OTB Series Optical Touch Button Product Manual

13-Nov-24

page 3 of 10

© Banner Engineering Corp. All rights reserved.

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CAUTION:

Install hand controls to prevent accidental actuation

It is not possible to completely protect the two-hand control system from defeat.

OSHA regulations require the user to arrange and protect hand controls to minimize possibility of defeat or

accidental actuation. 

WARNING: Never use an OPTO-TOUCH Optical Touch Button as an actuator in an emergency stop (E-Stop) circuit. E-

Stop actuators must be purely mechanical devices that require no power to operate. OPTO-TOUCH Optical Touch

Buttons require power to operate and must not be used as E-Stop actuators under any circumstances.

Two-Hand Control

Two-Hand Control is an operator actuating control that initiates a machine cycle through the synchronous use of both buttons and concurrent

actuation during the hazardous portion of the machine cycle. Synchronous use is defined as the actuation of both buttons within 500 ms of

each other. If one or both buttons are released, an immediate stop command is issued to the machine control and the hazard ceases at any

point in the machine cycle.

Alternatively, Two-Hand Trip is similar, but typically initiates a full machine cycle and does not cause a stop or cessation of the hazard if either

or both the buttons are released. Two-Hand Trip is typically used on single-cycle or full-revolution machines.

In addition to the general installation requirements listed above, Two-Hand Control/Trip can be used for simple machine cycle actuation and

must comply with NFPA 79 and/or ISO 60204-1. If the Two-Hand Control/Trip is also used for safeguarding, additional requirements must be

complied with and are found in ANSI B11.19, ISO 13851 and other relevant regulations. In either case, the machine (safety) control must also

provide the appropriate level of safety performance (risk reduction) as determined by a risk assessment and the functions of anti-tiedown and

anti-repeat.

The level of the safety performance of a Two-Hand Control/Trip system depends on the actuating controls (buttons) and the circuity/logic

monitoring those actuating controls (THC modules, Safety Controllers, etc.). Typically, systems incorporating OPTO-TOUCH Optical Touch

Buttons are limited to Type IIIA or IIIB per ISO 13851. If a Type IIIC system is required, STB Self-Checking Optical Touch Buttons (datasheet

p/n 64136) and an appropriate Two-Hand Control logic module or Safety Controller (for example, AT-FM-10K, SC26/XS26, SC10) can

comply with the additional requirements.

Anti-tiedown requires the release of both buttons before a subsequent cycle can be re-initiated. This applies after a cycle has been

completed or if a stop has otherwise occurred. The anti-tiedown function must be designed to ignore false input signals. False signals include

(but are not limited to) voltage transients, contact bounce, and EMI or RFI noise. Two-Hand Control logic modules and Safety Controllers

with anti-tiedown are available, which include circuitry to minimize the possibility of false actuation.

Anti-repeat function causes a stop at the end of the machine cycle and requires release of all actuating controls (for example,, buttons)

before another cycle or stroke can be initiated. The anti-repeat function must be incorporated into the machine and/or the machine (safety)

control.

Other installation considerations include that the actuating controls (for example, buttons) must be arranged far enough apart so that the

operator cannot operate both actuating controls using one arm or hand. And, both actuating controls must be located far enough away from

the nearest hazard that the operator cannot reach the hazard with a hand or other body part before the hazardous motion or situation

ceases. Installation considerations, including the separation distance (safety distance) and calculations to determine this distance are found

in ANSI B11.19 or ISO 13851.

WARNING:

Mount hand controls at a safe distance from moving machine parts

Failure to establish and maintain the safety distance (minimum distance) could result in serious injury or death.

Mount hand controls as determined by the applicable standard. The operator or other non-qualified persons

must not be able to relocate the hand controls.

WARNING:

Use adequate point-of-operation guarding

Failure to properly guard hazardous machinery can result in a dangerous condition that could lead to serious

injury or death.

When properly installed, a two-hand control safety device provides protection only for the hands of the

machine operator. It might be necessary to install additional safeguarding, such as safety light curtains,

additional two-hand controls, and/or hard guards, to protect all individuals from hazardous machinery.