Mitsubishi UPS 9900b Modbus Registers


Thread Starter


Hello everyone,

This is probably a dumb question for most people here but I've been three days struggling with this list and I can't find a way to solve it.

I have a register list for a Mitsubishi UPS 9900b. On tables 1-5 I'm ok with all registers but in Table 6, as below pictures link show, I don't understand the relation between the register and the value, I got registers:

3x2016 and so on..

and values:
up to X=108, each one with a different alarm description

Does anyone knows how to interpret that relation between register and value?. What type of register is that?

I'm using Niagara AX to expose the values in the frontend but I can't find a proper way to expose the modbus point.

I hope you guys can see the pics.

Thanks in advance and have a great evening.

Bob Peterson

Just an educated guess but I think the ex is supposed to indicate that it can be either a five or six digit address. I would just take the X Out and use that as the address. It appears to me that the x equals stuff is a list of the last 10 alarms with the value of x indicating the alarm that occurred.
Thank you for the reply Bob

Yes, that's what I thought. the address is fine. it is 32000 as in Niagara AX you can only use 5 digit addresses. the point in the database is stable. but what I'm trying to understand, if you look at the third picture, is how do I know i.e. when X=21 (Battery voltage abnormal) is active?

How is that value related to the register itself? Is it a register bit point?

Thanks again