The RMC151E CPU module is identical to the RMC150E, plus adds the ability to do dual-loop control. Dual-loop control means controlling with two feedback transducers such as position and pressure, or position and force, with the same actuator.
When ordering an entire RMC151E controller, which includes the backplane, CPU and any modules, the difference between the RMC150E and RMC151E is fairly straight-forward. Just order the one you need! Notice that on the RMC151E CPU, the front of the module says RMC150E, but the label on the side of the entire controller will say RMC151E and RMCTools will recognize it as RMC151E.
Things become more confusing if you need to order just a CPU module, or if you replace analog modules. This is because the dual-loop feature is actually activated by a special feature in the analog input modules (H, A, G, and UI/O). In order for a CPU to be an RMC151E, all the analog modules in the backplane need to have the dual-loop feature set. Otherwise, the CPU will just be an RMC150E. It doesn’t matter what the CPU was originally. The RMC150E and RMC151E CPUs are actually entirely identical - the difference is only in the analog modules!
So, if you need to order just an individual RMC151E CPU module, you will actually be ordering the RMC150E. You need to make sure your analog modules all have the dual-loop feature. If they do, the CPU will be an RMC151E. There is no way to directly check if an existing analog module has the dual-loop feature, but if an analog module came from a controller that was an RMC151E, then you know that analog module has the dual-loop feature. You can also call Delta and we can look up the serial number to see if it is supposed to have the dual-loop feature.
Also, if you are replacing or adding analog modules on an RMC151E, you must make sure the analog module has the dual-loop feature.
When ordering an individual analog module (not as part of an entire controller), the part number defines whether it has the dual-loop feature:
- RMC101-H is an H module with the dual-loop feature
- RMC100-H is an H module without the dual-loop feature
The dual-loop feature on the analog modules can only be set at Delta Computer Systems. If you have an analog module to which you want to add the dual-loop feature, you will need to send it to Delta, and there will be a charge.
Now, you may be wondering why this is done in such a confusing way. The answer is that it comes from the previous generation of CPU, the RMC100/101. Due to various limitations of that technology, this was deemed the best method. The RMC150/151 uses the same backplane and modules as the RMC100/101, so the dual-loop method could not easily be changed without causing a lot of confusion. Delta’s goal is to make future products less confusing.