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Valid for S700
Table of Contents
Question
Is it possible to connect a safe output to the safe inputs (STO) of several servo amplifiers?
Validity
The information below applies to the following products:
Servo amplifier
| Manufacturer | Product designation | HWR |
|---|---|---|
| Kollmorgen | S701...S772 | 2.1 |
Safety controllers
| Manufacturer | Product designation | Product version |
|---|---|---|
| Pilz | PNOZ m0p base unit PNOZ m1p base unit PNOZ m2p base unit PNOZ m3p base unit PNOZ mo1p expansion module |
All |
Several switch-off paths can be operated in parallel on the safe 1-pole HL output of the aforementioned safety controllers. This is valid for up to 9 drives.
Safety analysis
A safety analysis has been carried out with regard to the switch-off paths and their controller. The effect of a random error in a switch-off path on the switch-off behavior of the whole arrangement has been investigated.
ATTENTION:
The user must ensure that a "Stuck-at-One" error cannot occur within the electrical installation in accordance with EN ISO 13849-2:2003, table D.5. A short circuit against the supply voltage would mean that none of the servo amplifiers in the parallel connection could be switched off.
Response times
Parallel connection has no effect on the specified response times.
Achievable safety level
Can Sil2 still be achieved? Does this change the characteristic data?
SIL2/PLd is achievable for the safety function STO with switch-off paths connected in parallel. The safety characteristic data in the current operating instructions is still valid.
Can Sil3 still be achieved?
Due to the specified test sequence for SIL3/PLe (independent tests on both switch-off paths for each servo amplifier), this safety level cannot be achieved with a parallel connection.
