Mitsubishi problem

I am using a Mitsubishi A2AS-S1 CPU. I want to set some markers in the internal buffer memory of an ethernet module. To do so I am using the TOP_M function. I use the following variables:
s = ConnectionNo (Type: WORD, value: 16#8003)
n1 = HeadAddress (Type: WORD, value: 8)
n2 = 33
n3 = 1

When I compile my project I get an error saying: "Illegal device used or symbol not valid : TOP W235 H21 W237 H1"

However, when I change input n1 of the TOP_M function from "HeadAddress" to "8" it compiles without a problem.

Can anybody tell me the cause of this strange error, and if so, what can I do to overcome it.

Thanks in advance
Caspar

cmulder,

          n1  n2  (S)  n3 

----[TOP W235 H21 W237 H1]----

The n1 is where your ethernet module is located or what slot on the rack is it plugged into. This has to be represented as a numerical value like H8 or K8. If your ethernet module is plugged into I/O slot 2 the n1 on your buffer memory write function would be H2 or K2 not a link register as you have it. Your (S) is where the data is located thats going to be written. The buffer memory itself is nothing more then a place for other I/O units or other modules to get together to exchange data.
Tim

Second try,.....

cmulder,

          n1  n2  (S)  n3 

----[TOP W235 H21 W237 H1]----

The n1 is where your ethernet module is located or what slot on the rack is it plugged into. This has to be represented as a numerical value like H8 or K8. If your ethernet module is plugged into I/O slot 2 the n1 on your buffer memory write function would be H2 or K2 not a link register as you have it. Your (S) is where the data is located thats going to be written. The buffer memory itself is nothing more then a place for other I/O units or other modules to get together to exchange data.
Tim

Tim,

Thanks for your reply. I think you are right. I have to use a value like K8. Using a variable just doesn't work. I have noticed that with a QnA-series however it does work.

I'm a bit disappointed now because I wanted to write a library function for Ethernet-communication. However for this I would have needed to enter the headaddress for writing to the buffermemory. I guess I have to think of another way...

Caspar

You should create a function block with input parameter Address as integer. Inside the function block you can use TO instruction with n1 parameterised as Address. It will work. But in a program it does not work because the CPU does not allow a variable as the first parameter for the TO instruction. In a function block it is different.