Welcome to the presentation about safety functions of ACS880 functional safety, FSO- 12 Safety functions module.

Transcription

1 Welcome to the presentation about safety functions of ACS880 functional safety, FSO- 12 Safety functions module. 1

2 Here is a list of the FSO-12 supported safety functions and example applications they support. (Function Application) For example: Safe stop 1 (SS1) is used for safe process stops and for end of travel ramp stop. Safe process stop brings the drive to zero speed safely End of travel ramp stop is used, e.g., in crane applications Safely-limited speed (SLS) is used for safe crawl speed for specific work cycles, e.g., conveyor belts, allowing user a longer reaction time in case of an unwanted incident. Safe maximum speed (SMS) ensures that structural speed is not exceeded. In the case of wrong references, it keeps the drive within safe speed limits Safe outputs indicate safety functions status and actuate auxiliary devices. Outputs can be configured to become active when some safety functions are activated 3

3 Safe torque off function definition. (EN IEC ) According to the standard definition, the STO stops the power that can generate torque from traveling to the motor. It does not mean that the drive is physically separated from the motor and thus it can be done electronically. Note 1 and note 2 explain that STO corresponds to an uncontrolled stop in accordance with stop category 0. Furthermore, this safety function may be used where power removal is required to prevent an unexpected start-up. After STO is activated, modulation of the motor stops and speed begins to decrease. (Motor coasts to stop.) STO is a drive function and is accompanied by the drive itself: yet, emergency stop can be implemented without the drive. STO is not a suitable function to use when performing electrical maintenance to the motor, since the motor and cables can still have voltage. (Power off -contactor switch is necessary.) 4

4 About STO details: STO can be used for Emergency Stop (cat. 0) and Prevention of Unexpected Start-up. To prevent the drive from starting, the system requires an additional resettable relay or switch that locks the drive. STO does not disconnect the machine from the power supply. Even if STO is active, high voltages may still remain. An additional main switch is required for disconnecting the drive from mains power supply. If the STO has a redundant structure, it eliminates the need for 2 contactors. 5

5 Safe Stop Emergency (SSE) is an emergency stop function that stops the motor with continuous brakes. Motor speed decreases linearly to zero speed. SSE can be selected to perform as an STO with category 0 or SS1 with category 1. When SS1 is used, a specific emergency stop ramp setting is required, STO activation needs to be set either as a time delay based or ramp monitoring (0-speed) based. SSE can be optionally activated by internal faults. SSE is not a standard IEC function, it is specific to ABB. 6

6 Definitions for Safe Stop 1 (SS1) and Safe Stop Emergency (SSE, cat. 1). The power drive system (PDS(SR)) provides three options: The drive initiates and controls the motor deceleration. It initiates the STO function when the motor speed is below a specified limit. An active safety control that controls deceleration is used. The drive initiates and monitors the deceleration. It initiates the STO function when the speed is below a limit. (Control unsafe, monitoring needed.) The drive initiates the deceleration and initiates the STO function after an application specific time delay. Without ramp monitoring the motor speed could reach negative values if the time delay is set too long. The monitoring prevents this situation from happening: STO is activated when the ramp limit is breached. This safety function corresponds to a controlled stop in accordance with stop category 1 of EN IEC The safety functions module can be configured to either use the time delay or the ramp monitor. This slide applies to SSE only if the function is configured to perform a delayed STO activation, either by monitoring time or ramp. 7

7 Safe Stop 1 (SS1) details. Safe stop 1 function can be used for Emergency Stop category 1 (= SSE). SS1 has two optional operating modes: 1. Time delay based STO activation. 2. Ramp monitoring (0-speed) based STO activation. (More efficient since it also includes time delay based STO activation.) 8

8 Here is a functionality cycle example of SS1. The cycle contains eight (8) steps from zero (0) to seven (7). The cycle begins from drive running normally and ends when the drive has returned back into normal operation. The ramp stopping system includes the drive, a motor, an emergency stop switch, a reset button for resetting emergency stop and a start button for the drive. 9

