E-Stop manual reset button

danharding

Member
Join Date
Mar 2014
Location
UK
Posts
3
Hi guys just wondering if anyone new what colour an illuminated e-stop reset push button can be?

I have generally done manual reset circuits with an illuminated push button that lights up when the E-Stop relay has been reset so the system is safe and the machine can be started normally using another "start cycle" push button.

I have always used green in the past
But now we have nice LED push buttons I'm thinking of changing this to white but struggling to find any rules/regs/guidelines that state it needs to be a certain colour.

cheers in advance Dan
 
Hmm. Since you're in the UK, this isn't really any help but I usually use blue for an unilluminated reset button. This is an allowable color under NFPA 79. I think IEC 60204 is similar. EN/IEC 60947-5-5, EN/IEC 60204-1, and EN ISO 13850 all talk about the e-stop button itself but I haven't seen mention of a specific e-stop reset button color.
 
Yes I'm unable to find any info on the reset button, lots on the E-Stops though.

Like I say only used green before as all previous companies I've worked for have used that.

Quite happy to use blue though.

Donnchadh have you any info on the CE marking stating it need's to be blue, as I'm also installing CE marked machines made by a German company that have a non illuminated white button on there's??

Dan
 
there are several documents in the UK that document control panrels, wiring, safety requirements, risk assessments, and push button colors.

It's been oven 10 years since i read those manuals where i worked.

sorry, i can't remember their names, but it is in the regs for the eu certification.

regards,
james
 
EN 60 204-1 - I'm feeling rather Blue...

Hi Dan,

Welcome to the Forum...

Recommended colour coding acc. to EN 60 204-1

1. Colours

Pushbutton actuators must be marked with 2 colours in accordance with table 2.

Colours for START/ON actuators should be WHITE, GREY or BLACK, preferably WHITE. GREEN is also permitted. RED must NOT be used.

RED must be used for actuators provided for stopping in an emergency situation and for switching off in an emergency situation.

Colours for STOP/OFF actuators should be BLACK, GREY or WHITE, preferably BLACK. GREEN must NOT be used. RED is also permitted, however, it is recommended to avoid RED in the vicinity of components provided for emergency actions.

WHITE, GREY or BLACK are the preferred colours for pushbutton actuators with alternating START/ON and STOP/OFF function. RED, YELLOW or GREEN must not be used.

WHITE, GREY or BLACK are the preferred colours for pushbutton actuators initiating a function while being pressed and stopping the function when released (e.g. inching operations). RED, YELLOW or GREEN must not be used.

Resetting pushbuttons must be BLUE, WHITE, GREY or BLACK. In those cases where they also perform a STOP/OFF function, the preferred colours are WHITE, GREY or BLACK, with BLACK being the first choice. GREEN must NOT be used. (<<<Take note Dan!)


Table 2: Colours for pushbutton actuators and their meanings

Colour: RED
Meaning: Emergency situation
Description: Actuate in a dangerous or emergency situation. Emergency stop
Examples of application: Initiate emergency functions

Colour: YELLOW
Meaning: Abnormal condition
Description: Actuate if an abnormal condition occurs
Examples of application: Intervention to suppress an abnormal condition
Intervention to resume an interrupted automatic sequence

Colour: GREEN
Meaning: Normal condition
Description: Actuate to initiate normal conditions

Colour: BLUE
Meaning: Mandatory action
Description:
Actuate in a situation which requires a mandatory action
Examples of application: Resetting function

Colour: WHITE
Examples of application: START/ON (preferred) or STOP/OFF

Colour: GREY
Meaning: No special meaning defined
Description: General initiation of functions except emergency stop (see note below)
Examples of application: START/ON or STOP/OFF

Colour: BLACK
Examples of application: START/ON or STOP/OFF (preferred)

NOTE: If an additional coding feature (e.g. shape, position, surface finish) is used for marking pushbutton actuators, the same colours – WHITE, GREY or BLACK – may also be used to identify different functions (e.g. WHITE for START/ON and STOP/OFF actuators).

