Safe test arrangement
A flexible test arrangement for performing measurements on a test object. A plurality of safety components, each having a safety module which can be set to active or inactive, and having a ready status which can be set to active or inactive, is provided in a circular test arrangement. Each of the safety components carries out a number of function tests cyclically. As one of the function tests, a cyclical, error-free reception of a data packet is tested. One of the safety components is selected as a bus master which cyclically transmits a bus verification signal in a data packet to the safety component which is adjacent in the direction of transmission, wherein the bus verification signal is relayed by each of the safety components in a data packet, and, when said bus verification signal is received in a data packet, the bus master determines that the circular test arrangement is closed.
1. A method for operating a test arrangement comprising:
a plurality of safety components, each of the plurality of safety components having a signal input for receiving data packets, and a signal output for transmitting data packets, a safety module settable to active or inactive, and a ready status settable to active or inactive,
wherein the safety module of a respective safety component is set to inactive when an associated safety component has an inactive ready status,
wherein the signal inputs and signal outputs of the plurality of safety components are connected in such a way that the plurality of safety components form a circular test arrangement with a direction of transmission for the data packets,
wherein each of the plurality of safety components cyclically carry out a number of function tests and set their ready status to active when the number of function tests is successful and to inactive if at least one of the function tests fails,
wherein one of the function tests is checking for a cyclic, error-free reception of a data packet,
wherein one of the plurality of safety components is selected as the bus master, which cyclically transmits a bus verification signal in a data packet to an adjacent safety component in the direction of transmission, and each of the remaining safety components are configured to forward the bus verification signal in the packet to an adjacent safety component, and
wherein the bus master, upon receipt of the bus verification signal in the data packet, determines that the circular test arrangement is closed.
2. The method according to claim 1 , wherein the bus master, upon determining that the circular test arrangement is closed, cyclically checks whether its ready status is active and, if when the ready status is active, transmits a ready signal in a data packet to the adjacent safety component, and
wherein the plurality of safety components, upon receipt of the ready signal, each check whether their ready status is active, and, if when the ready status is active, transmit a ready signal in a data packet to the adjacent safety component in the direction of transmission.
3. The method according to claim 2 , wherein the bus master, upon receipt of the ready signal, determines that the test arrangement is operational, and transmits an activation signal in a data packet to the adjacent safety component in the direction of transmission,
wherein the plurality of safety components, upon receipt of an activation signal, each activate their safety module, and forward the activation signal in a data packet.
4. The method according to claim 3 , wherein the bus master, after transmitting a ready signal and not receiving a ready signal, transmits an emergency stop signal in a data packet to the adjacent safety component in the direction of transmission,
wherein the plurality of safety components each deactivate their safety module upon receipt of the emergency stop signal, and forward the emergency stop signal in a data packet.
5. The method according to claim 1 , wherein the bus master, after transmitting the bus verification signal and not receiving a bus verification signal, transmits an emergency stop signal in a data packet to the adjacent safety component in the direction of transmission,
wherein the plurality of safety components each deactivate their safety module upon receipt of the emergency stop signal, and forward the emergency stop signal in a data packet.
6. The method according to claim 1 , wherein the plurality of safety components carry out a safety test, and when the safety test fails, the respective safety components deactivate their ready status, and transmit an emergency stop signal in a data packet to the adjacent safety component in the direction of transmission,
wherein the plurality of safety components deactivate their safety module upon receipt of the emergency stop signal, and transmit the emergency stop signal in a data packet.
7. The method according to claim 1 , wherein the bus master is selected via a component identification of the plurality of safety components.
8. The method according to claim 1 , wherein the plurality of safety components transmit a component identification with the bus verification signal in the data packet, and
wherein the bus master identifies the plurality of safety components by the component identifications received with the bus verification signal.
9. The method according to claim 8 , wherein the bus master transmits the component identifications back to the respective safety components in a data packet, and a safety component sets its ready status to inactive if it does not receive its identification back from the bus master.
10. The method according to claim 7 , wherein a safety component with the lowest component identification is selected as the bus master.