In some Seriplex applications there is a desire to service more than the 255 discrete input bits permitted on a single Seriplex network. This can be made possible by multiplexing the input devices. Ordinarily, however, discrete devices cannot be multiplexed directly onto the Seriplex network. To provide this capability, NR&D has developed a Seriplex Input Multiplexer (SIM).
The SIM is a device which allows strings of Seriplex input devices to be multiplexed to the Seriplex Master device. This theoretically extends the input capability of a Seriplex network from 255 discrete bits to 3,824 discrete bits. The SIM will address a "branch" of Seriplex inputs connected to the main Seriplex "trunk". All of the inputs on the branch will be seen by the Seriplex master when its multiplexed channel address matches the address set on the SIM. At other times the branch devices will continue to output their data but the SIM will block this so that the master cannot see it.
The SIM is a small, DIN rail mountable module with two Seriplex connectors for attachment to the main Seriplex trunk and to the multiplexed branch. Seriplex multiplexed channel address and mode are set with a DIP switch on the unit.
Every device on a multiplexed branch should be a non-multiplexed device or a multiplexed device with only one channel. The channel must have the same address as the associated SIM. Multiple SIMs can be connected to a single Seriplex network. These can have different multiplex addresses, although SIMs can also be configured to use the same multiplex address. All of the devices on branches with SIMs that have the same multiplex address will respond at the same time. A SIM can be connected to the main Seriplex line but should never be connected to a branch that is already multiplexed by another SIM. If they have the same address then only one SIM is needed; if they have different addresses then the devices from the downstream SIM will never be seen by the master since the first SIM will be blocking inputs for every address except its own.
Due to the multiplexing scheme, input reports from multiplexed channels occur less often than do input reports from non-multiplexed networks. This should be kept in mind when designing the Seriplex layout. Time critical inputs should be placed on the non-multiplexed portion of the Seriplex network. In addition, the master should address the minimum number of Seriplex channels possible.
The input devices on multiplexed channels are configured in the same manner as normal input devices, with Seriplex addresses. The addresses on the multiplexed section must be between 16 and 255. Duplicate addresses can be used on separate multiplexed branches and they will not interfere with each other as long as the SIMs have different channel addresses. Inputs with duplicate addresses on separate multiplexed branches with identical SIM addresses will be ORed together, that is, if either device is on (or both are on) the master will see that input as on.
Non-multiplexed inputs report on every Seriplex scan, regardless of the multiplexed channel being addressed. Because of this, if an input on a multiplexed branch has the same address as an input on a non-multiplexed branch then the non-multiplexed input will report at the same time as the multiplexed input. This might be desirable, depending upon your application, but it can be a source of confusion. The SIM will multiplex inputs but does not multiplex outputs. Both Seriplex mode 1 (peer to peer) and mode 2 (host CPU) are supported.
The SIM is also useful as a diagnostic tool when constructing or configuring Seriplex systems; using a SIM, any branch of a Seriplex network can be isolated.
The Niobrara SIM is furnished with instructions and examples and carries a one year warranty. See Niobrara's Standard Terms and Conditions of Sale for additional warranty information.
Dimensions: 3.8" x 1.5" x 1.7" deep (including DIN rail mount). Approximately 2.5 oz. (71g.)
Power Requirements: From Seriplex bus; 12 or 24v, 30mA max.
Seriplex Connector: Phoenix Combicon 5-pin connector.
Multiplexed Device Connector: Phoenix Combicon 5-pin connector.
Controls: DIP switch sets address, Seriplex mode.
The SIM is available as:
SIM with Seriplex connectors for Seriplex network and multiplexed input devices