-----------------------------------------------------------

2. Symbolic marking

It is recommended to mark pushbuttons with the following symbols near the actuator or – preferably – directly on the actuator in addition to the functional identification described:

58c3caabde.jpg

START or ON
60417-IEC-5007

a8b3706746.jpg

STOP or OFF
60417-IEC-5008

8c29308d05.jpg

Pushbuttons with alternating START/STOP and ON/OFF function
60417-IEC-5010

86b07db810.jpg

Pushbuttons with START or ON function while being pressed and with STOP or OFF function when being released (i.e. inching)
60417-IEC-5011

-----------------------------------------------------------

3. Indicator lights and indicators

Applications

Indicator lights and indicators are used to provide the following information:

  • Indication: To draw the operator's attention to a specific circumstance or to indicate that a specific action should be performed. The usual colours used for this type of application are RED, YELLOW, GREEN or BLUE.
  • Confirmation: To confirm a command or condition, or to confirm the end of a change operation or transition time. Usually, BLUE and WHITE are used for this type of application; GREEN is permitted in some cases.

Colours

Indicator lights must have the colour coding according to table 3 unless otherwise agreed between the supplier and the purchaser. Other meanings deviating therefrom (refer to IEC 60073) may be assigned based on one of the following criteria:
  • Safety of persons and environment
  • Condition of the electrical equipment
Table 3: Colours of indicator lights and their meanings relating to the machine status

Colour: RED
Meaning: Emergency situation
Description: Dangerous condition
Operator action: Immediate action to respond to a dangerous condition (e.g. by pressing emergency stop)

Colour: YELLOW
Meaning: Abnormal condition
Description: Abnormal condition; anticipated critical condition
Operator action: Monitoring and/or intervention (e.g. by restoring the intended function)

Colour: GREEN
Meaning: Normal condition
Description: Normal condition
Operator action: Optional

Colour: BLUE
Meaning: Mandatory action
Description: Indication of a condition requiring operator intervention
Operator action: Mandatory action

Colour: WHITE
Meaning: Neutral
Description: Other conditions; may be used if there is uncertainty about the appropriateness of RED, YELLOW, GREEN or BLUE
Operator action: Monitor

-----------------------------------------------------------

Note: The above defines the general usage of colours as pushbuttons and indicator lights. This is for a clear standard on machinery.
It does not distinguish between a normal reset pushbutton and a safety reset pushbutton.

"Resetting pushbuttons must be BLUE, WHITE, GREY or BLACK...".

BLUE's meaning and usage is noted as a mandatory resetting function:

Colour: BLUE
Meaning: Mandatory action
Description: Actuate in a situation which requires a mandatory action
Examples of application: Resetting function

You are considering using WHITE which is noted as:

Colour: WHITE
Examples of application: START/ON (preferred) or STOP/OFF

GREY is either/or and BLACK is START/ON or STOP/OFF (preferred).

WHITE, GREY or BLACK are permitted as resets, but by interpretation of the above, BLUE is clearly intended to be the first choice for reset pushbuttons. There is no standard that states you must use BLUE for a safety reset, but just that BLUE is the first preference as a reset in general. It has, however, become the general norm for safety resets.

Indicator lights -

Unfortunately EN 60 204-1 doesn't quite cover illuminated pushbuttons as NFPA does, but I think the consensus here is to assume the colour of a light to be the same as the colour of the light on an illuminated pushbutton. The fact that the pushbutton and light meanings for BLUE are both defined as a mandatory action would support this.

Colour: BLUE
Meaning: Mandatory action
Description: Indication of a condition requiring operator intervention
Operator action: Mandatory action

So again, a BLUE light should indicate a mandatory action, which requires intervention from the operator e.g. an emergency stop reset.

Whereas a WHITE light is...