9 The drive unit consists of a control unit and an FSO-module, mounted on top of the control unit. The FSO-module interfaces with emergency stop button and a reset button, while the start button is connected straight to the control unit of the drive. This is stage 0. The drive is running and the safety function is in stand by, speed is stable. 10

10 Stage 1. The user presses the Emergency stop button a safety function request is sent to the FSO. The circuit is interrupted and the safety module notices that a safety stop was initiated. The drive is still running. 11

11 Stage 2. The safety module sends a request to the drive for the ramp function: A ramp stop is required. SS1 starts to internally monitor decreasing frequencies. STO is not yet active and the drive is still running. 12

12 Stage 3. The drive receives the ramp stop request and will run without the safety related function while the safety module is monitoring that safe ramping is started. The FSO will start monitoring according to its configuration, time delayed or ramp monitored. Frequency and speed are decreasing. 13

13 Stage 4. When the time delay has elapsed or zero speed has been reached, the STO is activated and the circuit is opened: Drive output is disabled. The FSO is controlling the drive. Nothing is preventing the control unit from doing something unexpected. The FSO always controls the output of the drive with the STO and is able to bring the drive to a safe state regardless of the control unit. 14

14 Stage 5. Safe state: The FSO does not allow the drive or motor to start by controlling the drive output. (Similar to Prevention of Unexpected Start-up mode.) The emergency stop button is down. 15

15 Stage 6. Resetting the drive. Emergency stop is pulled up and the E-stop input is deactivated. If the FSO is configured to require a manual acknowledgement, the reset button is pushed down to reset the function. Simultaneously STO will be deactivated. The drive is not yet restarting. 16

16 Final stage: When the start button is pressed, the drive returns to normal operation. 17

17 This slide illustrates Safe Brake Control, SBC. The SBC safety function s output includes a feedback. The function always has a redundant connection, feedback using one channel. The feedback comes from the brake relay or directly from brake contacts. In case the feedback indicates the brake cannot be opened, the device activates safe torque off. SBC works together with STO: Speed level activation means that SBC is activated when speed crosses the 0-speed limit. Time based activation means that SBC can be configured to activate before or after the STO. 18

18 The next two slides define the Safely-Limited Speed (SLS) function. The SLS function prevents the motor from exceeding the specified speed limit. SLS is activated from an input. For example, if machine maintenance is required when motor is running with a crawl speed. In the case of this figure, an SLS activation request is given when motor speed is above a specified speed limit. User can configure the speed monitoring to be started immediately when SLS activation request is given or, as shown in the figure, after a time delay during which drive can ramp down below the given the speed limit. If the speed exceeds the given limit when speed monitoring is active, Safe Stop Emergency SSE is activated. 19

19 Safely-Limited Speed (SLS) uses encoderless frequency estimation for estimating speed. One individual speed limit can be configured in SLS. SLS limits can be different in different directions. 20

20 The Safe Maximum Speed function, SMS, is similar to SLS function. It is activated in the configuration. It does not have to be triggered separately. It monitors the maximum allowed speed. The SMS function is not included in the status LED indications. (The function is constantly active in the background and is triggered if speed exceeds allowed maximum speed.) SMS is not a standard IEC function, it is specific to ABB. 21

21 The POUS function prevents the machine from starting accidentally. Here is how it functions. 1. The user stops the motor. 2. The user activates the POUS function. The FSO module activates the drive STO function and starts a counter for delay A. Note: If the user activates the POUS function when the motor is running, the FSO module activates the drive STO function, the motor coasts to a stop and the FSO module generates a fault. POUS is not supposed to be activated when the motor is running. 3. After the POUS delay for completion timer (A) has elapsed, the POUS completed indication becomes active. 4. The user removes the POUS request. The POUS completed indication is deactivated. 5. The user acknowledges the POUS function. The POUS active indication is removed. The FSO module deactivates the drive STO function and the user can restart the motor. 6. The user starts the motor. See the manual for more details. 22

22 The module s safe outputs can be used to indicate active safety functions or to control external devices. Safety function indications are selected during the configuration of the drive and module. 23

23 There is a brochure and a user s manual for further information on the FSO-12 safety functions module. 24

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