Recently, we had a customer who wanted to upgrade from a GE IC693CPU364 to a GE IC693CPU374 because they believed the CPU374 had more password characters. Here is our Senior PLC Engineer’s answer:
No, it is not true. The maximum length of the password is 6 ASCII characters whether it is an IC693CPU364 or an IC693CPU374. The only length restrictions that I have found is if the user is using Logicmaster 90 or a Hand Held Programmer, both of which limits the length to 4 ASCII characters. I have done some testing and I have found that the password can contain any ASCII character except a space and a tab and it is case sensitive. I believe this will fulfill the complexity requirement for your applications.
As far as the CPU364 is concerned, it would be better if they were replaced by CPU374s because the CPU364 has been discontinued for a few years. The programs in the CPU364 are directly transportable to a CPU374. All that would be needed would be a configuration change in the folder. The primary ‘gotcha’ in converting to CPU374s is that the CPU374 will use up the standard battery after 5-6 weeks of power-down time (versus 6 months for the CPU364). I would recommend that if CPU374s are installed, an auxiliary battery (IC693ACC302) should be installed with each one. This will provide 15 months max. power-down backup capability. An alternative to the CPU374 would be to use the CPU372, which has half the memory capacity at a lower price. However, this would require converting their programming s/w from VersaPro to Proficy Machine Edition (VersaPro does not support the CPU372) and making sure that a high capacity power supply is used with the CPU (Proficy requires that a high-capacity p/s be used with the CPU372 and CPU374). (To learn how to install an IC693ACC302 for use with an IC693CPU374, go to our video library).
In addition, Qualitrol International will buy any used IC693CPU364 modules that you take out of a system. Simply call us at 1-800-784-9385 and we will give you all of the details.