Colour: WHITE
Meaning: Neutral
Description: Other conditions; may be used if there is uncertainty about the appropriateness of RED, YELLOW, GREEN or BLUE
Operator action: Monitor

In other words, in general a WHITE can be used for any other conditions except for the conditions that RED, YELLOW, GREEN or BLUE normally indicate, and can only be used as a backup light colour if one the preferred colours is somehow inappropriate in some way.

So you should use the preferred BLUE light as a mandatory action indicator and also BLUE for non-illuminated pushbutton mandatory resets, regardless of whether they're safety or not. In cases where it's not a mandatory reset, say for a fault acknowledge, then you could use, for example, a BLACK pushbutton, or a WHITE illuminated pushbutton.

Regards,
George
 
Thank you goespark for a detailed reply,
Blue it is,
We have also been using non illuminated yellow as cycle pause for as long as I can remember looking at that reply I will have to change that as well my boss is going to love me :) I think just a normal black will do.

Thanks once again.
 
Thank you goespark for a detailed reply,
Blue it is,
We have also been using non illuminated yellow as cycle pause for as long as I can remember looking at that reply I will have to change that as well my boss is going to love me :) I think just a normal black will do.

Thanks once again.

Your boss will love you because the machinery will now comply with EN60204 and can be CE marked (as all should have been since 1995).

Two more things spring to mind before this thread dies a natural death:

1. In the information kindly reprodued by Geospark on indicators is states that Blue is for to draw attention to a mandatory action. I.E. The indicator should come on to indicate that the reset is required. Many people do this the other way round but, IMHO, they are incorrect.

2. Something else to considder. Have you verified that your safety circuits comply with EN13849? If your safety circuits were designed for EN954, they may not comply with EN13849.

Just a couple of thoughts,

Nick
 
A.B.Normal

danharding said:
...We have also been using non illuminated yellow as cycle pause for as long as I can remember looking at that reply I will have to change that as well my boss is going to love me :) I think just a normal black will do...

...Or...

shooter said:
keep it yellow, it is allowed, as you are interventing in a cycle

Which is correct?

I think a lot of these types of standards are open to interpretation.

EN 60204-1 said:
WHITE, GREY or BLACK are the preferred colours for pushbutton actuators with alternating START/ON and STOP/OFF function. RED, YELLOW or GREEN must not be used.

A CYCLE STOP/START, OFF/ON or PAUSE/RESUME pushbutton would seem to fit this description. So this would suggest that YELLOW is not permitted.

When can we use a YELLOW pushbutton?...

Colour: YELLOW
Meaning: Abnormal condition
Description: Actuate if an abnormal condition occurs
Examples of application: Intervention to suppress an abnormal condition/Intervention to resume an interrupted automatic sequence

So a YELLOW pushbutton may be used to intervene in an abnormal condition and for recovery from that condition.

shooter said:
...it is allowed, as you are interventing in a cycle

shooter,

I'm sure you're probably referring to situations where you are interventing for an abnormal condition, but by itself, the act of "interventing in a cycle" does not necessarily imply an abnormal condition exists. It may not always be installed for an abnormal condition, or likewise, it may not always be installed for a normal condition. So we cannot simply say that YELLOW is allowed for a CYCLE PAUSE/RESUME type pushbutton because you are "interventing in a cycle". The reason you are doing so will determine if YELLOW is allowed or not.

So we need to consider the reason the CYCLE PAUSE/RESUME pushbutton is being fitted to the machine...

Scenario 1: Normal Condition
Every so often, the operator needs to pause the cycle at a certain point to take a sample. This would be a normal condition for the operation of the machine and would not be classed as abnormal. So I would say use a BLACK pushbutton here - YELLOW is not permitted.

Scenario 2: Abnormal Condition
A product part, raw material, or a work piece is highly likely to foul up, or get caught at a certain point in the machine's cycle. This would be an abnormal condition. Good practice here would be to try and install a method of detecting this jam and pausing or stopping the cycle automatically. If this is not possible, then a CYCLE PAUSE/RESUME pushbutton may be fitted so as the operator can react to this condition. As the reason for the pushbutton is primarily for the intervention of an abnormal condition, and the recovery from that condition, then YELLOW would be permitted.

