Field Service Bulletin 5: Electrostatic Discharge and SBE 41 & 41CP CTD Sensors
Damage can occur if an electrostatic discharge is made to the titanium pressure port on Sea-Bird CTD-equipped ARGO floats manufactured prior to early 2004. The pressure sensor, and possibly the interface circuitry, can be damaged by ESD.
In early 2004, Sea-Bird installed transient surge protectors to help protect SBE 41 / 41CP CTDs from electrostatic discharge damage . However, large numbers of unprotected CTDs, manufactured before that date, remain at risk. Even after installation of surge protectors, float manufacturers and end users should continue to observe good ESD-prevention practices, especially when handling unmounted CTD/endcap assemblies.
- The transient surge protectors are installed on SBE 41 with PCB assembly 40935Q and serial number 1415 and later; and SBE 41CP with PCB assembly 41015N and serial number 0796 and later.
Avoid wearing rubber-soled shoes. Avoid scuffing (sliding) your feet on carpeted surfaces. Discharge yourself by touching a grounded object.
Some examples of grounded objects include:
computer chassis, especially the bare metal back panel
small screw that secures a wall switch or socket
ship's hull or steel deck
Specifc Precautions, Assembled Floats
|1. Ground yourself.|
|2. Then, grasp the float housing before touching the titanium pressure port.|
|3. Finally, first grasp the float endcap and then touch the pressure port before and while making electrical or mechanical connections to the pressure port.|
Specific Precautions, CTD Disassembled from Float
The CTD electronics and sensors should be treated like any unassembled semiconductor device:
- Avoid carpets in cool, dry areas. Leave PC cards in their anti-static packaging until ready to be installed.
- Dissipate static electricity before handling any system components (PC cards, sensors) by touching a grounded metal object (see above).
- If possible, use antistatic devices, such as wrist straps and floor mats.
- Always hold a PC card by its edges. Avoid touching the contacts and components on the card.