Banner ES-UA-5A Instruction page 11

ES-UA-5A and ES-VA-5A E-Stop Safety Modules
Overvoltage Category II and III Installations (EN 50178 and IEC 60664-1)
The Safety Module is rated for Overvoltage Category III when voltages of 1V to 150V ac/dc are applied to the output
relay contacts. It is rated for Overvoltage Category II when voltages of 151V to 250V ac/dc are applied to the output
relay contacts and no additional precautions are taken to attenuate possible overvoltage situations in the supply
voltage. The Module can be used in an Overvoltage Category III environment (with voltages of 151V to 250V ac/dc)
if care is taken either to reduce the level of electrical disturbances seen by the Module to Overvoltage Category II
levels by installing surge suppressor devices (e.g., arc suppressors), or to install extra external insulation in order
to isolate both the Safety Module and the user from the higher voltage levels of a Category III environment.
Overvoltage Category III Installations
When output contact voltage 151V to 250V ac/dc is applied to the output contact(s): the Safety Module may
be used under the conditions of a higher overvoltage category where appropriate overvoltage reduction is provided.
Appropriate methods include:
An overvoltage protective device
A transformer with isolated windings
A distribution system with a multiplicity of branch circuits (capable of diverting energy of surges)
A capacitance capable of absorbing energy of surges
A resistance or similar damping device capable of dissipating the energy of surges
When switching inductive ac loads, it is good practice to install appropriately-sized arc suppressors to protect the
Safety Module outputs. However, if arc suppressors are used, they must be installed across the load being switched
(e. g., across the coils of external safety relays), and never across the Safety Module's output contacts (see
WARNING, "Wiring of Arc Suppressors").
Auxiliary Monitor Contact/Solid-State Monitor Outputs Connection
The action of the auxiliary monitor contact (terminals 51-52) inversely "follows" the action of the safety outputs. There
are also two solid-state monitor outputs, each capable of switching up to 100 mA at 12-24V dc. One output at terminal
Y32 follows the action of the output circuits (K1 and K2); the other output at terminal Y35 opens (low signal) when
there is a loss of power or a fault is detected. A typical use for these outputs is to communicate the status of the
Safety Module to a programmable logic controller (PLC). See hookups for more information. These outputs are to
be used only for control functions that are NOT safety-related.
WARNING . . . Wiring of Arc Suppressors
If arc suppressors are used, they MUST be installed as shown across the actuator coil of the Master Stop
Control Elements (MSC1 to MSC4). NEVER install suppressors directly across the output contacts of the
Safety Module. It is possible for suppressors to fail as a short circuit. If installed directly across the output contacts
of the Safety Module, a short-circuited suppressor will create an unsafe condition which could result in se-
rious injury or death.
WARNING . . . Interfacing MSCs
NEVER wire an intermediate device(s) (e.g., PLC, PES, PC) between the Safety Module outputs and the
Master Stop Control Element it switches in such a manner that in the event of a failure there is a loss of
the safety stop command, OR in such a manner that the safety function can be suspended, overridden, or
defeated, unless accomplished with the same or greater degree of safety.
Whenever forced-guided, mechanically linked relays are added as intermediate switching devices, a normally
closed forced-guided monitor contact from each relay must be added to the series feedback loop between Safety
Module terminals S31 and S32.
P/N 122365 rev. C Banner Engineering Corp. - Minneapolis, MN USA - www.bannerengineering.com
Tel: 763.544.3164
11