So we cannot categorically say that all CYCLE PAUSE/RESUME pushbuttons must be the preferred BLACK, and must not be YELLOW. But also, we cannot say that they all may be YELLOW. It's down to their intended use.

On the other hand, we don't want to be using two different colours for the same named pushbuttons depending on the scenario?

The rule-of-thumb I would follow is that an abnormal condition supersedes a normal condition. So to intervene and recover from an abnormal condition, use a YELLOW pushbutton, or illuminated pushbutton, and call it something more appropriate, such as HALT/RESUME or FAULT RECOVERY. For a normal condition CYCLE START/STOP, ON/OFF or PAUSE/RESUME pushbutton, use BLACK. If you want to continue using YELLOW for all your existing and future CYCLE pushbuttons, and still conform to the standards, then find a reason it's needed to intervene in an abnormal condition. :whistle:

George
 
Indicatively Indicated

Manglemender said:
...Blue is for to draw attention to a mandatory action. I.E. The indicator should come on to indicate that the reset is required. Many people do this the other way round but, IMHO, they are incorrect...

Manglemender,

You're quite correct here. Another thing that's open to interpretation is indicator states.

An indicator light that's normally OFF, coming ON, is far more attractive to the eye than one that's usually ON going OFF. This is why we use certain colours, and turn indicators lights ON for alarm/alert conditions. Flashing them further heightens their attractiveness. Normal permissive conditions, such as POWER ON, SYSTEM OK, SAFETY OK, CYCLE ON, END OF CYCLE COMPLETE, etc. are usually indicated by the the ON state because we associate them, and their colours, with "OK-TO-GO".

While not categorically stated in EN 60204-1, for indication designed to alert operators, an indicator's ON state should be indicative of that condition. So for an illuminated pushbutton, which is acting as a dual function indicator and RESET pushbutton, the light should be ON, or flashing to indicate a RESET is required, and not ON when the RESET is not required.

danharding said:
...I have generally done manual reset circuits with an illuminated push button that lights up when the E-Stop relay has been reset...I have always used green in the past...


In Dan's case, he's been using a GREEN illuminated pushbutton as a dual function RESET. One function is to RESET, the other function being to indicate it's status. Firstly, for the RESET, GREEN is not permitted here, it should be BLUE. Secondly, and as you've reiterated, a BLUE indicator should be indicative of a mandatory condition that requires action by the operator. This means it should come ON to attract the operator's attention. Thirdly, the function of indicating the status of the RESET when it is RESET, should be done separately. Again, using a permissive indicator and colour, such as GREEN, which is described as for indicating a normal condition, and labeling it, for example, "SAFETY OK".

That last part is usually the problem. People don't want to have to add another indicator light, so they make the RESET pushbutton illuminated and pick a colour they want normally ON, or pick the right colour, BLUE, and make it normally ON.

Another method I've seen is to have the BLUE illuminated RESET pushbutton normally ON, and when a RESET is required, it flashes. Once RESET, it goes back to normally ON. This is usually labeled "SAFETY OK" or "SAFETY HEALTHY". While this isn't strictly correct either, it could be argued that flashing the light makes it more attractive than when it's solid ON and would alert an operator.

Here's a little more from EN 60204-1...
(Comments in italics are mine)


10.3.1 General

Indicator lights and displays serve to give the following types of information:

– indication: to attract the operator's attention or to indicate that a certain task should be performed. The colours RED, YELLOW, BLUE, and GREEN are normally used in this mode; for flashing indicator lights and displays, see 10.3.3. (* See below).

While GREEN is permitted here as an indicator to attract an operator's attention, it is still not permitted for a mandatory RESET.

