What is the B10/B10d value of Harmony XB4/XB5 of Estop push button?
1. Why you need to know
For a Harmony XB4 or XB5 emergency stop push button, B10d = 1,500,000 operations. This is derived from the B10 of the complete push button, which is 300,000 operations: the emergency stop operator has a B10 of 300,000 cycles and the contact block a B10 of 1,000,000 cycles at nominal current AC-15 (230 V, 2 A), and the complete device takes the lower of the two. Because 20 % of failures are assumed to be dangerous for an emergency stop, B10d = B10 / 0.2, giving 1,500,000. Use the complete assembly figure, not the operator alone, in an ISO 13849-1 calculation.
2. How B10 and B10d are defined
B10 is the number of operations at which 10% of the population of components has failed.
B10d is the same measure but considering only dangerous failures - ie for emergency stop devices that could cause failure of the safety function.
- 𝑩𝟏𝟎 (𝑬𝒎𝒆𝒓𝒈𝒆𝒏𝒄𝒚 𝒔𝒕𝒐𝒑 𝒑𝒖𝒔𝒉𝒃𝒖𝒕𝒕𝒐𝒏)=𝐦𝐢𝐧{(𝑩𝟏𝟎(𝑬𝒎𝒆𝒓𝒈𝒆𝒏𝒄𝒚 𝒔𝒕𝒐𝒑 𝒉𝒆𝒂𝒅),𝑩𝟏𝟎(𝒄𝒐𝒏𝒕𝒂𝒄𝒕 𝒃𝒍𝒐𝒄𝒌)}
- 𝑩𝟏𝟎 (𝒄𝒐𝒏𝒕𝒂𝒄𝒕 𝒃𝒍𝒐𝒄𝒌) corresponds to the contact electrical endurance and depends on the utilization category, operating voltage, and switching current.
- 𝑩𝟏𝟎 (𝑬𝒎𝒆𝒓𝒈𝒆𝒏𝒄𝒚 𝒔𝒕𝒐𝒑 𝒉𝒆𝒂𝒅) corresponds to the head mechanical endurance and is specified under standard operating conditions.
- 𝑩𝟏𝟎𝒅( 𝑬𝒎𝒆𝒓𝒈𝒆𝒏𝒄𝒚 𝒔𝒕𝒐𝒑 𝒑𝒖𝒔𝒉𝒃𝒖𝒕𝒕𝒐𝒏)=𝑩𝟏𝟎(𝑬𝒎𝒆𝒓𝒈𝒆𝒏𝒄𝒚 𝒔𝒕𝒐𝒑 𝒑𝒖𝒔𝒉𝒃𝒖𝒕𝒕𝒐𝒏)/𝑭
- F is the ratio between dangerous failures and total failures. For Harmony XB4/XB5 emergency stop pushbuttons, F=0.2.
3. Reference values for Harmony XB4 / XB5 emergency stop push buttons
| Parameter | Value | Conditions and derivation | Commercial reference |
| B10 (Emergency stop head) | 300,000 operations | Standard operating conditions | ZB4BS844 |
| B10 (contact block) | 1,000,000 operations | AC15, 2A at 230VAC, operating frequency < 3600 cycles/hour, duty cycle = 0.5 DC13, 0.5A at 24VDC operating frequency < 3600 cycles/hour, duty cycle = 0.5 | ZBE102 (NC contact block) |
| B10 (Emergency stop pushbutton) | 300,000 operations | - | Complete unit : XB4BS8444 or complete control station with complete unit : XALK178F Sub-assemblies: ZB4BS844 head + ZB4BZ104 or ZB4BZ1045 body |
| B10d (Emergency stop pushbutton) | 1,500,000 operations | - | Complete unit : XB4BS8444 or complete control station with complete unit : XALK178F Sub-assemblies: ZB4BS844 head + ZB4BZ104 or ZB4BZ1045 body |
4. Related references
| Type | Commercial reference | Description |
| Complete unit | Emergency stop switching off, metal, red mushroom 40mm, Ø22,trigger turn to release, 2NC screw clamp terminals | |
| Control station with complete unit | Control station, plastic, yellow lid, 1 red mushroom push button Ø40, turn to release, 2NC screw clamp terminals | |
| Head | Emergency stop head, switching off, metal, red mushroom Ø40, Ø22, trigger turn to release | |
| Body | 2 NC contact blocks screw clamp terminals with metal fixing collar | |
| Contact | Single NC contact block screw clamp terminals |
Note1 : Those products are also available in plastic versions through XB5 range.
Note2 : Emergency stop head and complete units are also available in other head diameters and types, and with key.
Launch Product Selector on se.com to configure a Harmony selector switch according to your requirements or contact Schneider Electric Technical Support to check a configuration against your control scheme.