Issue
MRs going to Sleep
Environment
I/NET Seven site with MR's
Cause
When certain DDC Modules are being used in an MR it uses both the NOV RAM and RAM Memory
Resolution
When certain DDC Modules are being used in an MR it uses both the NOV RAM and RAM Memory.
When writing DDC care should be taken so as to not exceed the amount of memory that is within the device itself. It has 130 Bytes of RAM and 1024 Bytes of NOVRAM.
The MR supports six DDC module types and an interconnected control configuration up to 16, depending upon the types. It may appear that the memory is not maxed out, when it is all added up but it causes the MR to “go to sleep”. The user will have to go to the MCU Configuration and turn that MR Internal and then External again, to “wake it up”.
Depending upon the application, if there are more than 4 PID modules, the first 4 work, but the others do not.
This can also occur if there is a huge calculation on one of the points, the same symptom and result will apply. Please be selective as to which module and function you’re using for your application.
Note: MR-resident DDC modules only reside in the MR (not in the MCI, MRI or I/Site LAN. Therefore, these modules are not available for use in any MR tagged as Internal in the MCU configuration editor.)
The following table shows the amount of memory that each item uses:
| Points | ||
| Point | NOVRAM Bytes | RAM Bytes |
| DI Point | 4 | 1 |
| DA Point | 4 | 1 |
| DM Point | 4 | 1 |
| DO Point (Internal) | 4 | 1 |
| DO Point (External) | 4 | 3 |
| DC Point (Internal) | 4 | 1 |
| DC Point (External) | 4 | 3 |
| AI Point (Internal) | 16 | 3 |
| AI Point (External) | 16 | 5 |
| AO Point (Internal) | 16 | 3 |
| AO Point (External) | 16 | 5 |
| PI Point | 4 | 2 |
| Modules | ||
| Module | NOVRAM Bytes | RAM Bytes |
| PID Module (Without Filter) | 40 | 14 |
| PID Module (With Filtering) | 40 | 19 |
| Floating Module (Without Filter) | 40 | 12 |
| Floating Module (With Filter) | 40 | 17 |
| Two Position Module (W F) | 28 | 2 |
| Two Position Module (W/O F) | 28 | 7 |
| Relay Module (Standard) | 20 | 2 |
| Relay Module (DBB, DBM, INT) | 20 | 4 |
| Reset Module | 48 | 2 |
| Calculations | ||
| Calculation | NOVRAM Bytes | RAM Bytes |
| Calculation Modules Overhead Module (fixed) | 6 | 2 |
| Each Operator (+, -, *, /, etc) | 1 | N/A |
| Each Point Address (P0, P1, etc) | 2 | N/A |
| Each Constant (C0, C1, etc) | 4 | N/A |
| Each Line (L0, L1, etc) | 1 | N/A |
| Calculation Module Total | * | 2 |
| Lines | ||
| Lines | NOVRAM Bytes | RAM Bytes |
| MR-DDC Lines | N/A | 4 |
Note: Verify that you are using the most current EPROM for the revision of software that you are running.
