by the inverse of the BCAM input source.

Profile B – The DCAM must be sourced by the TCAM input source.

WARNING:

Cam angles are not shown in these cam profiles. The cam angles should be selected by qualified personnel.

WARNING:

When the Cam Profile is configured for A and dynamic stopping is disabled, the Dynamic Cam (DCAM) input must be sourced inverse of the Brake Cam (BCAM) input source.

WARNING:

When the Cam Profile is configured for B and dynamic stopping is disabled, the Dynamic Cam (DCAM) input must be sourced by the Takeover Cam (TCAM) input source.

Normal Operation with Cam Profile A

The following example describes normal operation when Cam Profile A is selected and the press is moving in the forward direction. The press starts with the slide at Top with the Takeover cam input (TCAM) OFF (0) and the Brake cam input (BCAM) ON (1) at (A) The Slide Zone is set to Top. As the press moves, the BCAM input transitions from ON (1) to OFF (0) at (B) and the Slide Zone changes from Top to Down. As the press continues moving, the TCAM input transitions from OFF (0) to ON (1) at (C) and the Slide Zone changes from Down to Up. Further press movement causes the Slide Zone output to change from Up to Top at different points depending on the Dynamic cam input (DCAM) configuration.

When the DCAM is enabled, the Slide Zone changes from Up to Top when the DCAM input transitions from ON (1) to OFF (0) while the TCAM input is ON (1) at (D). When the DCAM is disabled, the Slide Zone changes from Up to Top when the BCAM input transitions from OFF (0) to ON (1) at (D).

Normal Operation with Cam Profile B

The following example describes normal operation when Cam Profile B is selected and the press is moving in the forward direction. The press starts with slide at Top with Takeover cam input (TCAM) and Brake cam input (BCAM) OFF (0) at (A) and Slide Zone set to Top. As the press moves, the BCAM input transitions from OFF (0) to ON (1) at (B) and the Slide Zone changes from Top to Down. As the press continues moving, the TCAM input transitions from OFF (0) to ON (1) at (C) and Slide Zone changes from Down to Up. Further press movement causes the Slide Zone output to change from Up to Top at different points depending on the Dynamic cam input (DCAM) configuration.

When the DCAM is enabled, the Slide Zone output changes from Up to Top when the DCAM input transitions from ON (1) to OFF (0) while the TCAM input is ON (1) and the BCAM input is OFF (0) at (D). When the DCAM is disabled, the Slide Zone output changes from Up to Top when the TCAM input transitions ON (1) to OFF (0) at (D).

False Rung State Behavior

When the instruction is executed on a false rung, all instruction outputs are de-energized.

Fault Codes and Corrective Actions

The fault codes are listed in hexadecimal format followed by decimal format.

Fault Code	Description		Corrective Action
00	No fault.		None.
16#20 32	The Input Status input transitioned from ON (1) to OFF (0) while the instruction was executing.		Check the I/O module connection or the internal logic used to source input status. Reset the fault.
16#1000 4096	While the press was moving forward, slide movement from the Top zone to the Up zone was detected.		Check the cams or the scan rate. Reset the fault.
16#1001 4097	While the press was moving forward, slide movement from the Down zone to the Top zone was detected.
16#1002 4098	While the press was moving forward, slide movement from the Up zone to the Down zone was detected.
16#1003 4099	While the press was moving forward, slide movement from the Up zone to the Down zone was detected.
16#1004 4100	Slide movement from the Top zone to the Down zone was detected while the press was reversing. Reverse movement is only permitted toward the Top zone.
16#1005 4101	Slide movement from the Down zone to the Up zone was detected while the press was reversing. Forward movement of the press is not permitted when Reverse is enabled.
16#1006 4102	The Dynamic cam (DCAM) is stuck OFF (0).		Check the DCAM. Reset the fault.
16#1007 4103	The Dynamic cam (DCAM) is stuck ON (1).
16#1008 4104	Cam Profile A	The DCAM turned OFF (0) while the slide was in the Down zone.
16#1008 4104	Cam Profile B	N/A
16#1009 4105	Cam Profile A	The Takeover cam (TCAM) is stuck ON (0).	Check the TCAM. Reset the fault.
16#1009 4105	Cam Profile B	N/A	Check the TCAM. Reset the fault.
16#100A 4106	Cam Profile A	N/A	Check the BCAM. Reset the fault.
16#100A 4106	Cam Profile B	The Brake cam (BCAM) is stuck ON (0).	Check the BCAM. Reset the fault.
16#1020 4128	A request to reverse the press was made while the slide was in the Up zone.		Set the Reverse input to OFF (0). Reset the fault.
16#1040 4160	A slide overrun fault occurred.		Check the brake linings for wear. Check the cam settings for proper alignment. Reset the fault.

Diagnostic Codes and Corrective Actions

The diagnostic codes are listed in hexadecimal format followed by decimal format

Fault Code	Description	Corrective Action
00	No fault.	None.
16#20 32	The Input Status input was OFF (0) when the instruction started.	Check the I/O module connection or the Camshaft Monitor (CSM) instruction used to source input status. Set the Input Status input to ON (1), if the inputs are not being sourced by a safety I/O module.

Affects Math Status Flags

Major/Minor Faults

None specific to this instruction. See Index Through Arrays for array-indexing faults.

Execution

Condition/State	Action Taken
Prescan	Same as Rung-condition-in is false.
Rung-condition-in is false	The .TZ, DZ, UZ, and FP is cleared to false. The Diagnostic Code, Fault Code, and Slide Code are set to 0.
Rung-condition-in is true	The instruction executes as described in the Normal operation section.
Postscan	Same as Rung-condition-in is false.

Metal Form Instructions

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