7.1
Routine Maintenance of Safety Control
Unit
There are two ways of inspecting safety control unit. The status of whether the each module
status display LEDs are turned on or off, (can be checked visually), or the system status can
be checked in the SCS state management window at SENG.
n
Antistatic Precautions
When doing maintenance work, take the following full precautions to avoid electrostatic prob-
lems.
•
When storing or carrying parts for maintenance, put them in an antistatic bag. (When
shipped, they are placed in an antistatic bag labeled with cautions against electrostatic
problems.)
•
Wear a wrist strap with a 1M ohm grounding resistor then ground the wrist strap.
•
When working on the bench, place the parts on a conductive sheet grounded via a 1 M
ohm resistor and wear wrist strap. Keep static-chargeable plastic materials away from the
parts.
•
Never touch the parts with bare hands, without using a wrist strap and a conductive
sheet.
Wrist strap
Conductive sheet
Grounding resistance
of 1 M ohm
Wrist strap
Connect the wrist strap to the grounding terminal or
unpainted part of the frame (grounded).
When working with a product with battery on
a conductive sheet, set the battery ON/OFF
switch to the OFF position or remove the battery.
1M ohm
1M ohm
Figure 7.1-1 Using a Wrist Strap
The wrist strap and conductive sheet are available from Yokogawa’s sales agents.
<7.1 Routine Maintenance of Safety Control Unit >
7-2
IM 32Q06C10-31E
4th Edition : Jan.30,2015-00
