GEM 80 500 Batteries.
GEM 80 500 Controllers have their lithium backup battery soldered onto the main CPU’s printed circuit board.
The Saft LS14500 3.6v lithium battery is fitted into the GEM 80 500 controller. The battery life expectancy within the GEM 80 500 is an impressive 10 years, but unfortunately as the battery is soldered onto the main CPU circuit board using bespoke solder tabs, it has always been required to take the GEM 80 500 out of service and returned to the factory for battery replacement. Unfortunately the factory producing these GEM 80 500’s has now closed. If you wish to find out more about replacing these batteries, please email us at info@autoac.uk where will be happy to assist.
The GEM 80 500 PLC does however include an (EEPROM) flash memory area so that the GEM 80 ladder program can be transferred to this and run directly from here rather than the battery backed RAM. Instructions on how to achieve this feature of the GEM 80 500, negating the requirement for fitting a replacement battery can be found in a video on our YouTube channel Automation Academy.
GEM 80 131 and 400 Batteries.
The battery life expectancy within the GEM 80 400 and GEM 80 131 controllers is approximately 2 years and simply requires that the coin cell battery is replaced from the front of the GEM 80 400 CPU.
However before you replace the battery check the type of battery that is fitted. There can be 2 different types of battery fitted to these GEM 80 CPU’s and inserting the incorrect replacement battery will blow the CPU, an expensive mistake to make!
The reason that there are two different type of battery relates to an error in sourcing the battery holder and battery combination at the factory when the CPU’s were originally built. Some holders had the CR2477N battery fitted and other CR2477 or CR2477P, although these batteries are the same size the polarity of the cell is reversed. This error was not noticed at the factory during production until some time later when all new holders were then made as CR2477N.
The CR2477N shown above is the most common of these two types of battery for the GEM 80 131 or 400 CPU’s. We have these in stock and we can provide them for you if required, please email us at info@autoac.uk if you wish to purchase these batteries.
Pre GEM 80 131 RAM Module Batteries.
The lithium batteries on earlier GEM 80 controllers were fitted onto the seperate RAM modules. These were a custom made Saft lithium cell specifically made for the GEM 80 RAM module. They have flying leads with connection tabs to connect the battery to the RAM module. We have a replacement battery that we have available to replace these old discontinued batteries, please contact us if you require one.
Depending on the age of the GEM 80 RAM module then there are 3 versions available. The lithium battery is the same on all RAM modules but the method to access the battery is different.
The earliest of these RAM modules have the battery fitted onto the module, it can only be replaced by powering the system down and removing the module to get access to the battery. Not particularly useful if the GEM 80 is in production. Because of this the RAM module has a 3.5mm jack socket fitted to the front of the module to allow a temporary battery to be connected externally until a convenient time was available for the on board backup battery to be replaced.
The second type of RAM module again had the Lithium battery mounted internally on the module itself however it featured a backup capacitor to back the RAM up during the battery change over process, again with the module removed. This RAM module capacitor was supposed to have about a 20 minute backup provision for replacing the old on board battery, however in practice the time you have to replace the old battery with the new is much less, maybe as low as 20 seconds. Always be prepared to reload the program if dealing with this type of RAM module when replacing the battery.
The third version of this module gave access to the battery through an cut out in the front of the RAM module, this means that the battery can be removed while the GEM 80 is still powered up, thus removing the requirement for any other type of backup during changeover as long as the GEM 80 power supply is maintained. These RAM modules can also feature a cut out for an optional EPROM submodule that could be used to copy the RAM program to. On these GEM 80 controllers the program would be loaded into RAM from the optional EPROM on power up, the program would then run in RAM. To clear and reuse the EPROM did however require the use of a UV EPROM eraser, as these units were not EEPROM (flash) memory devices.
If you require help or advice on any aspect of GEM 80 batteries please contact us on info@autoac.uk and we will be happy to help out.
If you would like to view our comprehensive range of GEM 80 PLC training courses that we can tailor to your exact requirements, then please click on the following link to our course information: GEM 80 Training Courses.