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Safety Function: Door Locking and Monitoring
6. Click Output Configuration and configure the module as shown.
Typically, contactor coils (outputs 0 and 1) do not react to the pulse testing of the output wires. If using a contactor
that does react to the pulse test, then disable the pulse testing. This should not affect the overall safety rating if
redundancy and monitoring are being used. Output 7 is the TLS3-GD2 locking solenoid.
7. Click OK.
Programming
The Dual Channel Input Stop with Test and Lock (DCSTL) instruction monitors and locks dual channel safety devices
whose main function is to stop a machine safely, for example, a safety gate with locking solenoid. When the unlock request
goes to 1 (high), the DCSTL instruction waits for the Hazard Stopped input to go to 1 (high), and then turns on the ULC
(unlock command) output. At the same time, the output (O1) goes to 0 (low) to indicate that the gate is no longer
protecting the hazard. The Lock Feedback should go to 0 (low), indicating the gate is indeed unlocked. The operator can
now open the gate. The DCSTL requires that the door monitors (channel A and channel B) cycle at this time or a fault
occurs when a restart is attempted. This cycle can be done by opening or closing the gate, or it can be done in software, as
shown later in this section.
In this example, the unlock request is generated by placing a demand on the safety interlock being controlled by the Dual
Channel Input Stop (DCS) instruction. For this application, all that is required is that the unlock request be set to 0 (low).
The demand on the safety interlock drops out the safety contactors, and five seconds later the Hazard Stopped tag is set to
1 (high). This causes the DCSTL instruction to set the ULC output, which energizes output 7 and unlocks the gate.
IMPORTANT
The requirements of your application determine the proper way to generate the Hazard Stopped tag.
There are two lock monitoring contacts on the TLS3-GD2 switch, yet there is only one lock feedback tag required for the
DCSTL instruction. The Dual Channel Input Monitor (DCM) instruction is used to monitor both lock contacts, and its
output is used for the DCSTL Lock Feedback tag.
The DCSTL, DCM, and DCS instructions monitor their respective dual-channel inputs for consistency (Equivalent Active High) and detect faults when the inconsistency is detected for longer than the configured Discrepancy Time (ms)
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Rockwell Automation Publication SAFETY-AT061C-EN-P - December 2014