– confirmation: to confirm a command, or a condition, or to confirm the termination of a change or transition period. The colours BLUE and WHITE are normally used in this mode and GREEN may be used in some cases.

But not for a mandatory RESET.

Indicator lights and displays shall be selected and installed in such a manner as to be visible from the normal position of the operator (see also IEC 61310-1).

Indicator light circuits used for warning lights shall be fitted with facilities to check the operability of these lights.

I've seen CE marked machines without a lamp test facility.


10.3.2 Colours

Indicating towers on machines should have the applicable colours in the following order from the top down; RED, YELLOW, BLUE, GREEN and WHITE.


* 10.3.3 Flashing lights and displays

For further distinction or information and especially to give additional emphasis, flashing lights and displays can be provided for the following purposes:

– to attract attention;
– to request immediate action;
– to indicate a discrepancy between the command and actual state;
– to indicate a change in process (flashing during transition).

It is recommended that higher frequency flashing lights or display be used for higher priority information (see IEC 60073 for recommended flashing rates and pulse/pause ratios).

Where flashing lights or displays are used to provide higher priority information, audible warning devices should also be provided.


10.4 Illuminated push-buttons

Illuminated push-button actuators shall be colour-coded in accordance with Tables 2 and 4.

Where there is difficulty in assigning an appropriate colour, WHITE shall be used. The colour RED for the emergency stop actuator shall not depend on the illumination of its light.

Everyone has their own preferences, and in the real world a pushbutton is a pushbutton, and an indicator light is an indicator light, but for CE conformity, you should follow these standards.

George
 
IEC EN 62062 and ISO EN 13849-1

Manglemender said:
...Have you verified that your safety circuits comply with EN13849? If your safety circuits were designed for EN954, they may not comply with EN13849...

Further clarification...

EN 60204-1 - Safety of Machinery - Electrical Equipment of Machines

Part 1: General requirements

9.4 Control functions in the event of failure

9.4.1 General requirements

Where failures or disturbances in the electrical equipment can cause a hazardous situation or damage to the machine or to the work in progress, appropriate measures shall be taken to minimize the probability of the occurrence of such failures or disturbances. The required measures and the extent to which they are implemented, either individually or in combination, depend on the level of risk associated with the respective application (see 4.1).

The electrical control circuits shall have an appropriate level of safety performance that has been determined from the risk assessment at the machine. The requirements of IEC 62061 and/or ISO 13849-1:2008, ISO 13849-2:2003 shall apply.


EN 954-1 - Catagory/Fault Tolerance/Diagnostics was withdrawn in 2011. ISO EN 13849-1, which primarily deals with Performance Level (PL) for Safety-Related Parts of Control Systems (SRPCS), replaced EN 954-1 and can be used for any energy source.

If a specifically designed PLC is controlling the safety system, then you would refer to IEC EN 62061, which primarily deals with the Safety Integrity Level (SIL) of Safety-Related Control Systems (SRCS).

The future...

Plans are already under way since 2011 to merge...

ISO EN 13849-1 Safety of Machinery - Safety-Related Parts of Control Systems (SRPCS) - Part 1: General Principles for Design

...and...

IEC EN 62061 Safety of Machinery - Functional Safety of Safety-Related Electrical, Electronic and Programmable Electronic Control Systems (SRCS).

This way, safety engineers and safety product manufacturers can refer to one set of standards for safety calculations for PL, PFHd, MTTFd, SFF, SIL CL, etc.

It's rumoured that it's going to be called ISO/IEC 17305.

Regards,
George

ISO_13849+IEC_62061.jpg
 
What do you think Geospark. For safety circuit reset button, we have one system with off = ok; flashing = tripped, not ok to reset; light up no flashing = tripped, ok to reset.
 
It's always BLUE

After an Estop it is necessary for the operator to do a reset (mandatory action)

Geospark wrote:
From EN 60204-1
Colour: BLUE
Meaning: Mandatory action
Description: Actuate in a situation which requires a mandatory action
Examples of application: Resetting function
 

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