Wow, you do have a very obsolete PLC! From what I can find out this model was first introduced in 1982 and replaced in 1986 with Sharp support for the ZV series terminating in 1993. I had hoped to help you with spare modules removed from equipment we have replaced but your ZV series predates...
Hello Speclab, Working for a Japanese company that uses a large number of Sharp controllers, perhaps I can help you find a source so that you don't have to throw away a perfectly good PLC! Please answer the following questions:
What model Sharp are you using?
Which I/O modules are you using?