Yes, that's definitely an MC30 system. The main module (the PLC itself) is mounted on the panel with two I/O extension modules (the IO30's) piggybacked on it. Boy, it was over 20 years ago when I used to work with those babies.
The programming language is PC20 and was used for the PC20, MC20 and MC30 family of PLCs. The instruction set consists of only 31 low level mnemonic instructions. The addresses range consists of 4 pages of 512 nibbles (4 bits). Only the first page is bit-addressable. It doesn't even know a timer instruction: you have to count clockpulses in several BCD registers to construct a timer, you do the same but without the clockpulses to construct a counter. Those days we had to know how a timer did work, if not we couldn't even program one. But it did use BCD instructions to count and do math (add, subtract, divide and multiply only). Programming calculations had a lot in common with doing math on paper, long divisions and so on.
I hope you're able to find the PDS3.5 software, if not you'll have to find a handterminal and save the program on audio tape. Or type it in entirely whenever you want to change something.
Kind regards,