1771-DRS1

The 1771-DRS1 RAM chip is a 1 MB static RAM chip. Note that this optional RAM SIMM chip is not the same as RAM chips that are used in personal computers. The 1771-DRS1 RAM SIMM chip is a special static RAM chip which is compatible with control coprocessors including the 1771-DMC, 1771-DMC1, 1771-DMC4, and the 1771-DXPS control coprocessors. Other optional memory modules that are available include the 256 MB 1771-DRS module and the 4 MB 1771-DRS4 module. It is important to note that if the optional memory module such as the 1771-DRS1 RAM chip is located in the second SIMM socket of the coprocessor and if that second SIMM socket is configured for battery backup, then a power cycle could cause the corruption of the memory module located in that second socket. This problem does not affect 1771-DMC, 1771-DMC1, and the 1771-DMC4 coprocessors which come in standard factory configurations. In fact, this problem only affects memory modules that are located in the second SIMM slot for older coprocessors.

For the 1771-DMC coprocessors, the older part models that are affected by power cycles corrupting the memory modules like the 1771-DRS1 module in the second sockets include the 96102271, 96102274, 96102277, 96845871, 96845872, and the 96845873 coprocessors. For the 1771-DMC1 coprocessors, the affected part numbers include the 96102272, 96102275, 96102278, 96845971, 96845972, and the 96845973 coprocessors. For 1771-DMC4 coprocessors, the affected part numbers include the 96102273, 96102276, 96102279, 9686071, 9686072, and the 96846073 coprocessors. If the users have one of these mentioned part numbers and they want to install and configure the second SIMM socket for battery backup, then the module should be returned to Allen-Bradley for upgrades first, or it may need to be replaced with a newer model. The control coprocessors and the memory modules like the 1771-DRS1 module have an operating temperature range of 0 to 60 degrees Celsius and storage temperature range of -40 to 85 degrees Celsius.